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OFFICE OF APPLIED STUDIES



Drug Abuse Warning Network, 2006:
National Estimates of Drug-Related Emergency Department Visits



U.S. DEPARTMENT OF HEALTH AND HUMAN SERVICES
Substance Abuse and Mental Health Services Administration
http://DAWNinfo.samhsa.gov



ACKNOWLEDGMENTS

This publication was prepared by the Substance Abuse and Mental Health Services Administration (SAMHSA), Office of Applied Studies (OAS) with RTI International under Contract No. 280-03-2602. Judy K. Ball, Ph.D., M.P.A. (DAWN Project Director, SAMHSA/OAS) and Victoria Albright, M.A. (Project Director, RTI) wrote the publication. Other significant contributors included CAPT Kathy M. Poneleit, M.P.H. (SAMHSA/OAS), Erin Mallonee, M.S. (Analyst, RTI), Karol Krotki, Ph.D. (Statistician, RTI), Leyla Stambaugh, Ph.D. (Analyst, RTI), and Peter Frechtel, M.A. (Statistician, RTI). The DAWN data collection was conducted by Westat under Contract No. 283-02-9025 under the direction of Josefina Moran, M.A.

PUBLIC DOMAIN NOTICE

All material appearing in this publication is in the public domain and may be reproduced or copied without permission from the Substance Abuse and Mental Health Services Administration (SAMHSA). However, this publication may not be reproduced or distributed for a fee without the specific, written authorization of the Office of Communications, SAMHSA. Citation of the source is appreciated. Suggested citation:

Substance Abuse and Mental Health Services Administration, Office of Applied Studies. Drug Abuse Warning Network, 2006: National Estimates of Drug-Related Emergency Department Visits. DAWN Series D-30, DHHS Publication No. (SMA) 08-4339, Rockville, MD, 2008.

OBTAINING ADDITIONAL COPIES OF PUBLICATION

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Hard copies may be obtained from http://samhsa.gov/data/copies.cfm.

Or please call SAMHSA's Health Information Network at:

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(English and Español).

ORIGINATING OFFICE

Substance Abuse and Mental Health Services Administration
Office of Applied Studies
1 Choke Cherry Road, Room 7-1044, Rockville, MD 20857
August 2008



CONTENTS

Acknowledgments

Highlights
ED visits involving drug misuse/abuse
Illicit drugs in ED visits
Alcohol and drug-related ED visits
Alcohol in combination with other drugs
Alcohol in patients under age 21
Nonmedical use of pharmaceuticals
Comparisons in drug misuse and abuse: 2004, 2005, and 2006
Special types of drug-related ED visits
Suicide attempts
Seeking detox

Introduction
Major features of DAWN
What is a DAWN case?
What drugs are included in DAWN?
What is covered in this publication?
Hospital participation in 2006
Estimates in this publication
Margin of error for estimates
Comparisons across years
Margin of error for comparisons across years
Estimates adjusted for population size

Drug Misuse and Abuse in ED Visits

Illicit Drugs in ED Visits

Alcohol in ED Visits
Alcohol in combination with other drugs (Tables 5-6, Figure 3)
Alcohol-related ED visits in patients under the age of 21 (Table 7)
ED visits for underage alcohol use (Tables 4, 8, Figure 4)

Nonmedical Use of Pharmaceuticals
Nonmedical use of pharmaceuticals (Tables 9-10, Figure 5)

Comparisons of ED Visits: 2004, 2005, and 2006
Drug misuse and abuse in ED visits (Table 11)
Illicit drugs in ED visits (Table 12)
Alcohol in ED visits (Tables 13-14)
Nonmedical use of pharmaceuticals (Table 15)

Special Types of Drug-Related ED Visits
Suicide attempts (Tables 16-17, Figure 6)
Suicide attempt ED visits: 2004, 2005, and 2006 (Table 18)
Seeking detox (Tables 19-20, Figure 7)
Seeking detox ED visits: 2004, 2005, and 2006 (Table 21)

List of Tables

Table 1. Drug misuse and abuse in ED visits in the U.S., by type of drug involvement: 2006
Table 2. Illicit drugs in ED visits: 2006
Table 3. Illicit drugs, by patient characteristics: 2006
Table 4. Alcohol in drug-related ED visits: 2006
Table 5. Alcohol in combination, by patient and visit characteristics: 2006
Table 6. Drugs most frequently reported with alcohol: 2006
Table 7. Alcohol in drug-related ED visits in patients under age 21: 2006
Table 8. Alcohol only (age < 21), by patient and visit characteristics: 2006
Table 9. Nonmedical use of pharmaceuticals: 2006
Table 10. Nonmedical use of pharmaceuticals, by patient and visit characteristics: 2006
Table 11. Drug misuse and abuse in ED visits in the U.S., by type of drug involvement: 2004, 2005, and 2006
Table 12. Illicit drugs in ED visits: 2004, 2005, and 2006
Table 13. Alcohol in drug-related ED visits: 2004, 2005, and 2006
Table 14. Alcohol in drug-related ED visits in patients under age 21: 2004, 2005, and 2006
Table 15. Nonmedical use of pharmaceuticals ED visits: 2004, 2005, and 2006
Table 16. Suicide attempts: 2006
Table 17. Suicide attempts, by patient and visit characteristics: 2006
Table 18. Suicide attempts: 2004, 2005, and 2006
Table 19. Seeking detox: 2006
Table 20. Seeking detox, by patient and visit characteristics: 2006
Table 21. Seeking detox: 2004, 2005, and 2006

List of Figures

Figure 1. Rates of ED visits involving selected illicit drugs: 2006
Figure 2. Illicit drugs, ED visit rates by age and gender: 2006
Figure 3. Alcohol with other drugs, ED visit rates by age and gender: 2006
Figure 4. Alcohol only (age < 21), ED visit rates by age and gender: 2006
Figure 5. Nonmedical use of pharmaceuticals, ED visit rates by age and gender: 2006
Figure 6. Suicide attempts, ED visit rates by age and gender: 2006
Figure 7. Seeking detox, ED visit rates by age and gender: 2006

List of Appendixes

Appendix A: Multum Lexicon End-User License Agreement
Appendix B: Glossary of Terms
Appendix C: DAWN Data Collection and Statistical Methods
Appendix D: Race and Ethnicity in DAWN

HIGHLIGHTS

This publication presents national estimates of drug-related visits to hospital emergency departments (EDs) for 2006, based on data from the Drug Abuse Warning Network (DAWN). Also presented are comparisons of 2006 estimates with those for 2004 and 2005. DAWN is a public health surveillance system that monitors drug-related ED visits for the Nation and for selected metropolitan areas. DAWN estimates pertain to the entire United States, including Alaska, Hawaii, and the District of Columbia. The Substance Abuse and Mental Health Services Administration (SAMHSA) is the agency responsible for DAWN. SAMHSA is required to collect data on drug-related ED visits under section 505 of the Public Health Service Act.

DAWN relies on a national sample of general, non-Federal hospitals operating 24-hour EDs. The sample is national in scope, with oversampling of hospitals in selected metropolitan areas. In each participating hospital, ED medical records are reviewed retrospectively to find the ED visits that were related to recent drug use. All types of drugs—illegal drugs, prescription and over-the-counter (OTC) pharmaceuticals, dietary supplements, and nonpharmaceutical inhalants—are included. Alcohol, when it is the only drug implicated in a visit, is included for patients younger than age 21; alcohol, when it is present in combination with another drug, is included for patients of all ages.

The 2006 estimates introduce several improvements made to the DAWN sampling and estimation methodology. In order to ensure comparability between estimates for 2004, 2005, and 2006, the improvements were applied retrospectively to 2004 and 2005 data, resulting in small changes as compared to early published estimates.

ED visits involving drug misuse/abuse

In 2006, hospitals in the United States delivered a total of 113 million ED visits, and DAWN estimates that 1,742,887 (confidence interval [CI]: 1,451,086 to 2,034,688)1 ED visits were associated with drug misuse or abuse. Of those ED visits:

Illicit drugs in ED visits

For 2006, DAWN estimates that 958,164 (CI: 690,218 to 1,226,110) ED visits involved an illicit drug. Thus, over half (55%) of all the drug misuse/abuse ED visits during the year involved an illicit drug either alone or in combination with other types of drugs. DAWN estimates that:

Taking the margin of error into account, cocaine was more frequent than any of the other illicit drugs. The stimulants (amphetamines and methamphetamine) were less frequent than marijuana and as frequent as heroin.

After taking population size and the margin of error into account:

Alcohol and drug-related ED visits

For 2006, DAWN estimates that 577,521 (CI: 501,944 to 653,048) ED visits involved either alcohol in combination with another drug (all ages) or alcohol alone for patients under the age of 21. This is about one third (33%) of all drug misuse/abuse ED visits. Since DAWN does not account for ED visits involving alcohol alone in adults, the actual number of ED visits involving alcohol is higher. Alcohol is reported to DAWN when it is present in combination with other drugs, regardless of the patient's age.

Alcohol in combination with other drugs

In 2006, DAWN estimates 450,817 (CI: 383,818 to 517,816) ED visits related to use of alcohol in combination with other drugs. Alcohol was most frequently combined with:

Alcohol in patients under age 21

DAWN estimates 76,760 (CI: 60,318 to 93,202) alcohol-related ED visits for patients aged 12 to 17, and 105,675 (CI: 82,757 to 128,593) alcohol-related ED visits for patients aged 18 to 20. Alcohol is an illegal drug for both of these age groups.

About two thirds (69%) of the alcohol-related ED visits for minors involved alcohol and no other drug. Taking population size and the margin of error into account:

Nonmedical use of pharmaceuticals

For 2006, DAWN estimates that 741,425 (CI: 674,198 to 808,652) ED visits involved nonmedical use of prescription or OTC pharmaceuticals or dietary supplements. The majority of these visits (54%) involved multiple drugs.

Central nervous system (CNS) agents (present in 50% of nonmedical-use visits) and psychotherapeutic agents (44%) were the most frequent drugs reported in the nonmedical-use category of ED visits.

Among the CNS agents, the most frequent drugs were opiate/opioid analgesics (present in 33% of nonmedical-use visits), including single-ingredient formulations (e.g., oxycodone) and combination forms (e.g., hydrocodone with acetaminophen). Methadone, together with single-ingredient and combination forms of oxycodone and hydrocodone, were the most frequent opioids. Once the margin of error is taken into account, these three opioids appeared in similar numbers of visits:

It is not possible to know, based on the documentation available in ED medical records, the extent to which the source of these drugs is a legitimate prescription, as opposed to other sources, nor is it possible to distinguish methadone used for treatment of opiate addiction from the methadone in pill form, which is prescribed for pain. In fact, methadone may be one of the most ambiguous drugs to categorize in DAWN. When a patient on opioid replacement therapy presents to an ED, methadone may be routinely documented in the medical record, but without sufficient detail to distinguish whether the methadone specifically was related to the ED visit.

Among the psychotherapeutic agents, the anxiolytics (anti-anxiety agents), sedatives, and hypnotics were the most frequent, occurring in almost a third (32%) of visits associated with nonmedical use of pharmaceuticals. ED visits involving benzodiazepines clearly outnumber those involving any of the other types of psychotherapeutic agents. DAWN estimates that 195,625 (CI: 167,789 to 223,461) ED visits associated with nonmedical use of pharmaceuticals involved benzodiazepines in 2006.

Taking population size and the margin of error into account:

Comparisons in drug misuse and abuse: 2004, 2005, and 2006

In 2006, hospitals in the United States delivered a total of 113 million ED visits, an increase of 3.9% over 2004. The population of the United States increased 2.9%, from 294 million to 302 million, over the same period.

According to DAWN, the total number of ED visits attributable to drug misuse and abuse was stable across 2004, 2005, and 2006. That is, the apparent difference is within the margin of error. Across the different types of drug involvement, changes were detected for visits involving:

Regarding the significant increases detected, it is worthwhile to consider that the number of pharmaceuticals dispensed for legitimate therapeutic uses may be increasing over time, and DAWN estimates are not adjusted to take such increases into account. Nor do DAWN estimates take into account the increases in the population or in ED use between 2004 and 2006.

No significant changes in ED visits from 2004 to 2006, or from 2005 to 2006, were detected for any of the major illicit drugs (cocaine, heroin, marijuana, and stimulants) or for alcohol.

ED visits related to nonmedical use of pharmaceuticals increased 38% in the period from 2004 to 2006. Among the drugs most frequently implicated in nonmedical use, notable changes from 2004 to 2006 occurred for psychotherapeutic agents (31%) and CNS agents (32%). Within these two categories, visits involving benzodiazepines increased 36%, and visits involving opiate/opioid analgesics increased 43%. Among the opiates/opioids, visits involving hydrocodone/combinations increased 44%, and visits involving oxycodone/combinations increased 56%.

DAWN is not able to assess whether increases or decreases in ED visits associated with specific pharmaceuticals are related to changes in the quantity of these pharmaceuticals being prescribed for therapeutic uses.

Special types of drug-related ED visits

Suicide attempts

DAWN estimates 182,805 (CI: 154,185 to 211,424) ED visits for drug-related suicide attempts in 2006.3 Nearly two thirds (65%) of ED visits for drug-related suicide attempts involved multiple drugs.

In these ED visits for drug-related suicide attempts in 2006:

Overall, there was no significant change in ED visits for drug-related suicide attempts during the time period from 2004 to 2006, but an increase was detected from 2005 to 2006. Increases were evident from 2004 to 2006, as well as 2005 to 2006, for some of the pharmaceuticals frequently involved in suicide attempts, such as benzodiazepines and opiate/opioid pain relievers.

Seeking detox

DAWN estimates 118,355 (CI: 90,171 to 146,540) drug-related ED visits for patients seeking detoxification or substance abuse treatment services during 2006. However, these visits tend to be concentrated in hospitals with administrative policies that require medical clearance in the ED for admission to these specialized units within the hospital. Therefore, these visits do not encompass the full extent of the demand for these services.

Nearly two thirds (65%) of the seeking detox ED visits involved multiple drugs. Illicit drugs and alcohol were common in these visits:

Among the seeking detox ED visits, nearly 7 out of 10 (69%) received some type of follow-up care, either inpatient admission, referral elsewhere for detox or substance abuse treatment services, or transfer to another health care facility. However, more than one quarter (27%) of seeking detox cases might not have received the care they sought, because they were discharged to home.

No significant changes in ED visits from 2004 to 2006, or from 2005 to 2006, were detected for seeking detox ED visits overall, or for alcohol or the illicit drugs involved in these visits.

INTRODUCTION

This publication presents estimates of drug-related emergency department (ED) visits from the Drug Abuse Warning Network (DAWN) for 2006, with comparison of estimates for 2004 and 2005. DAWN is a public health surveillance system that monitors drug-related ED visits for the Nation and for selected metropolitan areas. The Office of Applied Studies (OAS) of the Substance Abuse and Mental Health Services Administration (SAMHSA), U.S. Department of Health and Human Services, has been responsible for DAWN operations since 1992.

Major features of DAWN

What is a DAWN case?

One of the most important features of DAWN is its expansive definition of a case:

A DAWN case is any ED visit related to recent drug use.

To be a DAWN case, the relationship between the ED visit and the drug use need not be causal; the drug needs only to be implicated in the visit. This approach accommodates cases where one or more drugs were involved but may or may not have directly caused the condition generating the ED visit, but at the same time avoids inclusion of current medications that are unrelated. Only recent drug use is included;4 the reason a patient used a drug need not be specified; and the criteria are broad enough to encompass all types of drug-related events, including explicit drug abuse. See Appendix C: DAWN Data Collection and Statistical Methods for a full description of DAWN cases and data collected on those cases.

What drugs are included in DAWN?

DAWN collects data on all types of drugs, including:5

In some cases, the medical record includes only nonspecific drug categories (for instance, "benzodiazepines" or "opiates"). These situations are noted in DAWN publications with the abbreviation "NOS" or "Not Otherwise Specified." In addition, due to the multitude of drugs included in the DAWN drug vocabulary, it is not possible to show all drugs or even all types of drugs in this publication. In these situations, a residual group of drugs may be referred to in a table with the abbreviation "NTA" or "Not Tabulated Above."

What is covered in this publication?

While the full array of drug-related ED visits covered by DAWN is very broad, this publication focuses primarily on ED visits involving drug misuse and abuse. The national estimates of ED visits associated with drug misuse and abuse are presented in terms of the following three categories:

The illicit drugs category covers ED visits involving the use of substances that are generally illegal. The alcohol category includes alcohol used in combination with other drugs and alcohol used alone in patients under 21, but excludes alcohol used alone in patients aged 21 and over. Nonmedical use of pharmaceuticals includes ED visits related to the misuse or abuse of prescription or OTC medications or dietary supplements. Nonmedical use includes taking a higher than prescribed or recommended dose of a pharmaceutical (i.e., contrary to directions or labeling), taking a pharmaceutical prescribed for another individual, malicious poisoning of the patient by another individual, and substance abuse involving pharmaceuticals.8

In addition, this report includes a separate section on two special types of ED visits: drug-related suicide attempts and patients "seeking detox." The latter includes patients who present to the ED seeking detoxification services or entry into a substance abuse treatment program. These visits tend to be concentrated in hospitals with administrative practices requiring medical clearance in the ED for admission to detox or substance abuse treatment units within the hospital. Drug-related ED visits involving suicide attempts or seeking detox are excluded from the category of nonmedical use of pharmaceuticals.

Hospital participation in 2006

For 2006, 205 hospitals submitted data that were used for estimation. The overall weighted response rate was 26.1%. For the 12 oversampled metropolitan areas and divisions, the individual response rates ranged from 30.8% in the Houston metropolitan area to 71.2% in the Detroit metropolitan area. Additional detail on response rates is provided in Appendix C.

DAWN cases are found through a retrospective review of medical records in participating hospitals. Across all participating hospitals in 2006, 9.8 million charts were reviewed to find the drug-related ED visits that met the DAWN case criteria. Based on the review of charts, 346,946 drug-related visits were found and submitted. On average, a DAWN member hospital submitted 1,077 DAWN cases. However, the number of submitted cases varied widely across hospitals, from 7 cases to 6,782 cases (median 820) in a single hospital during 2006.

Estimates in this publication

Estimates in this publication were calculated by applying sampling weights, nonresponse adjustments, and poststratification adjustments to data from the probability sample of hospitals. Only national estimates pertaining to the entire United States—50 States and the District of Columbia—are provided in this publication.

Hospitals eligible for the DAWN sample are non-Federal, short-stay, general medical and surgical hospitals in the United States that operate 24-hour EDs. The American Hospital Association's (AHA) 2001 Annual Survey is the source of the sampling frame. Subsequent AHA surveys are used annually to refresh the sample. For a definition of sampling frame and other technical terms used in this publication, see Appendix B: Glossary of Terms.

The DAWN sample of hospitals includes an oversampling of hospitals in selected metropolitan areas (referred to as oversample areas), supplemented with a sample of hospitals from the remainder of the United States, which includes other metropolitan areas, as well as nonmetropolitan and rural areas. The metropolitan area boundaries correspond to the definitions issued by the Office of Management and Budget (OMB) in June 2003. National estimates are calculated as the sum of the estimates from oversample areas plus the estimate for the remainder of the United States after taking into account nonresponse, the volume of ED visits delivered by the universe of eligible hospitals in each area, and data quality factors. A more detailed discussion of the DAWN sample of hospitals and estimation procedures is provided in Appendix C.

Margin of error for estimates

Since DAWN relies on a sample of hospitals, each estimate produced from the DAWN ED data is subject to sampling variability, referred to as the "margin of error." This is the variation in the estimate that would be observed naturally if different samples were drawn from the same population using the same procedures. The sampling variability of an estimate in this publication is measured by its relative standard error (RSE). The precision of an estimate is inversely related to its sampling variability, as measured by the RSE: the greater the RSE, the lower the precision.

DAWN estimates with RSE values greater than 50% and quantities less than 30 are regarded as too imprecise for publication and are not shown. Three periods ("…") are displayed in the place of suppressed estimates. Ratios (percentages or rates per 100,000 population) based on suppressed estimates are likewise suppressed. Gray shading in a cell indicates that the cell is not applicable. For example, drugs other than alcohol cannot be present in an "alcohol-only" category.

In this publication, 95% confidence intervals (CIs) are included in many of the tables and are cited in the text along with the estimates. A 95% CI means that if repeated samples were drawn from the same population of hospitals using the same sampling and data collection procedures, the true population value would fall within the confidence interval 95% of the time. A CI, which is expressed as a range of values, is useful because the interval reflects both the estimate and its particular margin of error.

For readers unfamiliar with these statistical concepts, additional descriptions and examples are provided in Appendix C.

Comparisons across years

In this publication, between-year changes are assessed by comparing estimates for 2006 to those for 2004 and to those for 2005.

Major changes to DAWN were instituted at the beginning of 2003 as the result of a redesign that altered most of DAWN's core features. Changes included the design of the hospital sample, the drug-related cases eligible for DAWN, the data items submitted on these cases, and the protocol for case finding and quality assurance. These improvements created a permanent disruption in trends. As a result, comparisons cannot be made between old DAWN (2002 and prior years) and the redesigned DAWN (2004 and forward).9

Margin of error for comparisons across years

DAWN analysts tested each set of estimates between two years to ascertain if the difference exceeded its margin of error. To be reported in this publication as a change, the difference between estimates for two years must be statistically significant, that is, the difference must exceed the margin of error. Differences that are not statistically significant indicate that there was no real change between the two years. Appendix C provides additional detail on the method of testing for significant differences between estimates for different years.

Estimates adjusted for population size

Standardized measures are needed to make valid comparisons of ED visits across age and gender categories that differ in population size. For age in particular, the size of the underlying population differs considerably across age groups; for example, the number of individuals aged 18 to 20 in the United States is much lower than the number of individuals aged 35 to 44.

This publication reports rates of ED visits per 100,000 persons for unsuppressed estimates. Rates are generated using population data from the U.S. Bureau of the Census.10 An example of how these rates are generated and the 2006 population estimates used for this publication are found in Appendix C.

Standardized rates are not calculated for race and ethnicity subgroups, because the race and ethnicity categories available to DAWN are much less detailed and contain considerably more missing data than the race and ethnicity categories in the Census data. Appendix D: Race and Ethnicity in DAWN, describes the race and ethnicity data reported to DAWN.

DRUG MISUSE AND ABUSE IN ED VISITS

For 2006, DAWN estimates that over 1.7 million ED visits were associated with drug misuse or abuse (Table 1). This estimate includes:

Of the 1.7 million drug misuse/abuse visits, about two thirds (66%) were associated with a single drug type (illicit drugs, alcohol, or nonmedical use of pharmaceuticals). ED visits involving illicit drugs alone accounted for 31% of all visits related to drug misuse/abuse in 2006. ED visits involving nonmedical use of pharmaceuticals alone accounted for another 28%. About 7% of drug misuse/abuse visits were related to consumption of alcohol (and no other drug) by a minor.12 The remaining visits (34%) involved some combination of illicit drugs, alcohol, and/or nonmedical use of pharmaceuticals.

This does not suggest that the majority of ED drug misuse/abuse visits involved a single drug. In fact, the typical drug-related ED visit involves multiple drugs, but these may be of a common type. For example, an ED visit involving illicit drugs alone often involves more than one illicit drug (e.g., cocaine and heroin).

ED visits in each of the three major categories—illicit drugs, alcohol, and nonmedical use of pharmaceuticals—are discussed in greater detail in separate sections of this publication.

Table 1
Drug misuse and abuse in ED visits in the U.S., by type of drug involvement: 2006
Drug involvement1 Estimated
visits2
Percent
of visits
Relative
standard
error (RSE)
95% Confidence interval
Lower
bound
- Upper
bound
1 The classification of drugs used in DAWN is derived from the Multum Lexicon, © 2007, Multum Information Services, Inc. The classification was modified to meet DAWN's unique requirements (2007). The Multum Licensing Agreement governing use of the Lexicon is provided in Appendix A and can be found on the Internet at http://www.multum.com.
2 These are estimates of ED visits based on a representative sample of non-Federal, short-stay hospitals with 24-hour EDs in the United States.
3 DAWN excludes alcohol-only visits for adults. Alcohol, when present with other drugs, is included for all ages.
SOURCE: Office of Applied Studies, SAMHSA, Drug Abuse Warning Network, 2006 (03/2008 update).
All types of drug misuse/abuse 1,742,887 100%   8.5 1,451,086 - 2,034,688
Illicit drugs only    536,554   31% 18.3 343,920 - 729,189
Alcohol only (age < 21)    126,704     7% 12.5 95,766 - 157,642
Pharmaceuticals only    486,276   28%   5.8 430,721 - 541,832
Combinations            
Illicit drugs with alcohol3    219,521   13% 13.5 161,230 - 277,812
Illicit drugs with pharmaceuticals    142,535     8% 10.4 113,561 - 171,510
Alcohol with pharmaceuticals    171,743   10%   5.8 152,240 - 191,246
Illicit drugs with alcohol and pharmaceuticals      59,553     3%   9.8 48,079 - 71,028

ILLICIT DRUGS IN ED VISITS

To better understand the role of specific drugs and types of drugs in ED visits, this publication provides more detailed analysis of three drug categories: illicit drugs, alcohol, and nonmedical use of pharmaceuticals. This section focuses on ED visits involving illicit drugs.

For 2006, DAWN estimates that 958,164 (CI: 690,218 to 1,226,110) ED visits involved an illicit drug (Table 2). Thus, over half (55%) of all the drug misuse/abuse ED visits during the year involved illicit drugs, either alone or in combination with another drug type.

DAWN estimates that cocaine was involved in 548,608 (CI: 374,579 to 722,636) ED visits. In other words, close to one in three drug misuse/abuse ED visits (31%) involved cocaine.

Marijuana was involved in 290,563 (CI: 238,737 to 342,388) ED visits. Although it was associated with the second highest number of drug misuse/abuse ED visits for illicit drugs, marijuana was involved in approximately half as many ED visits as cocaine.

Heroin was involved in 189,780 (CI: 119,525 to 260,035) ED visits, or approximately 11% of drug misuse/abuse ED visits overall. This is likely an underestimate, though, because some portion of heroin use has been unavoidably classified as an "unspecified opiate." Heroin is an opiate, and some drug screens test for opiates only as a class. Nearly two thirds (64%) of reports of "opiates" submitted to DAWN for 2006 came from toxicology findings, so some unknown quantity of these may have been heroin. The number of drug misuse/abuse ED visits involving unspecified opiates is estimated at 55,674 (CI: 42,590 to 68,757) visits.

Stimulants, including amphetamines and methamphetamine, were involved in 107,575 (CI: 66,105 to 149,046) ED visits, about 6% of drug misuse/abuse ED visits. Amphetamines and methamphetamine are combined for this analysis because some drug screens test for amphetamines only as a class. Consequently, an amphetamine-positive result could indicate amphetamine or methamphetamine. Nearly all (99%) of the reports of amphetamines submitted to DAWN came simply as "amphetamine" and 65% of those were derived from toxicology findings.

Other illicit drugs appeared at much lower frequencies. For 2006, DAWN estimates:

Table 2
Illicit drugs in ED visits: 2006
Drug category and selected drugs1 Estimated visits2,3,4 Relative standard error (RSE) 95% Confidence interval
Lower
bound
- Upper
bound
1 The classification of drugs used in DAWN is derived from the Multum Lexicon, © 2007, Multum Information Services, Inc. The classification was modified to meet DAWN's unique requirements (2007). The Multum Licensing Agreement governing use of the Lexicon is provided in Appendix A and can be found on the Internet at http://www.multum.com.
2 These are estimates of ED visits based on a representative sample of non-Federal, short-stay hospitals with 24-hour EDs in the United States.
3 ED visits often involve multiple drugs. Such visits will appear multiple times in this table (e.g., a visit involving both cocaine and heroin will appear twice in this table). Summing ED visits as reported will produce incorrect and inflated counts of ED visits.
4 Three dots (…) indicate that an estimate with an RSE greater than 50% or an estimate less than 30 has been suppressed.
SOURCE: Office of Applied Studies, SAMHSA, Drug Abuse Warning Network, 2006 (03/2008 update).
Drug-related ED visits
Total drug misuse/abuse ED visits 1,742,887   8.5 1,451,086 - 2,034,688
ED visits, illicit drugs    958,164 14.3 690,218 - 1,226,110
Cocaine    548,608 16.2 374,579 - 722,636
Heroin    189,780 18.9 119,525 - 260,035
Marijuana    290,563   9.1 238,737 - 342,388
Stimulants    107,575 19.7 66,105 - 149,046
Amphetamines      32,240 11.4 25,034 - 39,446
Methamphetamine      79,924 25.1 40,653 - 119,194
MDMA (Ecstasy)      16,749 16.1 11,470 - 22,029
GHB        1,084 26.7 517 - 1,652
Flunitrazepam (Rohypnol)             …    … -
Ketamine           270 45.6 29 - 511
LSD        4,002 26.2 1,945 - 6,059
PCP      21,960 38.2 5,518 - 38,403
Miscellaneous hallucinogens        3,898 17.1 2,591 - 5,205
Inhalants        5,643 15.9 3,886 - 7,400
Combinations not tabulated above (NTA)        2,055 26.0 1,007 - 3,103
Drug category and selected drugs1 ED visits
per 100,000
population2,3,4
Relative standard error (RSE) 95% Confidence interval
Lower
bound
- Upper
bound
ED visits per 100,000 population
Total drug misuse/abuse ED visits       576.7   8.5 480.1 - 673.2
ED visits, illicit drugs       317.0 14.3 228.4 - 405.7
Cocaine       181.5 16.2 123.9 - 239.1
Heroin         62.8 18.9 39.5 - 86.0
Marijuana         96.1   9.1 79.0 - 113.3
Stimulants         35.6 19.7 21.9 - 49.3
Amphetamines         10.7 11.4 8.3 - 13.1
Methamphetamine         26.4 25.1 13.5 - 39.4
MDMA (Ecstasy)           5.5 16.1 3.8 - 7.3
GHB           0.4 26.7 0.2 - 0.5
Flunitrazepam (Rohypnol)             …    … -
Ketamine           0.1 45.6 0.0 - 0.2
LSD           1.3 26.2 0.6 - 2.0
PCP           7.3 38.2 1.8 - 12.7
Miscellaneous hallucinogens           1.3 17.1 0.9 - 1.7
Inhalants           1.9 15.9 1.3 - 2.4
Combinations not tabulated above (NTA)           0.7 26.0 0.3 - 1.0

When considered in relation to the population of the United States, ED visits associated with illicit drugs vary across major drugs of abuse (Figure 1):

Figure 1
Rates of ED visits involving selected illicit drugs: 2006

Figure 1   D

SOURCE: Office of Applied Studies, SAMHSA, Drug Abuse Warning Network, 2006 (03/2008 update).

The rates of ED visits involving cocaine, marijuana, and heroin were higher for males than for females, after taking population size and the margin of error into account, but there was not a gender difference for stimulants (Figure 2). For cocaine the rates per 100,000 population were highest among patients aged 18 to 54, with lower rates for younger and older patients (Table 3, Figure 2). For heroin, the rates were highest for patients aged 21 to 54, while the rates for marijuana were highest for patients aged 18 to 24, and the rates for stimulants were highest for patients aged 18 to 44.

In terms of race/ethnicity, 44% of the visits related to any illicit drug use involved patients who were white. However, evaluating the relative frequencies across the race/ethnicity groups is impeded by missing data; race/ethnicity was unknown in 11% of illicit drug-related visits overall, and the percentage was higher for some drugs (e.g., 13% for heroin and 20% for stimulants).

Table 3
Illicit drugs, by patient characteristics: 2006
Patient characteristics Selected drugs1
All
illicits
Cocaine Heroin Marijuana Stimulants MDMA
(Ecstasy)
GHB LSD PCP
1 The classification of drugs used in DAWN is derived from the Multum Lexicon, © 2007, Multum Information Services, Inc. The classification was modified to meet DAWN's unique requirements (2007). The Multum Licensing Agreement governing use of the Lexicon is provided in Appendix A and can be found on the Internet at http://www.multum.com.
2 These are estimates of ED visits based on a representative sample of non-Federal, short-stay hospitals with 24-hour EDs in the United States.
3 Three dots (…) indicate that an estimate with an RSE greater than 50% or an estimate less than 30 has been suppressed.
SOURCE: Office of Applied Studies, SAMHSA, Drug Abuse Warning Network, 2006 (03/2008 update).
Drug-related ED visits2,3
ED visits, illicit drugs 958,164 548,608 189,780 290,563 107,575 16,749 1,084 4,002 21,960
Gender                  
Male 631,052 354,268 129,914 195,063   68,638 10,835    824 3,297 15,298
Female 326,846 194,121   59,744   95,478   38,930   5,915    261    705   6,661
Unknown        266          …           …           …           …         …     …     …        …
Age                  
0-5 years        855        585           …           …           …         …     …     …        …
6-11 years          …          …           …           …           …         …     …     …        …
12-17 years   58,428   10,984     1,661   44,088     7,740   4,524     … 1,045   1,242
18-20 years   71,973   26,802     8,299   44,146     8,487   3,997     … 1,075   1,718
21-24 years 105,043   47,515   17,119   46,388   16,453   4,217     …    611   5,118
25-29 years 126,699   63,945   26,607   42,626   20,489   1,928    121     …   5,637
30-34 years 107,718   67,820   23,657   28,904   15,000   1,124    175     …   2,714
35-44 years 264,430 181,912   57,155   49,571   26,170      417     …     …   3,088
45-54 years 176,026 122,028   42,662   26,367   10,068         …     …     …   2,271
55-64 years   39,767   23,177   11,049     6,947     2,680         …     …     …        …
65 years and older     5,929     3,499     1,456     1,071           …         …     …     …        …
Unknown        388        300           …          68           …         …     …     …        …
Race/ethnicity                  
White 421,775 215,718   78,470 154,081   57,582   8,140    720 2,898   6,087
Black 295,041 213,797   49,522   75,835     6,638   4,392     …     …        …
Hispanic 126,529   63,692   35,781   31,528           …   1,528     …     …        …
Race/ethnicity not tabulated above (NTA)     7,830     3,206     1,656     1,871     1,893        90     …     …        …
Unknown 106,990   52,194   24,351   27,248   21,658         …    130     …   1,625
ED visits per 100,000 population2,3
ED visits, illicit drugs     317.0     181.5       62.8       96.1       35.6       5.5     0.4     1.3       7.3
Gender                  
Male     423.5     237.8       87.2     130.9       46.1       7.3     0.6     2.2     10.3
Female     213.3     126.7       39.0       62.3       25.4       3.9     0.2     0.5       4.3
Age                  
0-5 years         3.5         2.4           …           …           …         …     …     …        …
6-11 years          …          …           …           …           …           …     …     …        …
12-17 years     229.6       43.2         6.5     173.3       30.4     17.8     …     4.1       4.9
18-20 years     567.9     211.5       65.5     348.3       67.0     31.5     …     8.5     13.6
21-24 years     618.7     279.9     100.8     273.2       96.9     24.8     …     3.6     30.1
25-29 years     597.0     301.3     125.4     200.9       96.5       9.1     0.6     …     26.6
30-34 years     548.0     345.0     120.4     147.1       76.3       5.7     0.9     …     13.8
35-44 years     610.7     420.1     132.0     114.5       60.4       1.0     …     …       7.1
45-54 years     400.7     277.8       97.1       60.0       22.9           …     …     …       5.2
55-64 years     121.5       70.8       33.7       21.2         8.2           …     …     …        …
65 years and older       15.7         9.2         3.8         2.8           …           …     …     …        …

Figure 2
Illicit drugs, ED visit rates by age and gender: 2006

Figure 2   D

SOURCE: Office of Applied Studies, SAMHSA, Drug Abuse Warning Network, 2006 (03/2008 update).

ALCOHOL IN ED VISITS

Among all the drugs collected by DAWN, alcohol is unique. An ED visit related to alcohol use qualifies as a DAWN case under only two conditions: (1) the alcohol is found in combination with other drugs, regardless of patient age; or (2) the alcohol is found alone (i.e., not in combination with other drugs) in a patient under the age of 21. ED visits associated with alcohol use, particularly among underage patients, represent a significant public health and policy concern and are examined in detail in this section.

For 2006, DAWN estimates that 577,521 (CI: 501,994 to 653,048) ED visits involved either alcohol in combination with another drug (all ages) or alcohol alone for patients under the age of 21. This is about one third (33%) of all drug misuse/abuse ED visits (Table 4). Of all these ED visits involving alcohol, about one fifth (22%) involved patients under the age of 21 who used alcohol alone, that is, with no other drug.

Table 4
Alcohol in drug-related ED visits: 2006
Drug category and selected drugs1 Estimated visits2,3 Relative standard error (RSE) 95% Confidence interval
Lower
bound
- Upper
bound
1 The classification of drugs used in DAWN is derived from the Multum Lexicon, © 2007, Multum Information Services, Inc. The classification was modified to meet DAWN's unique requirements (2007). The Multum Licensing Agreement governing use of the Lexicon is provided in Appendix A and can be found on the Internet at http://www.multum.com.
2 These are estimates of ED visits based on a representative sample of non-Federal, short-stay hospitals with 24-hour EDs in the United States.
3 Estimates are all expressed in visits.
SOURCE: Office of Applied Studies, SAMHSA, Drug Abuse Warning Network, 2006 (03/2008 update).
Total drug misuse/abuse ED visits 1,742,887   8.5 1,451,086 - 2,034,688
ED visits, alcohol    577,521   6.7 501,994 - 653,048
Alcohol in combination    450,817   7.6 383,818 - 517,816
Alcohol alone    126,704 12.5 95,766 - 157,642

Alcohol in combination with other drugs (Tables 5-6, Figure 3)

DAWN estimates 450,817 (CI: 383,818 to 517,816) ED visits related to use of alcohol in combination with another drug(s) in 2006. Alcohol in combination with other drugs is reported to DAWN regardless of the patient's age. These are the only alcohol reports received for patients aged 21 and older. It is these adult patients who account for nearly 9 out of 10 ED visits (87%) implicating alcohol with another drug (Table 5).

Males accounted for 63% of visits involving alcohol in combination with other drugs (Table 5). Taking population size and the margin of error into account, males had higher rates of such visits than females (Figure 3). There was little variation in rates across the age groups from ages 18 to 54. ED visit rates were lower for older and younger patients.

In terms of race/ethnicity, 57% of the visits with alcohol in combination involved patients who were white. Evaluating the relative frequencies across the race/ethnicity groups is impeded by missing data; in 10% of visits race/ethnicity was unknown.

Table 5
Alcohol in combination, by patient and visit characteristics: 2006
Patient characteristics Estimated visits1,2 Visit characteristics Estimated visits1,2
1 These are estimates of ED visits based on a representative sample of non-Federal, short-stay hospitals with 24-hour EDs in the United States.
2 Three dots (…) indicate that an estimate with an RSE greater than 50% or an estimate less than 30 has been suppressed.
SOURCE: Office of Applied Studies, SAMHSA, Drug Abuse Warning Network, 2006 (03/2008 update).
ED visits, alcohol in combination 450,817    
Gender   Number of drugs involved  
Male 284,425 Single drug  
Female 166,278 Multiple drugs 450,817
Unknown           … Alcohol involved 450,817
Age   Disposition  
0-5 years           … Treated and released 234,061
6-11 years           … Discharged home 192,114
12-17 years   24,418 Released to police/jail   15,664
18-20 years   31,702 Referred to detox/treatment   26,283
21-24 years   44,914 Admitted to this hospital 155,708
25-29 years   53,936 ICU/critical care   35,474
30-34 years   44,304 Surgery        429
35-44 years 133,489 Chemical dependency/detox   12,935
45-54 years   88,078 Psychiatric unit   49,858
55-64 years   21,915 Other inpatient unit   57,011
65 years and older     7,453 Other disposition   61,048
Unknown        175 Transferred   40,915
Race/ethnicity   Left against medical advice     8,977
White 256,104 Died           …
Black   95,003 Other           …
Hispanic   51,076 Not documented     2,791
Race/ethnicity not tabulated above (NTA)     4,240    
Unknown   44,394    

Figure 3
Alcohol with other drugs, ED visit rates by age and gender: 2006

Figure 3   D

SOURCE: Office of Applied Studies, SAMHSA, Drug Abuse Warning Network, 2006 (03/2008 update).

Alcohol was most frequently combined with (Table 6):

Table 6
Drugs most frequently reported with alcohol: 2006
Drugs reported with alcohol1 Estimated visits2
1 The classification of drugs used in DAWN is derived from the Multum Lexicon, © 2007, Multum Information Services, Inc. The classification was modified to meet DAWN's unique requirements (2007). The Multum Licensing Agreement governing use of the Lexicon is provided in Appendix A and can be found on the Internet at http://www.multum.com.
2 These are estimates of ED visits based on a representative sample of non-Federal, short-stay hospitals with 24-hour EDs in the United States.
SOURCE: Office of Applied Studies, SAMHSA, Drug Abuse Warning Network, 2006 (03/2008 update).
No other drug 126,704
Cocaine only 101,588
Marijuana only   41,653
Cocaine and marijuana only   21,241
Heroin only   14,958
Stimulants only     7,895
Alprazolam only     8,007
Cocaine and heroin only   10,628

Alcohol-related ED visits in patients under the age of 21 (Table 7)

For individuals under age 21, alcohol is an illegal drug, and ED visits related to both alcohol alone and alcohol in combination are reported to DAWN for this age group. Considering alcohol alone and alcohol in combination with other drugs, DAWN estimates:

Nearly 7 in 10 (69%) of the alcohol-related ED visits for minors involved alcohol alone, a finding that is similar for patients aged 12 to 17 and patients aged 18 to 20 (Table 7).

Table 7
Alcohol in drug-related ED visits in patients under age 21: 2006
Drug category and selected drugs1 Estimated
visits2
Relative
standard
error (RSE)
95% Confidence interval
Lower
bound
- Upper
bound
1 The classification of drugs used in DAWN is derived from the Multum Lexicon, © 2007, Multum Information Services, Inc. The classification was modified to meet DAWN's unique requirements (2007). The Multum Licensing Agreement governing use of the Lexicon is provided in Appendix A and can be found on the Internet at http://www.multum.com.
2 These are estimates of ED visits based on a representative sample of non-Federal, short-stay hospitals with 24-hour EDs in the United States.
SOURCE: Office of Applied Studies, SAMHSA, Drug Abuse Warning Network, 2006 (03/2008 update).
Patients aged 12-17
ED visits, alcohol   76,760 10.9 60,318 - 93,202
Alcohol in combination   24,418   9.0 20,134 - 28,703
Alcohol alone   52,342 14.6 37,323 - 67,360
Patients aged 18-20
ED visits, alcohol 105,675 11.1 82,757 - 128,593
Alcohol in combination   31,702   8.9 26,193 - 37,211
Alcohol alone   73,973 14.1 53,502 - 94,444

ED visits for underage alcohol use (Tables 4, 8, Figure 4)

For 2006, DAWN estimates 126,704 (CI: 95,766 to 157,642) ED visits related to use of alcohol alone (i.e., not in combination with another drug) by patients who were younger than age 21 (Table 4). Nearly all (99%, or 125,888 visits) of those visits represent underage drinking that was not related to either a suicide attempt or a request for admission to detox or substance abuse treatment program (Table 8).

Taking population size into account, the rate of these alcohol-only ED visits for patients aged 18 to 20 (581 visits per 100,000 population) was 2.8 times that for patients aged 12 to 17 (204 per 100,000). Males and females had similar rates (Figure 4).

In terms of race/ethnicity, 58% of these alcohol-only visits involved patients who were white. Evaluating the relative frequencies of the race/ethnicity groups is impeded by missing data; in 16% of visits, race/ethnicity was unknown (Table 8).

Most (90%) of the alcohol-only ED visits resulted in patients' being treated and released, usually to home; another 6% were admitted to inpatient units (Table 8).

Table 8
Alcohol only (age < 21), by patient and visit characteristics: 2006
Patient characteristics Estimated
visits1,2
Visit characteristics Estimated
visits1,2
1 These are estimates of ED visits based on a representative sample of non-Federal, short-stay hospitals with 24-hour EDs in the United States.
2 Three dots (…) indicate that an estimate with an RSE greater than 50% or an estimate less than 30 has been suppressed.
3 This table is limited to ED visits classified as "alcohol only (age < 21)" and excludes visits classified as either "suicide attempt" or "seeking detox." Therefore, the estimate of total visits is slightly lower than reported in Table 4.
SOURCE: Office of Applied Studies, SAMHSA, Drug Abuse Warning Network, 2006 (03/2008 update).
ED visits, alcohol only (age < 21)3 125,888    
Gender   Number of drugs involved  
Male   71,306 Single drug 125,888
Female   54,574 Multiple drugs  
Unknown           … Alcohol involved 125,888
Age   Disposition  
0-5 years           … Treated and released 112,671
6-11 years           … Discharged home 102,839
12-17 years   51,901 Released to police/jail     7,870
18-20 years   73,598 Referred to detox/treatment     1,962
21-24 years   Admitted to this hospital     7,479
25-29 years   ICU/critical care     1,123
30-34 years   Surgery          90
35-44 years   Chemical dependency/detox           …
45-54 years   Psychiatric unit        943
55-64 years   Other inpatient unit     5,197
65 years and older   Other disposition     5,738
Unknown   Transferred     3,506
Race/ethnicity   Left against medical advice        688
White   73,624 Died           …
Black     7,427 Other     1,032
Hispanic   23,602 Not documented        501
Race/ethnicity not tabulated above (NTA)     1,709    
Unknown   19,526    

Figure 4
Alcohol only (age < 21), ED visit rates by age and gender: 2006

Figure 4   D

SOURCE: Office of Applied Studies, SAMHSA, Drug Abuse Warning Network, 2006 (03/2008 update).

NONMEDICAL USE OF PHARMACEUTICALS

Use of illicit drugs is, by definition, substance abuse. For pharmaceuticals, however, distinguishing medical from nonmedical use is more complicated.13 In DAWN, "medical use" means taking a prescription or over-the-counter (OTC) pharmaceutical as prescribed or recommended, and "nonmedical use" is use that does not meet the definition of medical use.14 Thus, nonmedical use of pharmaceuticals includes taking more than the prescribed dose of a prescription pharmaceutical or more than the recommended dose of an OTC pharmaceutical or supplement; taking a pharmaceutical prescribed for another individual; deliberate poisoning with a pharmaceutical by another person; and documented misuse or abuse of a prescription or OTC pharmaceutical or dietary supplement. Nonmedical use of pharmaceuticals may involve pharmaceuticals alone or pharmaceuticals in combination with illicit drugs or alcohol.

A cautionary note: DAWN tries to capture only drugs that are related to the ED visit and actively discourages reporting of current medications that are unrelated to the visit. It is important to understand, however, that it is not possible, given the limitations of medical record documentation, to eliminate completely the reporting of current medications, and this should be considered when one interprets these findings. Also, it is not possible to know, based on the documentation available in ED medical records, the extent to which pharmaceuticals came from legitimate prescriptions versus other sources.

Nonmedical use of pharmaceuticals (Tables 9-10, Figure 5)

For 2006, DAWN estimates that 741,425 (CI: 674,198 to 808,652) ED visits involved nonmedical use of prescription or OTC pharmaceuticals or dietary supplements (Table 9). The majority of these visits (54%) involved multiple drugs (Table 10):

Central nervous system (CNS) agents (50% of nonmedical-use visits) and psychotherapeutic agents (44%) were the most frequent drugs reported in the nonmedical-use category of ED visits (Table 9). Respiratory agents (4%), cardiovascular agents (5%), and all other types of pharmaceuticals were much less frequent.

Among the CNS agents, the most frequent drugs were opiate/opioid analgesics (33% of nonmedical-use visits), including single-ingredient formulations (e.g., oxycodone) and combination forms (e.g., hydrocodone with acetaminophen). Methadone, together with single-ingredient and combination forms of oxycodone and hydrocodone, were the most frequent opioids. Once the margin of error is taken into account, these three opioids appeared in similar numbers of visits:

Table 9
Nonmedical use of pharmaceuticals: 2006
Selected drug categories and selected drugs1 Estimated visits2,3,4 Relative standard error (RSE) 95% Confidence interval
Lower bound - Upper bound
1 The classification of drugs used in DAWN is derived from the Multum Lexicon, © 2007, Multum Information Services, Inc. The classification was modified to meet DAWN's unique requirements (2007). The Multum Licensing Agreement governing use of the Lexicon is provided in Appendix A and can be found on the Internet at http://www.multum.com.
2 These are estimates of ED visits based on a representative sample of non-Federal, short-stay hospitals with 24-hour EDs in the United States.
3 ED visits often involve multiple drugs. Such visits will appear multiple times in this table (e.g., a visit involving oxycodone and hydrocodone will appear twice in this table). Summing ED visits as reported will produce incorrect and inflated counts of ED visits.
4 Three dots (…) indicate that an estimate with an RSE greater than 50% or an estimate less than 30 has been suppressed.
SOURCE: Office of Applied Studies, SAMHSA, Drug Abuse Warning Network, 2006 (03/2008 update).
ED visits, nonmedical use 741,425   4.6 674,198 - 808,652
PSYCHOTHERAPEUTIC AGENTS 323,999   4.2 297,495 - 350,504
Antidepressants   79,682   8.7 66,026 - 93,338
MAO inhibitors           …     … -
SSRI antidepressants   35,370 14.6 25,248 - 45,491
Tricyclic antidepressants   16,564 17.6 10,844 - 22,285
Miscellaneous antidepressants     7,561 28.5 3,344 - 11,778
Antipsychotics   44,733   8.7 37,080 - 52,387
Anxiolytics, sedatives, and hypnotics 233,875   5.8 207,294 - 260,457
Barbiturates   10,991 18.2 7,068 - 14,913
Benzodiazepines 195,625   7.3 167,789 - 223,461
Alprazolam   65,236 11.2 50,911 - 79,561
Clonazepam   33,557 12.1 25,580 - 41,534
Diazepam   19,936   9.8 16,108 - 23,764
Lorazepam   23,720 10.0 19,079 - 28,361
Benzodiazepines NOS   58,348 21.7 33,575 - 83,120
Misc. anxiolytics, sedatives, and hypnotics   40,626 10.5 32,304 - 48,947
Diphenhydramine   12,291 11.0 9,643 - 14,939
Hydroxyzine     2,678 17.7 1,749 - 3,606
Zolpidem   17,257 16.6 11,633 - 22,882
Anxiolytics, sedatives, and hypnotics NOS     3,629 14.5 2,601 - 4,657
CNS stimulants   13,892 16.5 9,401 - 18,383
Amphetamine-dextroamphetamine     5,027 26.9 2,377 - 7,677
Caffeine     4,407 22.0 2,509 - 6,305
Dextroamphetamine           …     … -
Methylphenidate     2,192 28.2 980 - 3,404
CENTRAL NERVOUS SYSTEM AGENTS 373,138   5.4 333,720 - 412,556
Analgesics 323,579   5.5 288,441 - 358,717
Antimigraine agents     1,191 29.2 509 - 1,873
Cox-2 inhibitors           … 68.9 -
Opiates/opioids 247,669   6.9 214,160 - 281,177
Opiates/opioids, unspecified   50,978 12.6 38,416 - 63,540
Narcotic analgesics 201,280   8.2 168,954 - 233,606
Buprenorphine/combinations     4,440 41.6 823 - 8,057
Codeine/combinations     6,928 18.4 4,433 - 9,424
Fentanyl/combinations   16,012 27.3 7,441 - 24,583
Hydrocodone/combinations   57,550 12.3 43,701 - 71,398
Hydromorphone/combinations     6,780 23.6 3,649 - 9,911
Meperidine/combinations     1,440 38.7 349 - 2,532
Methadone   45,130 10.5 35,870 - 54,389
Morphine/combinations   20,416 14.2 14,750 - 26,082
Oxycodone/combinations   64,888 11.9 49,746 - 80,030
Propoxyphene/combinations     6,220 18.6 3,955 - 8,485
Nonsteroidal anti-inflammatory agents   27,662   8.9 22,846 - 32,479
Ibuprofen   20,541   8.6 17,071 - 24,011
Naproxen     6,651 17.9 4,314 - 8,987
Salicylates/combinations   10,399 14.5 7,444 - 13,354
Miscellaneous analgesics/combinations   54,313   7.9 45,938 - 62,687
Acetaminophen/combinations   44,314   9.0 36,482 - 52,146
Tramadol/combinations     6,048 16.2 4,128 - 7,969
Tramadol     5,961 16.4 4,050 - 7,873
Acetaminophen-tramadol           …           … -
Analgesic combinations not tabulated above (NTA)        898 30.8 355 - 1,441
Anorexiants     1,168 28.2 522 - 1,815
Anticonvulsants   31,169 13.2 23,099 - 39,238
Antiemetic/antivertigo agents     1,360 32.6 491 - 2,230
Anti-Parkinson agents     3,816 31.5 1,457 - 6,174
General anesthetics           …           … -
Muscle relaxants   38,918 16.5 26,325 - 51,510
Carisoprodol   24,505 23.2 13,352 - 35,658
Cyclobenzaprine     7,142 13.1 5,308 - 8,976
Miscellaneous CNS agents        999 31.9 374 - 1,623
RESPIRATORY AGENTS   28,867 10.3 23,053 - 34,681
Antihistamines     4,130 20.8 2,450 - 5,809
Bronchodilators     2,920 21.1 1,713 - 4,128
Decongestants     1,511 31.0 593 - 2,428
Expectorants     2,125 29.7 887 - 3,363
Upper respiratory combinations   15,115 12.0 11,550 - 18,680
Respiratory agents NTA     4,296 18.5 2,740 - 5,852
CARDIOVASCULAR AGENTS   36,343   9.8 29,391 - 43,294
Antiadrenergic agents, centrally acting     4,810 14.4 3,455 - 6,166
Beta-adrenergic blocking agents   11,729 21.5 6,788 - 16,671
Calcium channel blocking agents     5,227 16.4 3,546 - 6,907
Diuretics     5,102 20.4 3,060 - 7,145
Cardiovascular agents NTA   17,338 10.7 13,699 - 20,977

Table 10
Nonmedical use of pharmaceuticals, by patient and visit characteristics: 2006
Patient characteristics Estimated
visits1,2
Visit characteristics Estimated
visits1,2
1 These are estimates of ED visits based on a representative sample of non-Federal, short-stay hospitals with 24-hour EDs in the United States.
2 Three dots (…) indicate that an estimate with an RSE greater than 50% or an estimate less than 30 has been suppressed.
SOURCE: Office of Applied Studies, SAMHSA, Drug Abuse Warning Network, 2006 (03/2008 update).
ED visits, nonmedical use 741,425    
Gender   Number of drugs involved  
Male 353,066 Single drug 341,796
Female 388,084 Multiple drugs 399,629
Unknown           …    
Age   Disposition  
0-5 years     6,360 Treated and released 430,260
6-11 years     4,366 Discharged home 392,512
12-17 years   65,268 Released to police/jail   17,646
18-20 years   51,972 Referred to detox/treatment   20,102
21-24 years   71,351 Admitted to this hospital 223,622
25-29 years   73,753 ICU/critical care   64,777
30-34 years   66,650 Surgery        876
35-44 years 157,450 Chemical dependency/detox           …
45-54 years 131,797 Psychiatric unit   49,413
55-64 years   50,933 Other inpatient unit 104,633
65 years and older   61,346 Other disposition   87,543
Unknown        181 Transferred   49,514
Race/ethnicity   Left against medical advice   16,097
White 508,708 Died     1,574
Black   77,553 Other           …
Hispanic   59,847 Not documented     5,459
Race/ethnicity not tabulated above (NTA)     8,433    
Unknown   86,884    

Note that ED records frequently do not distinguish methadone used for treatment of opiate addiction from the methadone in pill form that is prescribed for pain. In fact, methadone may be one of the most ambiguous drugs to categorize in DAWN. When a patient on opioid replacement therapy presents to an ED, methadone may be routinely documented in the medical record, but without sufficient information to distinguish whether the methadone was related to the ED visit.

The opioids were followed in frequency by the nonopioid analgesics containing acetaminophen (6% of nonmedical-use visits), muscle relaxants (5%), anticonvulsants (4%), and nonsteroidal anti-inflammatory agents (NSAIDs, 4%). DAWN estimates 44,314 (CI: 36,482 to 52,146) nonmedical-use visits involving nonopioid acetaminophen products. The most frequent muscle relaxant in nonmedical-use visits was carisoprodol, which was involved in 24,505 (CI: 13,352 to 35,658), or 3%, of nonmedical-use ED visits in 2006.

Among the psychotherapeutic agents, the anxiolytics (anti-anxiety agents), sedatives, and hypnotics were the most frequent, occurring in 233,875 (CI: 207,294 to 260,457) or about a third (32%) of visits associated with nonmedical use of pharmaceuticals. This category of pharmaceuticals includes barbiturates and benzodiazepines. ED visits involving benzodiazepines clearly outnumber those involving any of the other types of psychotherapeutic agents. DAWN estimates that 195,625 (CI: 167,789 to 223,461) ED visits associated with nonmedical use of pharmaceuticals involved benzodiazepines in 2006.

According to DAWN, the most frequently named benzodiazepines were alprazolam in 65,236 (CI: 50,911 to 79,561) ED visits and clonazepam in 33,557 (CI: 25,580 to 41,534) ED visits. Benzodiazepines without a specific ingredient named appeared in similar numbers: 58,348 (CI: 33,575 to 83,120) ED visits. Benzodiazepines occurring less frequently but still in substantial numbers included lorazepam in 23,720 (CI: 19,079 to 28,361) ED visits and diazepam in 19,936 (CI: 16,108 to 23,764) ED visits.

Among the other anxiolytics, sedatives, and hypnotics, the following drugs appeared in similar numbers of nonmedical-use ED visits:

For the ED visits associated with nonmedical use of pharmaceuticals, other psychotherapeutic agents of interest include antidepressants and antipsychotics. DAWN estimates:

Methylphenidate, a CNS stimulant that has captured much attention, occurs much less frequently. DAWN estimates that 2,192 (CI: 980 to 3,404) nonmedical-use ED visits involved methylphenidate.

Taking population size and the margin of error into account, visits for nonmedical use of pharmaceuticals did not differ between females (253 visits per 100,000 population) and males (237 visits per 100,000 population) (Figure 5). In terms of age, visit rates were highest for patients aged 18 to 44 and were lowest for patients aged 11 and younger.

In terms of race and ethnicity, 69% of visits related to nonmedical use of pharmaceuticals involved patients who were white (Table 10). Evaluating the relative frequencies of the race/ethnicity groups is impeded by missing data; in 12% of visits, race/ethnicity was unknown.

Patients were treated and released in about half (58%) of ED visits associated with nonmedical use of pharmaceuticals, with most discharged home (91%) and only 5% referred to detox or substance abuse treatment. In one third (30%) of all nonmedical-use visits, patients were admitted to inpatient hospital units (Table 10). Of those admitted to the hospital, about one third (29%) were sent to a critical care unit, about 22% to a psychiatric unit, and about half (47%) to other inpatient units. About 7% of ED visits for nonmedical use of pharmaceuticals resulted in transfers to another health care facility.

Figure 5
Nonmedical use of pharmaceuticals, ED visit rates by age and gender: 2006

Figure 5   D

SOURCE: Office of Applied Studies, SAMHSA, Drug Abuse Warning Network, 2006 (03/2008 update).

COMPARISONS OF ED VISITS: 2004, 2005, AND 2006

This chapter presents the comparison of the estimates of ED visits for 2006 to prior years. Differences between years are presented in terms of the percent increase or decrease in visits in 2006 compared to the estimates for 2004 or 2005. Only statistically significant changes are discussed and are shown as changes in the tables. However, with only three years' estimates to compare, caution is urged in interpreting these significant differences as trends.

Drug misuse and abuse in ED visits (Table 11)

In 2006, hospitals in the United States delivered a total of 113 million ED visits, an increase of 3.9% over 2004. The population of the United States increased 2.9%, from 294 million to 302 million, over the same period.

According to DAWN, the number of ED visits attributable to drug misuse and abuse was stable from 2004 to 2006 (Table 11).16 That is, the apparent difference is within the margin of error. Across the different types of drug involvement, changes were detected for visits involving:

Regarding the significant increases detected, it is worthwhile to consider that the number of pharmaceuticals dispensed for legitimate therapeutic uses may be increasing over time, and DAWN estimates are not adjusted to take this into account. Nor do DAWN estimates take into account the increases in the population or in ED use between 2004 and 2006.

Table 11
Drug misuse and abuse in ED visits in the U.S., by type of drug involvement: 2004, 2005, and 2006
Drug involvement1 Estimated visits2 Percent change3
2004 2005 2006 2004, 2006 2005, 2006
1 The classification of drugs used in DAWN is derived from the Multum Lexicon, © 2007, Multum Information Services, Inc. The classification was modified to meet DAWN's unique requirements (2007). The Multum Licensing Agreement governing use of the Lexicon is provided in Appendix A and can be found on the Internet at http://www.multum.com.
2 These are estimates of ED visits based on a representative sample of non-Federal, short-stay hospitals with 24-hour EDs in the United States.
3 This column denotes statistically significant (p < 0.05) increases or decreases between estimates for the periods shown.
SOURCE: Office of Applied Studies, SAMHSA, Drug Abuse Warning Network, 2006 (03/2008 update).
All types of drug misuse/abuse 1,619,054 1,616,311 1,742,887    
Illicit drugs only    502,136    517,558    536,554    
Alcohol only (age < 21)    150,988    110,599    126,704    
Pharmaceuticals only    336,987    444,309    486,276 44%  
Combinations          
Illicit drugs with alcohol    338,638    221,823    219,521    
Illicit drugs with pharmaceuticals    105,017    127,245    142,535 36%  
Alcohol with pharmaceuticals    139,716    140,275    171,743   22%
Illicit drugs with alcohol and pharmaceuticals      45,571      54,500      59,553    

Illicit drugs in ED visits (Table 12)

No changes from 2004 to 2006, nor from 2005 to 2006, were detected for ED visits involving major illicit drugs: cocaine, marijuana, heroin, and stimulants (Table 12).

Table 12
Illicit drugs in ED visits: 2004, 2005, and 2006
Drug category and selected drugs1 Estimated visits2 Percent change3
2004 2005 2006 2004, 2006 2005, 2006
1 The classification of drugs used in DAWN is derived from the Multum Lexicon, © 2007, Multum Information Services, Inc. The classification was modified to meet DAWN's unique requirements (2007). The Multum Licensing Agreement governing use of the Lexicon is provided in Appendix A and can be found on the Internet at http://www.multum.com.
2 These are estimates of ED visits based on a representative sample of non-Federal, short-stay hospitals with 24-hour EDs in the United States.
3 This column denotes statistically significant (p < 0.05) increases or decreases between estimates for the periods shown.
SOURCE: Office of Applied Studies, SAMHSA, Drug Abuse Warning Network, 2006 (03/2008 update).
Total drug misuse/abuse ED visits 1,619,054 1,616,311 1,742,887    
ED visits, illicit drugs   991,363   921,127   958,164    
Cocaine   475,425   483,865   548,608    
Heroin   214,432   187,493   189,780    
Marijuana    281,619    279,664    290,563    
Stimulants    162,435    137,650    107,575    
Amphetamines      34,085      34,928      32,240    
Methamphetamine    132,576    109,655      79,924    
MDMA (Ecstasy)      10,220      11,287      16,749   64%   48%
GHB        1,789        1,036        1,084    
Flunitrazepam (Rohypnol)             …             …             …    
Ketamine             …          303          270    
LSD        2,146        2,001        4,002   100%
PCP      31,342      14,825      21,960    
Miscellaneous hallucinogens        3,150        3,194        3,898    
Inhalants        9,523        5,156        5,643 -41%  
Combinations not tabulated above (NTA)             …        3,201        2,055    

Alcohol in ED visits (Tables 13-14)

No significant changes in alcohol-related ED visits occurred during the period from 2004 to 2006, nor for the period 2005 to 2006 (Tables 13-14). These findings were consistent for all the alcohol-related ED visits: alcohol overall, alcohol in combination with other drugs, and alcohol alone in underage patients.

Table 13
Alcohol in drug-related ED visits: 2004, 2005, and 2006
Drug category and selected drugs1 Estimated visits2 Percent change3
2004 2005 2006 2004, 2006 2005, 2006
1 The classification of drugs used in DAWN is derived from the Multum Lexicon, © 2007, Multum Information Services, Inc. The classification was modified to meet DAWN's unique requirements (2007). The Multum Licensing Agreement governing use of the Lexicon is provided in Appendix A and can be found on the Internet at http://www.multum.com.
2 These are estimates of ED visits based on a representative sample of non-Federal, short-stay hospitals with 24-hour EDs in the United States.
3 This column denotes statistically significant (p < 0.05) increases or decreases between estimates for the periods shown.
SOURCE: Office of Applied Studies, SAMHSA, Drug Abuse Warning Network, 2006 (03/2008 update).
Total drug misuse/abuse ED visits 1,619,054 1,616,311 1,742,887    
ED visits, alcohol    674,914    527,198    577,521    
Alcohol in combination    523,926    416,599    450,817    
Alcohol alone    150,988    110,599    126,704    

Table 14
Alcohol in drug-related ED visits in patients under age 21: 2004, 2005, and 2006
Drug category and selected drugs1 Estimated visits2 Percent change3
2004 2005 2006 2004, 2006 2005, 2006
1 The classification of drugs used in DAWN is derived from the Multum Lexicon, © 2007, Multum Information Services, Inc. The classification was modified to meet DAWN's unique requirements (2007). The Multum Licensing Agreement governing use of the Lexicon is provided in Appendix A and can be found on the Internet at http://www.multum.com.
2 These are estimates of ED visits based on a representative sample of non-Federal, short-stay hospitals with 24-hour EDs in the United States.
3 This column denotes statistically significant (p < 0.05) increases or decreases between estimates for the periods shown.
SOURCE: Office of Applied Studies, SAMHSA, Drug Abuse Warning Network, 2006 (03/2008 update).
Patients aged 12-17
ED visits, alcohol   67,589 62,459   76,760    
Alcohol in combination   21,555 19,720   24,418    
Alcohol alone   46,034 42,739   52,342    
Patients aged 18-20
ED visits, alcohol 135,313 95,166 105,675    
Alcohol in combination   31,926 27,784   31,702    
Alcohol alone 103,387 67,382   73,973    

Nonmedical use of pharmaceuticals (Table 15)

ED visits related to nonmedical use of pharmaceuticals increased 38% in the period from 2004 to 2006 (Table 15). Among the drugs most frequently implicated in nonmedical use, the following changes from 2004 to 2006 are notable:

For the period 2005 to 2006, no change was detected in the overall number of ED visits related to nonmedical use of pharmaceuticals nor were changes noted for the substances most frequently implicated in nonmedical-use visits.

Table 15
Nonmedical use of pharmaceuticals ED visits: 2004, 2005, and 2006
Drug category and selected drugs1 Estimated visits2,3 Percent change4
2004 2005 2006 2004, 2006 2005, 2006
1 The classification of drugs used in DAWN is derived from the Multum Lexicon, © 2007, Multum Information Services, Inc. The classification was modified to meet DAWN's unique requirements (2007). The Multum Licensing Agreement governing use of the Lexicon is provided in Appendix A and can be found on the Internet at http://www.multum.com.
2 These are estimates of ED visits based on a representative sample of non-Federal, short-stay hospitals with 24-hour EDs in the United States.
3 Three dots (…) indicate that an estimate with an RSE greater than 50% or an estimate less than 30 has been suppressed.
4 This column denotes statistically significant (p < 0.05) increases or decreases between estimates for the periods shown.
SOURCE: Office of Applied Studies, SAMHSA, Drug Abuse Warning Network, 2006 (03/2008 update).
ED visits, nonmedical use 536,247 669,214 741,425   38%  
PSYCHOTHERAPEUTIC AGENTS 247,324 308,655 323,999   31%  
Antidepressants   66,917   67,051   79,682    
MAO inhibitors           …           …           …    
SSRI antidepressants   32,285   30,374   35,370    
Tricyclic antidepressants   12,412   14,515   16,564    
Miscellaneous antidepressants     9,414     7,452     7,561    
Antipsychotics   35,198   44,393   44,733    
Anxiolytics, sedatives, and hypnotics 177,394 227,486 233,875   32%  
Barbiturates   11,721   14,693   10,991    
Benzodiazepines 143,546 189,704 195,625   36%  
Alprazolam   46,526   57,419   65,236   40%  
Clonazepam   28,178   30,648   33,557    
Diazepam   15,619   18,433   19,936    
Lorazepam   17,674   23,210   23,720    
Benzodiazepines NOS   36,039   61,486   58,347    
Misc. anxiolytics, sedatives, and hypnotics   31,554   35,561   40,626   29%  
Diphenhydramine   10,452   10,294   12,291    
Hydroxyzine     2,363     2,179     2,678    
Zolpidem   12,792   14,730   17,257    
Anxiolytics, sedatives, and hypnotics NOS     2,657     4,421     3,629    
CNS stimulants     9,801   10,965   13,892   42%  
Amphetamine-dextroamphetamine     2,303     2,669     5,027 118%  
Caffeine     2,736     4,567     4,407    
Dextroamphetamine           …           …           …    
Methylphenidate     2,446     2,519     2,192    
CENTRAL NERVOUS SYSTEM AGENTS 282,296 336,900 373,138   32%  
Analgesics 241,578 294,251 323,579   34%  
Antimigraine agents        868     1,018     1,191    
Cox-2 inhibitors     1,935        765           …    
Opiates/opioids 172,726 217,594 247,669   43%  
Opiates/opioids, unspecified   31,846   52,670   50,978   60%  
Narcotic analgesics 144,644 168,376 201,280   39% 20%
Buprenorphine/combinations           …           …     4,440    
Codeine/combinations     7,171     6,180     6,928    
Fentanyl/combinations     9,823   11,211   16,012    
Hydrocodone/combinations   39,844   47,192   57,550   44%  
Hydromorphone/combinations     3,385     4,714     6,780    
Meperidine/combinations        782        383     1,440    
Methadone   36,806   42,684   45,130    
Morphine/combinations   13,966   15,762   20,416   46%  
Oxycodone/combinations   41,701   52,943   64,888   56%  
Propoxyphene/combinations     6,744     7,648     6,220    
Nonsteroidal anti-inflammatory agents   27,362   28,837   27,662    
Ibuprofen   22,127   22,268   20,541    
Naproxen     4,715     5,190     6,651    
Salicylates/combinations     9,580   12,123   10,399    
Miscellaneous analgesics/combinations   44,857   51,881   54,313    
Acetaminophen/combinations   39,167   43,558   44,314    
Tramadol/combinations     4,849     5,918     6,048    
Tramadol     3,948     5,427     5,961    
Acetaminophen-tramadol        909           …           …    
Analgesic combinations not tabulated above (NTA)        977        653        898    
Anorexiants           …     1,757     1,168    
Anticonvulsants   28,652   27,641   31,169    
Antiemetic/antivertigo agents     1,678     1,771     1,360    
Anti-Parkinson agents     2,472     1,692     3,816    
General anesthetics           …           …           …    
Muscle relaxants   25,934   33,695   38,918   50%  
Carisoprodol   14,736   20,082   24,505    
Cyclobenzaprine     6,183     7,629     7,142    
Miscellaneous CNS agents        869        900        999    
RESPIRATORY AGENTS   22,286   28,017   28,867    
Antihistamines     5,761     4,429     4,130    
Bronchodilators     2,294     3,043     2,920    
Decongestants     1,864     1,310     1,511    
Expectorants        832     1,960     2,125 155%  
Upper respiratory combinations   10,314   15,837   15,115    
Respiratory agents NTA     2,903     3,692     4,296    
CARDIOVASCULAR AGENTS   27,396   37,095   36,343    
Antiadrenergic agents, centrally acting     3,616     5,125     4,810    
Beta-adrenergic blocking agents     7,094     9,824   11,729    
Calcium channel blocking agents     3,115     5,434     5,227    
Diuretics     3,625     5,332     5,102    
Cardiovascular agents NTA   14,930   18,881   17,338    

SPECIAL TYPES OF DRUG-RELATED ED VISITS

This chapter profiles two special types of drug-related ED visits captured by DAWN: drug-related suicide attempts and seeking detox cases. These are analyzed by DAWN as separate and distinct classes of drug misuse or abuse.

Suicide attempts (Tables 16-17, Figure 6)

DAWN estimates 182,805 (CI: 154,185 to 211,424) ED visits for drug-related suicide attempts in 2006 (Table 16). Although DAWN includes only suicide attempts that involve drugs, these attempts are not limited to drug overdoses. If there is drug involvement in a suicide attempt by other means (e.g., by gun), the case is included as drug related. However, suicide attempts not involving drugs at all (e.g., by gun alone) are excluded. Also excluded are suicide-related behaviors documented as something other than actual attempts (e.g., suicidal ideation, suicidal gesture, or suicidal thoughts).

Nearly two thirds (65%) of ED visits for drug-related suicide attempts involved multiple drugs (Table 17). Alcohol, either in combination with other drugs or alcohol alone in patients under age 21, was the most frequently implicated drug and was involved in one third (30%) of the ED visits for drug-related suicide attempts. Since DAWN excludes visits for adults when alcohol is the only drug, the role of alcohol in suicide attempts is probably larger. Illicit drugs were involved in just under one quarter (23%) of the ED visits for drug-related suicide attempts. The most frequently reported illicit drugs were cocaine (15% of visits) and marijuana (8% of visits), but the margins of error for the illicit drugs are quite large and the numbers are relatively small when compared with the pharmaceuticals.

Pharmaceuticals were involved in the majority (92%) of ED visits for drug-related suicide attempts, and it is not possible, based on ED medical record documentation, to measure the extent to which these pharmaceuticals may have been prescribed to the patient for a preexisting condition. More than half (58%) of ED visits for drug-related suicide attempts involved psychotherapeutic agents, and 45% involved central nervous system (CNS) agents. The most commonly used psychotherapeutic agents were benzodiazepines (48% of suicide-attempt visits involving psychotherapeutics) and antidepressants (35%). The CNS agents were primarily analgesics (pain relievers) and included both prescription and over-the-counter (OTC) formulations. DAWN estimates that the most commonly used pain relievers were opiates/opioids and acetaminophen/combinations, which were each present in approximately a third (33% and 31%, respectively) of suicide-attempt visits involving CNS agents, followed by nonsteroidal anti-inflammatory agents (NSAIDs, such as ibuprofen and naproxen, 19%) and salicylates/combinations (aspirins, 7%).

About half (55%) of the suicide attempts were admitted for inpatient hospital care. A fifth (21%) were admitted to an ICU/critical care unit; others were admitted to psychiatric units (18%) or other inpatient units (16%). Another 25% were transferred to another health care facility; only 14% were discharged home. Very few died in the ED. However, DAWN does not record deaths for patients who died before arriving at the ED or patients who died after admission to inpatient units of the hospital.

Table 16
Suicide attempts: 2006
Drug category and selected drugs1 Estimated visits2,3,4 Relative standard error (RSE) 95% Confidence interval
Lower bound - Upper bound
1 The classification of drugs used in DAWN is derived from the Multum Lexicon, © 2007, Multum Information Services, Inc. The classification was modified to meet DAWN's unique requirements (2007). The Multum Licensing Agreement governing use of the Lexicon is provided in Appendix A and can be found on the Internet at http://www.multum.com.
2 These are estimates of ED visits based on a representative sample of non-Federal, short-stay hospitals with 24-hour EDs in the United States.
3 Three dots (…) indicate that an estimate with an RSE greater than 50% or an estimate less than 30 has been suppressed.
4 This column denotes statistically significant (p < 0.05) increases or decreases between estimates for the periods shown.
SOURCE: Office of Applied Studies, SAMHSA, Drug Abuse Warning Network, 2006 (03/2008 update).
Total drug-related ED visits, suicide attempts 182,805   8.0 154,185 - 211,424
Major substances of abuse
Alcohol   54,820   5.4 48,993 - 60,647
Alcohol in combination   54,337   5.4 48,587 - 60,087
Alcohol alone        483 44.4 63 - 903
Non-alcohol illicits   42,148 23.3 22,914 - 61,382
Cocaine   26,510 26.6 12,705 - 40,316
Heroin     4,265 28.3 1,903 - 6,627
Marijuana   15,272 26.4 7,371 - 23,174
Stimulants     4,829 18.8 3,048 - 6,610
Amphetamines     2,228 25.8 1,104 - 3,353
Methamphetamine     2,877 27.5 1,327 - 4,427
MDMA (Ecstasy)     1,239 46.9 101 - 2,377
GHB           …     … -
Flunitrazepam (Rohypnol)           …     … -
Ketamine           …     … -
LSD           …     … -
PCP           … 71.8 -
Miscellaneous hallucinogens           …     … -
Inhalants           …     … -
Combinations not tabulated above (NTA)           …     … -
Other substances
PSYCHOTHERAPEUTIC AGENTS 106,128   7.6 90,385 - 121,871
Antidepressants   36,677 12.7 27,570 - 45,784
MAO inhibitors           …     … -
SSRI antidepressants   16,973 10.9 13,357 - 20,589
Tricyclic antidepressants     4,681 28.1 2,107 - 7,255
Miscellaneous antidepressants     3,806 28.8 1,660 - 5,953
Antipsychotics   22,491 13.4 16,566 - 28,416
Anxiolytics, sedatives, and hypnotics   68,177   7.1 58,632 - 77,723
Barbiturates     2,031 41.8 367 - 3,696
Benzodiazepines   50,431   7.5 43,030 - 57,832
Alprazolam   15,633 14.2 11,291 - 19,974
Clonazepam   14,173 12.4 10,726 - 17,620
Diazepam     5,910 24.4 3,086 - 8,733
Lorazepam     6,682 13.6 4,904 - 8,460
Benzodiazepines NOS     7,080 35.9 2,092 - 12,069
Misc. anxiolytics, sedatives, and hypnotics   21,527 9.7 17,443 - 25,611
Diphenhydramine     7,756 14.6 5,543 - 9,970
Hydroxyzine     1,957 23.6 1,053 - 2,860
Zolpidem     6,674 13.6 4,890 - 8,458
Anxiolytics, sedatives, and hypnotics NOS     1,406 25.7 698 - 2,115
CNS stimulants     1,949 33.1 683 - 3,214
Amphetamine-dextroamphetamine        559 47.5 38 - 1,079
Caffeine           …     … -
Dextroamphetamine           …     … -
Methylphenidate        633 39.6 141 - 1,124
CENTRAL NERVOUS SYSTEM AGENTS   82,442   7.3 70,683 - 94,201
Analgesics   67,623   7.4 57,880 - 77,366
Antimigraine agents           …     … -
Cox-2 inhibitors           …     … -
Opiates/opioids   27,185   9.9 21,928 - 32,442
Opiates/opioids, unspecified     3,129 23.5 1,686 - 4,573
Narcotic analgesics   24,470 10.0 19,695 - 29,244
Buprenorphine/combinations           …     … -
Codeine/combinations     2,349 22.7 1,306 - 3,392
Fentanyl/combinations           …     … -
Hydrocodone/combinations     8,998 11.4 6,981 - 11,016
Hydromorphone/combinations        262 49.5 8 - 516
Meperidine/combinations           …     … -
Methadone     1,772 29.3 755 - 2,788
Morphine/combinations           … 50.5 -
Oxycodone/combinations     7,842 18.9 4,934 - 10,750
Propoxyphene/combinations     2,811 26.9 1,331 - 4,292
Nonsteroidal anti-inflammatory agents   15,956 15.0 11,280 - 20,632
Ibuprofen   12,064 15.0 8,523 - 15,605
Naproxen     3,726 20.9 2,201 - 5,252
Salicylates/combinations     5,400 10.4 4,294 - 6,506
Miscellaneous analgesics/combinations   27,371   9.3 22,367 - 32,376
Acetaminophen/combinations   25,312   9.2 20,757 - 29,867
Tramadol/combinations     1,719 23.6 925 - 2,512
Tramadol     1,372 26.6 656 - 2,088
Acetaminophen-tramadol           …     … -
Analgesic combinations NTA        920 44.7 114 - 1,726
Anorexiants        654 31.5 251 - 1,058
Anticonvulsants   12,580 12.3 9,548 - 15,612
Antiemetic/antivertigo agents           …     … -
Anti-Parkinson agents           … 51.9 -
General anesthetics           …     … -
Muscle relaxants     7,072 14.4 5,071 - 9,074
Carisoprodol     3,811 23.3 2,068 - 5,554
Cyclobenzaprine     2,096 23.3 1,140 - 3,052
Miscellaneous CNS agents           …     … -
RESPIRATORY AGENTS     8,415 13.5 6,182 - 10,647
Antihistamines     1,627 22.0 925 - 2,329
Bronchodilators           …     … -
Decongestants     1,347 32.9 479 - 2,215
Expectorants     1,068 33.8 361 - 1,775
Upper respiratory combinations     3,982 16.8 2,670 - 5,294
Respiratory agents NTA        660 32.8 235 - 1,084
CARDIOVASCULAR AGENTS     7,965 16.5 5,389 - 10,542
Antiadrenergic agents, centrally acting     1,930 26.8 917 - 2,942
Beta-adrenergic blocking agents     1,999 20.3 1,202 - 2,795
Calcium channel blocking agents     1,040 28.2 466 - 1,614
Diuretics           … 51.0 -
Cardiovascular agents NTA     3,298 23.2 1,799 - 4,798

Table 17
Suicide attempts, by patient and visit characteristics: 2006
Patient characteristics Estimated visits1,2 Visit characteristics Estimated visits1,2
1 These are estimates of ED visits based on a representative sample of non-Federal, short-stay hospitals with 24-hour EDs in the United States.
2 Three dots (…) indicate that an estimate with an RSE greater than 50% or an estimate less than 30 has been suppressed.
SOURCE: Office of Applied Studies, SAMHSA, Drug Abuse Warning Network, 2006 (03/2008 update).
Total drug-related ED visits, suicide attempts 182,805    
Gender   Number of drugs involved  
Male   71,657 Single drug   64,143
Female 111,137 Multiple drugs 118,661
Unknown           …    
Age   Disposition  
0-5 years           … Treated and released   31,528
6-11 years           … Discharged home   25,149
12-17 years   20,506 Released to police/jail     2,080
18-20 years   14,232 Referred to detox/treatment     4,299
21-24 years   18,855 Admitted to this hospital 101,409
25-29 years   21,877 ICU/critical care   37,821
30-34 years   17,095 Surgery           …
35-44 years   44,237 Chemical dependency/detox           …
45-54 years   32,970 Psychiatric unit   32,682
55-64 years     8,462 Other inpatient unit   30,129
65 years and older     4,352 Other disposition   49,867
Unknown           … Transferred   45,234
Race/ethnicity   Left against medical advice        458
White 114,972 Died           …
Black   28,491 Other           …
Hispanic   18,058 Not documented     1,747
Race/ethnicity not tabulated above (NTA)     2,095    
Unknown   19,188    

After accounting for population size and the margin of error, the rate of drug-related suicide visits for females (73 visits per 100,000 population) was higher than that for males (48 per 100,000) (Figure 6). In general, the rates for patients aged 18 to 54 exceeded the rates for younger and older age groups. The rate for patients aged 12 to 17 (81 visits per 100,000) exceeded the rates for patients aged 55 and over.

Figure 6
Suicide attempts, ED visit rates by age and gender: 2006

Figure 6   D

SOURCE: Office of Applied Studies, SAMHSA, Drug Abuse Warning Network, 2006 (03/2008 update).

In terms of race/ethnicity, 63% of the suicide attempts involved patients who were white. Evaluating the relative frequencies of the race/ethnicity groups is impeded by missing data; in 10% of visits, race/ethnicity was unknown.

Suicide attempt ED visits: 2004, 2005, and 2006 (Table 18)

Overall, there was no significant change in ED visits for drug-related suicide attempts from 2004 to 2006, but an increase was detected from 2005 to 2006 (Table 18). Increases were evident from 2004 to 2006 for some of the drugs frequently involved in suicide attempts, such as benzodiazepines, which increased 36%, and opiate/opioid analgesics, which increased 44%.

Table 18
Suicide attempts: 2004, 2005, and 2006
Drug category and selected drugs1 Estimated visits2,3 Percent change4
2004 2005 2006 2004, 2006 2005, 2006
1 The classification of drugs used in DAWN is derived from the Multum Lexicon, © 2007, Multum Information Services, Inc. The classification was modified to meet DAWN's unique requirements (2007). The Multum Licensing Agreement governing use of the Lexicon is provided in Appendix A and can be found on the Internet at http://www.multum.com.
2 These are estimates of ED visits based on a representative sample of non-Federal, short-stay hospitals with 24-hour EDs in the United States.
3 Three dots (…) indicate that an estimate with an RSE greater than 50% or an estimate less than 30 has been suppressed.
4 This column denotes statistically significant (p < 0.05) increases or decreases between estimates for the periods shown.
SOURCE: Office of Applied Studies, SAMHSA, Drug Abuse Warning Network, 2006 (03/2008 update).
Total drug-related ED visits, suicide attempts 161,586 151,568 182,805   21%
Major substances of abuse
Alcohol   48,726   47,891   54,820    
Alcohol in combination   48,080   46,806   54,337    
Alcohol alone        646     1,085        483    
Cocaine   19,520   19,628   26,510    
Heroin     4,579     3,167     4,265   35%
Marijuana   12,074   11,955   15,272    
Stimulants     4,535     5,410     4,829    
Amphetamines     1,560     1,646     2,228    
Methamphetamine     3,136     3,853     2,877    
MDMA (Ecstasy)           …        529     1,239    
GHB           …           …           …    
Flunitrazepam (Rohypnol)           …           …           …    
Ketamine           …           …           …    
LSD           …           …           …    
PCP           …           …           …    
Miscellaneous hallucinogens           …           …           …    
Inhalants           …        794           …    
Combinations not tabulated above (NTA)           …           …           …    
Other substances
PSYCHOTHERAPEUTIC AGENTS   88,034   82,144 106,128   29%
Antidepressants   33,366   27,086   36,677    
MAO inhibitors           …           …           …    
SSRI antidepressants   18,513   13,377   16,973    
Tricyclic antidepressants     3,555     3,008     4,681    
Miscellaneous antidepressants     3,337     2,681     3,806    
Antipsychotics   17,807   17,129   22,491    
Anxiolytics, sedatives, and hypnotics   52,653   52,022   68,177 29% 31%
Barbiturates     1,949     1,219     2,031    
Benzodiazepines   36,995   35,676   50,431 36% 41%
Alprazolam   11,354   14,530   15,633    
Clonazepam     9,403     9,064   14,173   56%
Diazepam     4,630     3,968        599    
Lorazepam     6,065     5,182     6,682    
Benzodiazepines NOS     4,426     3,343     7,080    
Misc. anxiolytics, sedatives, and hypnotics   16,790   17,522   21,527    
Diphenhydramine     7,458     6,583     7,756    
Hydroxyzine     2,346     1,795     1,956    
Zolpidem     4,355     4,972     6,674    
Anxiolytics, sedatives, and hypnotics NOS     1,859     2,147     1,406    
CNS stimulants     1,654     1,782     1,949    
Amphetamine-dextroamphetamine           …           …        559    
Caffeine           …        450           …    
Dextroamphetamine           …           …           …    
Methylphenidate           …        818        633    
CENTRAL NERVOUS SYSTEM AGENTS   73,949   66,321   82,442   24%
Analgesics   61,095   54,858   67,623   23%
Antimigraine agents           …           …           …    
Cox-2 inhibitors        807        514           …    
Opiates/opioids   18,939   20,359   27,185 44% 34%
Opiates/opioids, unspecified     2,363     2,819     3,129    
Narcotic analgesics   16,928   17,801   24,470 45% 37%
Buprenorphine/combinations           …           …           …    
Codeine/combinations     1,750     2,656     2,349    
Fentanyl/combinations           …           …           …    
Hydrocodone/combinations     7,034     7,035     8,998    
Hydromorphone/combinations           …           …        262    
Meperidine/combinations           …           …           …    
Methadone     1,287     1,596     1,772    
Morphine/combinations        714     1,210           …    
Oxycodone/combinations     5,340     4,229     7,842   85%
Propoxyphene/combinations     1,888     2,129     2,811    
Nonsteroidal anti-inflammatory agents   19,114   14,117   15,956    
Ibuprofen   13,609   10,917   12,064    
Naproxen     4,383     3,224     3,726    
Salicylates/combinations     6,211     4,645     5,400    
Miscellaneous analgesics/combinations   22,864   22,692   27,371    
Acetaminophen/combinations   20,701   21,017   25,312    
Tramadol/combinations     1,742     1,515     1,719    
Tramadol     1,528     1,079     1,372    
Acetaminophen-tramadol           …           …           …    
Analgesic combinations NTA           …           …        920    
Anorexiants           …           …        654    
Anticonvulsants   10,957     9,389   12,580    
Antiemetic/antivertigo agents           …           …           …    
Anti-Parkinson agents         80        543           …    
General anesthetics           …           …           …    
Muscle relaxants     5,921     5,785     7,072    
Carisoprodol     1,864     2,038     3,811    
Cyclobenzaprine     2,966     2,784     2,096    
Miscellaneous CNS agents           …           …           …    
RESPIRATORY AGENTS     8,361     7,662     8,415    
Antihistamines     2,059     1,650     1,627    
Bronchodilators           …           …           …    
Decongestants           …           …     1,347    
Expectorants           …        474     1,068    
Upper respiratory combinations     4,818     4,207     3,982    
Respiratory agents NTA           …     1,244        660    
CARDIOVASCULAR AGENTS     7,667     5,814     7,965    
Antiadrenergic agents, centrally acting        995        912     1,929    
Beta-adrenergic blocking agents     2,105     1,916     1,999    
Calcium channel blocking agents        879        193     1,040   438%
Diuretics           …        539           …    
Cardiovascular agents NTA     3,661     3,024     3,298    

Seeking detox (Tables 19-20, Figure 7)

DAWN estimates 118,355 (CI: 90,171 to 146,540) drug-related ED visits for patients seeking detoxification or substance abuse treatment services during 2006. These "seeking detox" visits tend to be concentrated in hospitals with administrative practices that require medical clearance in the ED for admission to detox or substance abuse treatment units within the hospital. Therefore, this estimate does not encompass the full extent of the demand for these services.

Nearly two thirds (65%) of the seeking detox ED visits involved multiple drugs, and more than one third (40%) of all seeking detox ED visits involved alcohol (Table 19). However, the role of alcohol may be underrepresented here, because for adults aged 21 and older this includes only alcohol in combination with other drugs. Among the illicit drugs, cocaine (49% of visits) and heroin (29% of visits) occurred most frequently, followed by marijuana (19% of visits) and amphetamine or methamphetamine stimulants (7% of visits). Among the pharmaceuticals, psychotherapeutic agents, which were primarily benzodiazepines (13%), and CNS agents, which were primarily opiate/opioid analgesics (26%), were notable. Among the opiates/opioids, hydrocodone/combinations and oxycodone/combinations were most frequent.

Among the seeking detox ED visits, nearly 7 out of 10 (69%) received some type of follow-up care, either inpatient admission, referral elsewhere for detox or substance abuse treatment services, or transfer to another health care facility (Table 20). However, about one quarter (27%) of seeking detox cases may not have received the care they sought because they were discharged to home.

Taking population size and the margin of error into account, the rates of seeking detox visits were similar across all age groups in the 18 to 44 range. The rate of seeking detox visits for males (51 per 100,000 population) was higher than that for females (27 per 100,000 population).

In terms of race/ethnicity, the majority (59%) of seeking detox visits involved patients who were white. Evaluating the relative frequencies of the race/ethnicity groups is impeded by missing data; in 9% of visits race/ethnicity was unknown.

Table 19
Seeking detox: 2006
Drug category and selected drugs1 Estimated visits2,3,4 Relative standard error (RSE) 95% Confidence interval
Lower
bound
- Upper
bound
1 The classification of drugs used in DAWN is derived from the Multum Lexicon, © 2007, Multum Information Services, Inc. The classification was modified to meet DAWN's unique requirements (2007). The Multum Licensing Agreement governing use of the Lexicon is provided in Appendix A and can be found on the Internet at http://www.multum.com.
2 These are estimates of ED visits based on a representative sample of non-Federal, short-stay hospitals with 24-hour EDs in the United States.
3 Estimates are all expressed in visits. Visits cannot be summed across drugs because drug-related visits often involve multiple drugs.
4 Three dots (…) indicate that an estimate with an RSE greater than 50% or an estimate less than 30 has been suppressed.
SOURCE: Office of Applied Studies, SAMHSA, Drug Abuse Warning Network, 2006 (03/2008 update).
Total drug-related ED visits, seeking detox 118,355 12.1 90,171 - 146,540
Major substance of abuse
Alcohol   47,102 14.3 33,887 - 60,316
Alcohol in combination   46,769 14.3 33,646 - 59,892
Alcohol alone           … 57.5 -
Non-alcohol illicits   92,385 12.6 69,548 - 115,223
Cocaine   57,738 14.1 41,815 - 73,661
Heroin   34,462 14.6 24,611 - 44,312
Marijuana   22,104 16.4 14,983 - 29,226
Stimulants     8,128 26.2 3,955 - 12,301
Amphetamines     2,034 26.1 993 - 3,074
Methamphetamine     6,211 31.2 2,407 - 10,014
MDMA (Ecstasy)        483 35.7 145 - 821
GHB           …     … -
Flunitrazepam (Rohypnol)           …     … -
Ketamine           …     … -
LSD           … 54.3 -
PCP        989 41.5 184 - 1,794
Miscellaneous hallucinogens           …     … -
Inhalants           …     … -
Combinations not tabulated above (NTA)           … 50.3 -

Table 20
Seeking detox, by patient and visit characteristics: 2006
Patient characteristics Estimated visits1,2 Visit characteristics Estimated visits1,2
1 These are estimates of ED visits based on a representative sample of non-Federal, short-stay hospitals with 24-hour EDs in the United States.
2 Three dots (…) indicate that an estimate with an RSE greater than 50% or an estimate less than 30 has been suppressed.
SOURCE: Office of Applied Studies, SAMHSA, Drug Abuse Warning Network, 2006 (03/2008 update).
Total drug-related ED visits, seeking detox 118,355    
Gender   Number of drugs involved  
Male   76,659 Single drug   40,924
Female   41,528 Multiple drugs   77,432
Unknown           …    
Age   Disposition  
0-5 years           … Treated and released   69,063
6-11 years           … Discharged home   32,430
12-17 years     3,759 Released to police/jail        791
18-20 years     8,757 Referred to detox/treatment   35,842
21-24 years   11,135 Admitted to this hospital   35,278
25-29 years   17,804 ICU/critical care        897
30-34 years   12,799 Surgery           …
35-44 years   36,665 Chemical dependency/detox   22,540
45-54 years   22,222 Psychiatric unit     6,902
55-64 years     4,521 Other inpatient unit     4,869
65 years and older        681 Other disposition   14,015
Unknown           … Transferred   10,049
Race/ethnicity   Left against medical advice     1,947
White   69,867 Died           …
Black   25,448 Other     1,447
Hispanic   11,397 Not documented       573
Race/ethnicity not tabulated above (NTA)        737    
Unknown   10,907    

Figure 7
Seeking detox, ED visit rates by age and gender: 2006

Figure 7   D

SOURCE: Office of Applied Studies, SAMHSA, Drug Abuse Warning Network, 2006 (03/2008 update).

Seeking detox ED visits: 2004, 2005, and 2006 (Table 21)

No significant changes in ED visits from 2004 to 2006, or from 2005 to 2006, were detected for seeking detox ED visits overall, or for alcohol or the illicit drugs involved in these visits (Table 21).

Table 21
Seeking detox: 2004, 2005, and 2006
Drug category and selected drugs1 Estimated visits2,3 Percent change4
2004 2005 2006 2004, 2006 2005, 2006
1 The classification of drugs used in DAWN is derived from the Multum Lexicon, © 2007, Multum Information Services, Inc. The classification was modified to meet DAWN's unique requirements (2007). The Multum Licensing Agreement governing use of the Lexicon is provided in Appendix A and can be found on the Internet at http://www.multum.com.
2 These are estimates of ED visits based on a representative sample of non-Federal, short-stay hospitals with 24-hour EDs in the United States.
3 Three dots (…) indicate that an estimate with an RSE greater than 50% or an estimate less than 30 has been suppressed.
4 This column denotes statistically significant (p < 0.05) increases or decreases between estimates for the periods shown.
SOURCE: Office of Applied Studies, SAMHSA, Drug Abuse Warning Network, 2006 (03/2008 update).
Total drug-related ED visits, seeking detox 141,867 126,226 118,355    
Major substances of abuse
Alcohol   53,662   47,494   47,102    
Alcohol in combination   51,831   47,154   46,769    
Alcohol alone           …           …           …    
Cocaine   62,989   56,061   57,738    
Heroin   47,035   40,895   34,462    
Marijuana   25,965   22,486   22,104    
Stimulants   11,760   15,402     8,128    
Amphetamines           …           …     2,034    
Methamphetamine           …           …     6,211    
MDMA (Ecstasy)        882        511        483    
GHB           …           …           …    
Flunitrazepam (Rohypnol)           …           …           …    
Ketamine           …           …           …    
LSD           …           …           …    
PCP        827        729        989    
Miscellaneous hallucinogens           …           …           …    
Inhalants           …           …           …    
Combinations not tabulated above (NTA)           …        191           …    


APPENDIX A

MULTUM LEXICON
END-USER LICENSE AGREEMENT

1. Introduction

  1. This License Agreement (the "License") applies to the Multum Lexicon database (the "Database"). This License does not apply to any other products or services of Cerner Multum, Inc. ("Multum"). A "work based on the Database" means either the Database or any derivative work under copyright law; i.e., a work containing the Database or a substantial portion of it, either verbatim or with modifications. A translation of the Database is included without limitation in the term "modification". Each end-user/licensee is addressed herein as "you".

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APPENDIX B

GLOSSARY OF TERMS

This glossary defines terms used in data collection activities, analyses, and publications associated with the emergency department (ED) component of the Drug Abuse Warning Network (DAWN).

Accidental ingestion: This category of drug-related ED visits includes those involving the accidental use of a drug, for example, childhood drug poisonings and individuals who take the wrong medication by mistake.

Adverse reaction: This category of drug-related ED visits represents the consequences of using a prescription or over-the-counter (OTC) pharmaceutical for therapeutic purposes and includes visits related to adverse drug reactions, side effects, drug-drug interactions, and drug-alcohol interactions. Adverse reactions that involve a pharmaceutical with an illicit drug are exceptions that are excluded from this category.

Alcohol only (age less than 21): This category of drug-related ED visits includes those in which alcohol was the only drug involved and the patient was aged less than 21. Although alcohol is an illegal drug for minors, combining these cases with other cases involving illicit drugs tends to mask rather than highlight their importance for prevention and treatment efforts. Most instances of alcohol as the only drug in patients under age 21 are classified in the alcohol only (age < 21) case type. However, some are classified as suicide-attempt or seeking detox, case types that precede alcohol only (age < 21) in sequence.

Case description: A description of how the drug(s) was related to the patient's ED visit. The case description, in conjunction with other documentation in the ED medical record, is used to determine if the ED visit is reportable to DAWN. It is copied verbatim from the patient's chart when possible.

Case type: See Type of case.

Case type other: See Drug misuse and abuse.

Confidence interval (CI): An interval estimate, that is, a range of values around a point estimate that takes sampling error into account. Ninety-five percent is an accepted standard of confidence. Technically, a 95% CI means that, if repeated samples were drawn from the same population of hospitals using the same sampling and data collection procedures, the true population value would fall within the confidence interval 95% of the time. Practically, a 95% CI summarizes both the estimate and its margin of error in a straightforward way with a reasonable degree of confidence. Calculation of 95% CIs is discussed in Appendix C.

Diagnosis: The condition(s) for which the patient was treated as determined by the clinician after study.

Disposition: The location or facility to which an ED patient was referred, transferred, or released.

Treated and released includes three categories:

Admitted to this hospital includes five categories of inpatient units:

Other disposition includes five categories:

Drug: A substance that was recorded in a DAWN case report. Substances accepted by DAWN include alcohol, illicit drugs, prescription and over-the-counter pharmaceuticals, dietary supplements, and nonpharmaceutical inhalants. Multiple substances ("drugs") can be reported for each DAWN case. Therefore, the total number of drugs exceeds the total number of DAWN cases reported. (See also single-drug case.)

Drug category: A generic grouping of related pharmaceuticals or other substances reported to DAWN, based on the classification of Multum Information Services. Multum Information Services is a subsidiary of the Cerner Corporation and a developer of clinical drug information systems and a drug knowledge base. More information is available at http://www.multum.com. In general, the Multum categories follow the therapeutic uses for prescription and over-the-counter pharmaceuticals.

Additional clarification is provided for the following drug categories:

Drug misuse and abuse: A group of ED visits defined broadly to include all visits associated with illicit drugs, alcohol use in combination with illicit drugs or alcohol alone among those younger than 21 years, and nonmedical use of pharmaceuticals. Nonmedical use of pharmaceuticals includes prescription and OTC pharmaceuticals in ED visits that are of the following case types:

Drug-related ED visit: Any ED visit related to recent drug use. This is the definition of a DAWN case effective January 1, 2003. To be a DAWN case, a drug needs only to be implicated in the visit; the drug does not have to have caused the visit. One patient may make repeated visits to an ED or to several EDs, thus producing a number of visits. The number of unique patients involved in the reported drug-related ED visits cannot be estimated, because no direct patient identifiers are collected by DAWN.

Estimate: A statistical estimate is the value of a parameter (such as the number of drug-related ED visits) for the universe that is derived by applying sampling weights to data from a sample.

Hospital emergency department (ED): Only hospitals that meet eligibility criteria for DAWN are recruited to participate. To be eligible, hospitals must be non-Federal, short-stay, general medical and surgical facilities that operate one or more EDs 24 hours a day, 7 days a week, and be located in the United States. Specialty hospitals, hospital units of institutions, long-term care facilities, pediatric hospitals, hospitals operating part-time EDs, and hospitals operated by the Veterans Health Administration and the Indian Health Service are excluded. The universe of EDs is identified from the American Hospital Association's Annual Survey Database. (See also Universe.)

Malicious poisoning: See Drug misuse and abuse.

Metropolitan area: An area comprising a relatively large core city or cities and the adjacent geographic areas. Conceptually, these areas are integrated economic and social units with a large population nucleus. This DAWN publication utilizes areas defined by the Office of Management and Budget (OMB) in June 30, 2003, based on population data from the 2000 decennial Census.

Not otherwise specified (NOS): The catch-all category for substances that are not specifically named. Terms are classified into an NOS category only when assignment to a more specific category is not possible based on information in the source documentation (ED patient charts).

Not tabulated above (NTA): The designation used when categories are not presented in complete detail; smaller units are combined in the NTA category.

Overmedication: See Drug misuse and abuse.

p-value: A measure of the probability (p) that the difference between two estimates could have occurred by chance, if the estimates being compared were really the same. The larger the p-value, the more likely the difference could have occurred by chance. For example, if the difference between two DAWN estimates has a p-value of 0.01, it means that there is a 1% probability that the difference observed could be due to chance alone.

Population: See Universe.

Precision: The extent to which an estimate agrees with its mean value in repeated sampling. The precision of an estimate is measured inversely by its standard error (SE) or relative standard error (RSE). In DAWN publications, estimates with RSEs greater than 50% are regarded as too imprecise to be published. ED table cells where such estimates would have appeared contain the symbol "…" (3 dots). (See also Relative standard error.)

Race/ethnicity: According to the standard protocol issued by OMB in 1997, the race/ethnicity categories on the DAWN data collection forms are as follows:

Despite the detail allowed by these categories, race and ethnicity are often not documented with this level of specificity in patient/decedent records. As a result, categories used to tabulate race and ethnicity data in the publications are:

Rate: A measure of the incidence of drug-related ED visits per 100,000 population. A rate can be calculated for the total population or for any subset defined by characteristics such as age and gender.

Relative standard error (RSE): A measure of an estimate's relative precision. The RSE of an estimate is equal to the estimate's standard error (SE) divided by the estimate itself. For example, an estimate of 2,000 cocaine visits with an SE of 200 visits has an RSE of 10%. The larger the RSE, the less precise the estimate. Estimates with an RSE of 50% or greater are not published by DAWN. (See also Precision and Standard error.)

Sampling: Sampling is the process of selecting a proper subset of elements from the full population so that the subset can be used to make inference to the population as a whole. A probability sample is one in which each element has a known and positive chance (probability) of selection. A simple random sample is one in which each member has the same chance of selection. In DAWN, a sample of hospitals is selected in order to make inference to all hospitals; DAWN uses simple random sampling within strata.

Sampling frame: A list of units from which the ED sample is drawn. All members of the sampling frame have a probability of being selected. A sampling frame is constructed such that there is no duplication and each unit is identifiable. Ideally, the sampling frame and the universe are the same. The sampling frame for the DAWN hospital ED sample is derived from the American Hospital Association (AHA) Annual Survey Database.

Sampling unit: A member of a sample selected from a sampling frame. For the DAWN sample, the units are hospitals, and data are collected for all drug-related ED visits at the responding hospitals selected for the sample.

Sampling weights: Numeric coefficients used to derive population estimates from a sample by adjusting for deviations from the original sample design due to unequal probability sampling, variable nonresponse, and other potential sources of bias.

Seeking detox: This category of drug-related ED visits captures patients seeking substance abuse treatment, drug rehabilitation, or medical clearance for admission to a drug treatment or detoxification unit. They are classified separately because they often reflect administrative practices that vary across hospitals and may vary over time within the same hospital. Seeking detox visits tend to be concentrated in those facilities that operate specialized inpatient units providing substance abuse treatment or detoxification services, and the largest numbers are found in facilities that require medical clearance for entry into such treatment to be granted in their EDs.

Single-drug case: A single-drug case is one in which only one drug was involved. Because multiple substances may be recorded for each DAWN case (see Drug), readers should be cautious in interpreting the relationship between a given drug and the number of associated visits or deaths. For example, if the source record for a patient/decedent documented marijuana use, this does not mean that marijuana was the only drug involved in the visit/death or that the marijuana caused the visit/death. One should always consider whether and how many other drugs were used in combination. Even then, attributing a causal relationship between the visit/death and a particular drug may not be possible. DAWN captures single-drug visits/deaths involving alcohol only if the patient /decedent was younger than age 21.

Standard error (SE): A measure of the sampling variability or precision of an estimate. The SE of an estimate is expressed in the same units as the estimate itself. For example, an estimate of 10,000 visits with an SE of 500 indicates that the SE is 500 visits.

Statistically significant: A difference between two estimates is said to be statistically significant if the value of the statistic used to test the difference is larger or smaller than would be expected by chance alone. For DAWN ED estimates, a difference is considered statistically significant if the p-value is less than 0.05. (See also p-value.)

Strata (plural), stratum (singular): Subgroups of a universe within which separate ED samples are drawn. Stratification is used to increase the precision of estimates for a given sample size, or, conversely, to reduce the sample size required to achieve the desired level of precision. The DAWN ED sample is stratified into metropolitan area cells plus an additional cell for the remainder of the United States. To ensure thorough coverage within metropolitan areas, the universe of hospitals in each is allocated into substrata identified by (a) two types of hospital ownership (public, private) and (b) up to four size categories (measured in terms of annual ED visits), creating up to eight substrata in each metropolitan area stratum. Hospitals in the stratum that covers the rest of the United States are stratified first by Census region, and then by state, type of ownership, and size (also measured in terms of ED visits). A systematic sample is selected from each of the geographic strata.

Suicide attempt: This category of drug-related ED visits captures suicide attempts (e.g., "attempted suicide," "tried to kill self") documented in the medical record in which a drug was involved. Suicidal gestures, thoughts, or ideation, including attempts to "harm" self, are assigned to another case type.

Type of case: A classification used to group similar DAWN cases from the diverse set of all drug-related ED visits. Each case is coded into one and only one category, the first that applies from the following hierarchy: suicide attempt, seeking detox, alcohol only (age < 21), adverse reaction, overmedication, malicious poisoning, accidental ingestion, and other. The rules for assignment of DAWN cases to types of cases are defined in the DAWN ED decision tree in Appendix C.

Universe: The entire set of units for which generalizations are drawn. The universe for the DAWN ED sample is all non-Federal, short-stay, general medical and surgical hospitals in the United States that operate one or more EDs 24 hours a day, 7 days a week. Specialty hospitals, hospital units of institutions, long-term care facilities, pediatric hospitals, hospitals operating part-time EDs, and hospitals operated by the Veterans Health Administration and the Indian Health Services are excluded. The universe of EDs is identified from the American Hospital Association's Annual Survey Database.



APPENDIX C

DAWN DATA COLLECTION AND STATISTICAL METHODS

Introduction

The Drug Abuse Warning Network (DAWN) is a public health surveillance system that has monitored drug-related emergency department (ED) visits to hospitals since the early 1970s. DAWN was initially established by the Drug Enforcement Administration. Then DAWN was transferred to the U.S. Department of Health and Human Services (USDHHS), where the National Institute on Drug Abuse (NIDA) conducted DAWN from 1980 to 1992. Since 1992, the Office of Applied Studies (OAS) of the Substance Abuse and Mental Health Services Administration (SAMHSA), USDHHS, has been responsible for DAWN operations and reporting.

Since its inception, DAWN has relied on data collected from a sample of hospitals. However, over the years, the exact survey methodology has been adjusted to improve the quality, reliability, and generalizability of the information produced by DAWN. When NIDA assumed responsibility for DAWN in 1980, implementation of a sample of hospitals to produce representative estimates for the Nation and for selected metropolitan areas became a priority. This sample, refreshed with annual maintenance, continued to support DAWN estimates for the coterminous United States and 21 metropolitan areas until 2002. By that time, major population shifts and changes in the hospital industry over the preceding two decades made apparent the need for a redesign of the sample of hospitals, which was undertaken as part of a wholesale redesign of most major features of DAWN.

Currently, the DAWN survey relies on a longitudinal probability sample of hospitals located throughout the United States, including Alaska and Hawaii. Hospitals eligible for selection into the DAWN sample must be non-Federal, short-stay, general surgical and medical hospitals located in the United States, with at least one 24-hour ED. This current approach was first implemented in the 2004 data collection year.

DAWN uses the data from the visits classified as DAWN cases in the selected hospitals to calculate various estimates of drug-related visits for the Nation as a whole, as well as for specific metropolitan areas. To calculate these estimates and measure their precision, the DAWN survey requires the application of sampling and weighting methodologies.

This appendix documents the data collection methods and the sampling, weighting, and variance estimation methodologies used to develop estimates for the DAWN data collected for 2004, 2005, and 2006.

Target population

The target population is drug-related ED visits in non-Federal, short-stay, general surgical and medical hospitals in the United States with at least one 24-hour ED.

Hospital sample frame

DAWN uses the American Hospital Association (AHA) Annual Survey Database as the basis for its sampling frame. The AHA maintains an updated national registry of U.S. hospitals that is estimated to have a coverage rate of 99%.17 A health care organization must meet several criteria to be classified as a hospital by the AHA. These include the provision of patient services, diagnostic or therapeutic, for general or specific medical conditions; licensed medical staff; and accreditation by organizations such as the Joint Commission on Accreditation of Health Care Organizations. A hospital is considered to be eligible for inclusion in the DAWN sampling frame if it is a non-Federal, short-stay, general surgical and medical hospital in the United States, with at least one 24-hour ED. Many DAWN hospitals operate multiple EDs.

Determination of DAWN eligibility

A hospital is considered ineligible if any one of the key criteria that define eligibility (non-Federal, short-stay, general surgical and medical hospitals located in the United States, with at least one 24-hour ED) is not met. Only those hospitals that meet all the criteria are considered eligible. For hospitals where critical eligibility data are missing from the AHA database, any one of the nonmissing criteria can render it ineligible. Otherwise, the hospital is considered to have unknown eligibility. For any hospital with unknown eligibility, other variables in the AHA Annual Survey Database are used to determine eligibility. If the hospital's eligibility remains unknown, additional data sources are consulted to determine eligibility.

DAWN data collection

DAWN ED data are collected through a retrospective review of ED medical records for patients treated in the ED. Patients or families are never interviewed. The review of source records is performed by a trained DAWN Reporter in each member facility. Depending on the needs of the facility, the DAWN Reporter may be an employee of the hospital or an employee of the DAWN operations contractor.

For each facility that participates in DAWN, the designated DAWN Reporter reviews all medical records to find ED visits related to drug use. The DAWN Reporter submits an electronic case report to the DAWN system for each ED visit that meets the specific case selection criteria. DAWN Reporters also track, on a copy of the ED registration log, their progress in reviewing the universe of ED visits.

Data items collected by DAWN

The case report form showing all the collected DAWN data items is provided in Figure C1.

Figure C1
DAWN ED case form

Figure C1   D

DAWN features that enhance data quality and reliability

Several methods are used to improve the quality and reliability of DAWN data, including the following:

ED visits eligible for DAWN

A DAWN case is any ED visit related to recent drug use. DAWN includes ED visits associated with substance abuse and misuse, both intentional and accidental. DAWN also includes ED visits related to the use of drugs for legitimate therapeutic purposes. To be a DAWN case, the relation between the ED visit and the drug need not be causal; the drug needs only to be implicated in the visit.

The case criteria are intended to be broad and inclusive, and to have few exceptions. Broad criteria take into account the fact that documentation in medical records varies in clarity and comprehensiveness across hospitals and among clinicians within hospitals. Broad criteria minimize the potential for judgments that could cause data to vary systematically and unexpectedly across reporters and hospitals. In addition, broad criteria are designed to capture a very diverse set of drug-related visits that can be aggregated or disaggregated to serve a variety of analytical purposes and the interests of multiple audiences. In DAWN, only recent drug use is included,18 the reason a patient used a drug is irrelevant, and the criteria are broad enough to encompass all types of drug-related events, including, but not limited to, explicit drug abuse.

There are a few clearly delineated exceptions to the DAWN eligibility criteria. An ED visit is not a DAWN visit if:

Types of cases in DAWN

By design, DAWN's broad case criteria yield a diverse set of visits. To bring order to this heterogeneous mix of ED visits, each visit is assigned to one of eight types, which may be analyzed separately or in purposeful combinations. The eight types of visits are:

DAWN Reporters assign each DAWN case to one, and only one, of the eight case types, based on a series of questions and decision rules. The questions and rules are organized as a decision tree (Figure C2). Starting at the top, each case is assigned to the first case type that applies, even if the case might also meet the rules for a subsequent category. The eight case types were ordered with this in mind.

The final category in the decision tree is called Other and it is reserved for DAWN visits that do not meet any of the rules for classification into one of the first seven types. By design, most cases of drug abuse are classified as case type Other. This approach, which never directly identifies drug abuse, comes from the recognition that medical records frequently lack explicit documentation of substance abuse. This lack of documentation may occur for several reasons. First, the distinctions among use, misuse, and abuse are often subjective. Second, if there is a low index of suspicion for drug abuse in some types of patients, ED physicians may be unlikely to label those types of patients as drug abusers. Third, in many States, insurers may legally deny payment for ED visits related to substance abuse. Thus, financial incentives may be a powerful factor to influence documentation practices.

Drugs included in DAWN

DAWN includes all types of drugs:19

Figure C2
Type of case decision tree

Figure C2   D

To be reportable, a nonpharmaceutical substance must be consumed by inhalation, sniffing, or snorting, and it must have a psychoactive effect when inhaled. An ED visit involving inhalation of a nonpharmaceutical, psychoactive substance and no other drug qualifies as a DAWN case. Carbon monoxide is excluded from the inhalants. Beginning in 2004, cases involving accidental exposures (e.g., exposure to paint fumes while one is painting a closet) are excluded as well.

Hospital participation

For 2006, 205 hospitals submitted data on 269,339 drug-related ED visits that were used for estimation (Tables C1 and C2). The overall weighted response rate was 26.1%. For the 12 oversampled metropolitan areas and divisions, individual response rates ranged from 30.8% in the Houston-Baytown-Sugar Land, TX Metropolitan Statistical Area to 71.2% in the Detroit-Warren-Livonia, MI Metropolitan Statistical Area.

For 2005, 224 hospitals submitted data on 268,128 drug-related ED visits that were used for estimation. The overall weighted response rate in 2005 was 28.9%. There were 13 oversampled areas in 2005 with response rates ranging from 31.1% to 77.3%.

For 2004, 220 hospitals submitted data on 168,841 drug-related ED visits that were used for estimation. The overall weighted response rate in 2004 was 23.9%. There were 13 oversampled areas in 2004 with response rates ranging from 35.3% to 70.8%.

Charts reviewed for drug-related ED visits

DAWN cases are found through a retrospective review of medical records in participating hospitals. Across all participating hospitals in 2006, 9,837,481 charts were reviewed to find the drug-related ED visits that met the DAWN case criteria. Based on the review of charts, 346,946 drug-related visits20 were found and submitted to the DAWN database, a case rate of 3.5%. On average, a DAWN member hospital submitted 1,077 DAWN cases. However, the number of submitted cases varied widely across hospitals, from 7 cases to 6,782 cases (median 820) in a single hospital during 2006.

Across all participating hospitals in 2005, 11,472,887 charts were reviewed to find the drug-related ED visits that met the DAWN case criteria. Based on the review of charts, 374,276 drug-related visits were found and submitted, a case rate of 3.3%. On average, a DAWN member hospital submitted 843 DAWN cases. The number of DAWN cases varied widely, from 1 case to 9,021 (median 525) for a single hospital.

Across all participating hospitals in 2004, 13,299,739 charts were reviewed to find the drug-related ED visits that met the DAWN case criteria. Based on the review of charts, 307,094 drug-related visits were found and submitted, a case rate of 2.3%. On average, a DAWN member hospital submitted 609 DAWN cases. The number of DAWN cases varied widely, from 1 case to 7,485 (median 377) for a single hospital.

Table C1
Data collection year 2006
Geographic area Total eligible hospitals1 Eligible hospitals in sample Responding hospitals in sample Percent
Response rate for sampled hospitals Design weight response rate Visits weighted response rate
Total U.S.2 4,568 544 205 37.7% 24.9% 26.1%
1 Short-term, general, non-Federal hospitals with 24-hour emergency departments, based on the American Hospital Association (AHA) Annual Survey, are eligible for DAWN.
2 Total eligible hospitals in the U.S. include eligible hospitals from metropolitan areas shown and the remainder of the U.S. Therefore, components shown do not sum to the total.
3 Metropolitan Statistical Areas (MSAs) and Metropolitan Divisions follow the standard definitions issued by the Office of Management and Budget in June 2003 (available at http://www.whitehouse.gov/omb/bulletins/b03-04.html), with one exception: for New York, geographic coverage is limited to the subarea comprising the five Boroughs of New York City.
Metropolitan Statistical Areas (MSAs)3
Boston-Cambridge-Quincy, MA-NH MSA      40   29   17 58.6% 58.5% 57.3%
Chicago-Naperville-Joliet, IL-IN-WI MSA      90   74   27 36.5% 37.7% 36.2%
Denver-Aurora, CO MSA      15   15     9 60.0% 60.0% 68.1%
Detroit-Warren-Livonia, MI MSA      37   24   16 66.7% 69.7% 71.2%
Houston-Baytown-Sugar Land, TX MSA      47   42   12 28.6% 28.3% 30.8%
Minneapolis-St. Paul-Bloomington, MN-WI MSA      27   27   10 37.0% 37.0% 44.0%
Phoenix-Mesa-Scottsdale, AZ MSA      28   26   14 53.8% 53.8% 58.1%
San Diego-Carlsbad-San Marcos, CA MSA      16   16     8 50.0% 50.0% 55.7%
Seattle-Tacoma-Bellevue, WA MSA      24   22   10 45.5% 45.5% 55.2%
Metropolitan Divisions and Subareas3
Miami-Miami Beach-Kendall, FL Metropolitan Division of Miami-Fort Lauderdale-Miami Beach, FL MSA      22   16     8 50.0% 46.7% 50.1%
Bronx, Kings, New York, Queens, Richmond Counties of New York-Newark-Edison, NY-NJ-PA MSA      50   39   21 53.8% 46.1% 55.0%
San Francisco-San Mateo-Redwood City, CA Metropolitan Division of San Francisco-Oakland-Fremont, CA MSA      18   18     8 44.4% 44.4% 54.2%

Table C2
Drug-related ED visits, by type of case: 2006
  Unweighted sample data Weighted estimates1 Relative standard error (RSE) 95% Confidence interval
Lower
bound
- Upper
bound
1 These are estimates based on a representative sample of non-Federal, short-stay hospitals with 24-hour EDs in the United States.
2 These are estimates of drugs. A single ED visit may involve multiple drugs.
SOURCE: Office of Applied Studies, SAMHSA, Drug Abuse Warning Network, 2006 (03/2008 update).
Drug-related ED visits
Suicide attempt      11,840         182,805   8.0 154,185 - 211,424
Seeking detox      18,789         118,355 12.1 90,171 - 146,540
Alcohol only (age < 21)        9,940         125,888 12.5 95,087 - 156,690
Adverse reaction      93,507      1,526,010   9.3 1,247,859 - 1,804,161
Overmedication      20,643         285,828   6.2 250,991 - 320,664
Malicious poisoning          750            8,817 13.1 6,546 - 11,088
Accidental ingestion        4,117           79,011   9.1 64,855 - 93,166
Other    109,753      1,115,141 13.0 832,069 - 1,398,213
Total drug-related ED visits    269,339      3,441,855   6.1 3,033,110 - 3,850,600
Total drug misuse/abuse visits    164,334      1,742,887   8.5 1,451,086 - 2,034,688
Total ED visits (all reasons) 8,930,694 113,110,132   0.0   -  
Drugs2
Suicide attempt      25,096        402,907   9.1 331,056 - 474,758
Seeking detox      38,909        243,297 13.3 180,091 - 306,502
Alcohol only (age < 21)        9,940        125,888 12.5 95,087 - 156,690
Adverse reaction    120,016     2,055,783 11.1 1,608,379 - 2,503,188
Overmedication      35,340        506,476   6.6 441,034 - 571,919
Malicious poisoning        1,295          15,293 12.7 11,482 - 19,105
Accidental ingestion        5,200          98,613   9.1 81,048 - 116,178
Other    183,642     1,936,561 10.7 1,531,598 - 2,341,524
Drugs in all drug-related ED visits    419,438     5,384,819   6.3 4,716,771 - 6,052,867
Drugs in all misuse/abuse ED visits    282,938     3,086,984   7.2 2,649,699 - 3,524,268

DAWN data in this publication

For analysis, three categories of ED visits related to drug misuse and abuse were defined. These categories, designed to parallel the approach of the National Survey on Drug Use and Health, are based on:

These three categories are defined by drug and case type as shown in Table C3. Because multiple drugs may be involved in a single visit, these categories are not mutually exclusive. A drug-related ED visit involved 1.6 drugs, on average, in 2004, 2005, and 2006.

Table C3
ED visits related to drug misuse and abuse in DAWN
Type of drug involvement Drugs included Case types included
NOTE: In this publication the case types of suicide attempt and seeking detox are analyzed separately, but for other purposes they might be considered as nonmedical use. Nonmedical use, though, should never include adverse reaction or accidental ingestion cases.
Use of illicit drugs – Cocaine
– Heroin
– Marijuana
– Stimulants (amphetamines and methamphetamine)
– MDMA
– GHB
– Flunitrazepam (Rohypnol)
– Ketamine
– LSD
– PCP
– Other hallucinogens
– Nonpharmaceutical inhalants
– Combinations of illicit drugs
All case types
Use of alcohol – Alcohol in combination with other drug(s)
– Alcohol only in patients under the age of 21
All case types, regardless of age
Cases with alcohol as the sole drug appear only in the following case types for patients under age 21
– Suicide attempts
– Seeking detox
– Alcohol only (age < 21)
Nonmedical use of pharmaceuticals – Prescription and OTC pharmaceuticals
– Dietary supplements
Combination of three case types
– Overmedication (cases of nonmedical use, overuse, misuse lacking explicit documentation of drug abuse)
– Malicious poisoning (cases in which the patient was administered a drug by another for a malicious purpose)
– Case type Other (cases that could not be assigned to another case type; includes documented drug abuse)

Sampling and estimation

DAWN sample design

The redesign of the DAWN system introduced in 2003 altered most of the major features of the DAWN data collection and included a new sample of hospitals that constituted the DAWN. The new sampling plan, fully implemented for the first time for the 2004 estimates, formed a nationally representative panel of hospitals to be followed longitudinally for the indefinite future. Briefly, this new design is a probability-based, stratified, one-stage sample. A complete and accurate list of all hospitals in the United States was drawn and, from that, all hospitals meeting the criteria for the target sample frame were identified. Samples were drawn to provide the capability to make estimates for the Nation as well as select Metropolitan Statistical Areas (MSAs) and divisions (Table C4). Each year the sample frame is updated to account for new hospitals.

The stratified design called for drawing oversamples of hospitals in 48 MSAs; in four of those 48 MSAs, additional oversamples were drawn for a total of nine divisions.21 In effect, there are 53 nonoverlapping geographic areas (44 whole MSAs and nine divisions). (See Table C4 for list of MSAs and divisions22 where oversamples were drawn.) These areas are collectively referred to as oversample areas, or OS areas.

Metropolitan Statistical Areas and subdivisions

In order to accommodate a planned expansion of the metropolitan areas covered by DAWN, a maximum set of metropolitan areas, based on the definitions issued by the Office of Management and Budget (OMB) in June 2003, was selected. Which metropolitan areas to include was a topic of the DAWN redesign.23 Retention of the existing 21 metropolitan areas was important because there was significant demand for estimates for those areas, and addition of the five most populous metropolitan areas in each of the nine Census divisions was deemed important to improve DAWN's geographic and population coverage. This yielded a total of 48 metropolitan areas. For many of the 48 metropolitan areas, the June 2003 definitions resulted in larger metropolitan areas. In some cases, these larger areas represented a merger of previously separate metropolitan areas. However, there continued to be strong interest among users of DAWN statistics in the areas covered by the original 21 metropolitan areas. In order to address the needs of these users, four of the merged areas were subdivided.24 For each of these areas, there was a sample for the metropolitan area, as well as a sample for each subdivision. This would enable DAWN to produce estimates for the metropolitan areas and for the subdivisions. As a result of this process, the final metropolitan-area sample included a total of 53 geographic units: 48 metropolitan areas, 2 subdivisions each for 3 of these metropolitan areas, and 3 subdivisions for one of these metropolitan areas.

Table C4
Oversample (OS) areas in DAWN sample design
* Denotes a legacy area. Two separate legacy areas (New York and Newark) are contained in the New York-Newark-Edison, NY-NJ-PA Metropolitan Statistical Area.
Atlanta-Sandy Springs-Marietta, GA*
Austin-Round Rock, TX
Baltimore-Towson, MD*
Birmingham-Hoover, AL
Boston-Cambridge-Quincy, MA-NH*
Bridgeport-Stamford-Norwalk, CT
Buffalo-Cheektowaga-Tonawanda, NY*
Chicago-Naperville-Joliet, IL-IN-WI*
Cincinnati-Middletown, OH-KY-IN
Cleveland-Elyria-Mentor, OH
Columbus, OH
Dallas-Fort Worth-Arlington, TX*
Denver-Aurora, CO*
Detroit-Warren-Livonia, MI*
Hartford-West Hartford-East Hartford, CT
Honolulu, HI
Houston-Baytown-Sugar Land, TX
Indianapolis, IN
Kansas City, MO-KS
Los Angeles-Long Beach-Santa Ana, CA*
   Los Angeles-Long Beach-Santa Ana, CA – Los Angeles
      division (contains Los Angeles-Long Beach-Glendale,
      CA Metropolitan Division)
   Los Angeles-Long Beach-Santa Ana, CA – Orange
      County division (contains Santa Ana-Anaheim-Irvine,
      CA Metropolitan Division)
Las Vegas-Paradise, NV
Louisville, KY-IN
Memphis, TN-MS-AR
Miami-Fort Lauderdale-Miami Beach, FL*
   Miami-Fort Lauderdale-Miami Beach, FL – Fort
      Lauderdale division (contains Fort Lauderdale-
      Pompano Beach-Deerfield Beach, FL, and West Palm
      Beach-Boca Raton-Boynton Beach, FL, Metropolitan
      Divisions)
   Miami-Fort Lauderdale-Miami Beach, FL – Miami-Dade
      County division (contains Miami-Miami Beach-Kendall,
      FL Metropolitan Division)
Minneapolis-St. Paul-Bloomington, MN-WI*
Nashville-Davidson—Murfreesboro, TN
New Haven-Milford, CT
New Orleans-Metairie-Kenner, LA*
New York-Newark-Edison, NY-NJ-PA*
   New York -Newark-Edison, NY-NJ-PA – New Jersey division
      (contains Middlesex, Monmouth, Ocean, Somerset,
      Essex, Hunterdon, Morris, Sussex, Union, Bergen,
      Hudson, Passaic Counties, NJ, and Pike County, PA)
   New York-Newark-Edison, NY-NJ-PA – New York Suburban
      division (contains Nassau, Putnam, Rockland, Suffolk,
      Westchester Counties, NY)
   New York-Newark-Edison, NY-NJ-PA – New York City,
      5 Boroughs division (contains Bronx, Kings, New York,
      Queens, Richmond Counties, NY)
Omaha-Council Bluffs, NE-IA
Philadelphia-Camden-Wilmington, PA-NJ-DE-MD*
Phoenix-Mesa-Scottsdale, AZ*
Pittsburgh, PA
Portland-Vancouver-Beaverton, OR-WA
Providence-New Bedford-Fall River, RI-MA
Riverside-San Bernardino-Ontario, CA
Rochester, NY
Sacramento-Arden-Arcade-Roseville, CA
Salt Lake City, UT
San Antonio, TX
San Diego-Carlsbad-San Marcos, CA*
San Francisco-Oakland-Fremont, CA*
   San Francisco-Oakland-Fremont, CA – Oakland division
      (contains Oakland-Fremont-Hayward, CA Metropolitan
      Division)
   San Francisco-Oakland-Fremont, CA – San Francisco
      division (contains San Francisco-San Mateo-Redwood
      City, CA Metropolitan Division)
Seattle-Tacoma-Bellevue, WA*
St. Louis, MO-IL*
Tampa-St. Petersburg-Clearwater, FL
Tucson, AZ
Washington-Arlington-Alexandria, DC-VA-MD-WV*
Wichita, KS

Sampled hospitals in each of the OS areas were stratified by hospital size (up to four categories based on volume of ED visits) and ownership type (public and private). (Size categories were determined independently for each OS area.) The stratification plan included an additional geographic construct for the remainder of the United States outside the OS areas. Hospitals in the remainder area were stratified into 24 remainder strata based on four regions (Northeast, South, Midwest, West), hospital size (three size categories based on volume of ED visits), and ownership type (public and private).

To begin, a cross classification was created by categories of ownership type and geographic unit. Within each combination of geographic area and ownership type, the number of hospitals determined the number of unique size categories. If there were three or fewer hospitals, only one size category was defined. If there were four, five, six, or seven hospitals, two size categories were defined. If there were eight or more hospitals, four size categories were defined. In the remainder sample, within each combination of Census region and ownership, there were three size categories. This produced 24 unique strata from which to draw the hospitals for the remainder sample.25

The DAWN national estimates are the sum of the estimates for OS areas and the remainder area. Using a formula, the national estimate is depicted as:

Equation C1   D

where ai is the estimate for OS area i, 53 is the number of OS areas, and b is the remainder area estimate.

It was never expected that DAWN would be able to expand data collection into all 53 OS areas. Instead, the expectation was that DAWN would build up gradually to the number of OS areas its budget could support. The DAWN sample design was conceived to provide the flexibility to change gradually over time in terms of the number of OS areas where data were collected, while providing the statistical infrastructure to enable the production of reliable and representative estimates for the Nation and select OS areas, regardless of their number.

To accomplish this, the DAWN design incorporates an approach whereby a subset of the hospitals within the OS areas was identified a priori as having a dual-purpose in estimation. Referred to as "dual-purpose hospitals," these designated hospitals can contribute to an estimate for the OS area in which they are located or they can contribute to the estimate for the remainder area. Dual-purpose hospitals carry two probabilities of selection (POS) and two stratum identifiers. One POS/stratum is associated with membership in an OS-area sample and the other is associated with membership in the remainder-area sample.26

Figure C3 depicts the initial sample as it was drawn to provide:

Figure C3
Original DAWN sample design

Figure C3   D

For estimation for each data year, the first step is to determine which role each sampled hospital will play in that year's estimates. To do this, the response rates and nonresponse patterns for each OS area are reviewed to determine data quality. Those OS areas with acceptable data quality are allowed to stand on their own as the basis for separate estimates. These are referred to as "stand-alone OS areas." All hospitals in stand-alone OS areas, including those originally designated as being in the dual-purpose subsample, are considered to be "oversample hospitals" in the OS areas, and they contribute to the OS-area estimate using their OS-area POS/stratum.

If it is determined based on response rates and bias analyses that an OS area cannot stand alone, the design provides that the OS area is eliminated as a separate area but becomes part of the remainder area. In this instance:

Figure C4 depicts the assignment of dual-purpose hospitals to either an OS area or the remainder area and the exclusion of OS hospitals outside of stand-alone OS areas that are not designated as dual purpose.

Figure C4
DAWN design in practice

Figure C4   D

After it is determined which OS areas will be stand alone, the DAWN national estimates as reported in this publication are the sum of the estimates for stand-alone OS areas plus the remainder area. Using a formula, the national estimate is depicted as:

Equation C2   D

where ai is the estimate for stand-alone OS area i, 53 is the number of stand-alone OS areas, and b is the remainder area estimate inclusive of dual-purpose hospitals in OS areas that are not stand alone.

It is important to note that the definition of the remainder area and the remainder sample of hospitals is designed to be fluid; hospital membership in the remainder sample changes from year to year depending on the response rates and data quality within the OS areas.

Sample maintenance

Because DAWN is a longitudinal survey that will be used to analyze trends in drug-related ED visits over time, annual updates to the sample are performed to ensure that the sample remains representative of the target population. The initial sample was selected in 2003 from a sampling frame created from the 2001 AHA Annual Survey Database. In every subsequent year, the sampling frame is updated to reflect new, closed, merged, and demerged hospitals, based on updates to the AHA files. These updates include newly eligible hospitals, which are those new hospitals or previously ineligible hospitals that are now eligible. Each year, the newly eligible hospitals are provided the opportunity to be selected into the sample, based on the sampling fraction of the stratum in which the newly eligible hospital is located.

Reduction of bias

Survey error is the extent to which findings from the survey sample differ from those of the population of interest. The statistical methodologies described above are designed to minimize error. There are additional sources of error, often referred to as "bias," that also contribute to overall error. Measuring bias is difficult because it requires accurate knowledge about corresponding population values. The DAWN survey methodology includes proven techniques, practices, and protocols that reduce the potential for introducing bias. For example, clearly defined criteria are used to construct the initial hospital sampling frame. Coverage bias is minimized, because the sampling frame has virtually 100% coverage of the target population. To minimize measurement bias, the individuals who collect data for DAWN are provided with specialized and intensive training; automated methods for data entry are used; and the data are subject to quality reviews at several points in the data collection process. Additional detail on the survey methodologies used to enhance DAWN data quality and reduce bias is provided in an earlier DAWN publication.27

Sample size and sample allocation

DAWN defines precision in terms of the relative standard error (RSE) of an estimate. The RSE is the standard error of the estimate divided by the actual point estimate. DAWN is designed to have RSEs less than or equal to 10% for metropolitan-area estimates, and RSEs less than or equal to 15% for national estimates pertaining to total drug-related visits, cocaine visits, heroin visits, and marijuana visits. As discussed below, these desired precision levels are important drivers for setting sample size targets.

Sample sizes for each geographic area were determined by the area's targeted precision level in combination with the theory of optimal allocation for stratified samples. According to this approach, the variance of the sample estimates will be minimized when the sample size, nh, in each sampling stratum is made proportional to the quantity WhSh /Ch, where Wh is the proportion of sampling units, Sh is the population standard deviation for the parameter being measured, and Ch represents the square root of the cost of sampling in stratum h.

Using these optimum allocation conditions, the minimum required sample sizes necessary to achieve the targeted levels of precision in each DAWN area were calculated using the following general considerations:

In addition to these considerations, sampling rates (i.e., the number of sampled hospitals divided by the number of eligible hospitals) were also subject to the following constraints:

Response rate calculations

In 2006, the initial DAWN sample included 1,286 hospitals divided among 53 OS areas (48 MSAs and nine divisions) and one remainder area. Response rates and nonresponse bias analyses were assessed to determine which of these 53 OS areas could stand alone (Figure C3). Once this determination was made, hospitals that were neither dual-purpose nor located in a stand-alone OS area were treated as if they were not sampled. For 2006, this has the effect of reducing the sample from 1,286 hospitals to 544 hospitals, which is the number used for purposes of computing the unweighted response rates (Table C1).

Of the 53 original oversample areas, a total of 12 areas (nine metropolitan areas and three submetropolitan areas) were determined to be able to stand alone in 2006. A total of 13 areas were determined to be able to stand alone in 2004 and 2005. The 13th OS area was New Orleans-Metairie-Kenner, LA. These determinations yielded a sample size of 556 hospitals in 2004 and 562 hospitals in 2005.

Sampling weights

The DAWN hospitals are selected using stratified simple random sampling with oversampling in selected metropolitan areas. The stratum sample sizes were determined through an optimum allocation process. Sampling weights are first calculated as the inverse of the probability of selection and then adjusted for variable nonresponse and by a procedure known as "poststratification," or benchmark adjustment.

Within-hospital weighting adjustment

Within-hospital nonresponse occurs when a hospital provides incomplete data. To minimize the impact of within-hospital nonresponse, the DAWN weighting plan includes nonresponse adjustment factors that were developed and applied for each month of data collection within each facility. The within-hospital nonresponse adjustment factor is calculated as the total number of ED visits within a month within a facility divided by the total number of reviewed charts for that same facility-month.

The within-hospital weights are applied to the case data by month and by facility. That is, the visit counts for a given facility-month are first summed for each drug and then multiplied by the corresponding within-hospital adjustment factor for that facility-month. The weighted totals are then summed over all facilities and months to give a total weighted visit count for each drug for each hospital.

Weighting adjustment for hospital nonresponse

Hospital-level nonresponse occurs when hospitals fail to provide any data. To minimize the impact of hospital nonresponse, the DAWN weighting plan includes nonresponse adjustment factors that were developed and applied within each weighting class. Weighting classes were formed based on the aforementioned sampling stratification schemes. Within each weighting class, the nonresponse adjustment factor is calculated as the sum of the sampled hospital weights divided by the sum of the weights of the responding hospitals. The hospital nonresponse adjustment factors are checked to make sure the adjustments are within reasonable bounds. If a nonresponse adjustment factor is out of bounds (either too small or too large), adjacent weighting classes are collapsed and new nonresponse adjustment factors are calculated.

When the hospital-level nonresponse adjustment factors are considered final, a nonresponse-adjusted sampling weight was then calculated as the product of the nonresponse adjustment factor and the sampling weight. For each weighting class, a verification check was conducted to ensure that the sum of the nonresponse-adjusted sampling weights was equal to the sum of the sampled hospital weights.

Weighting adjustment for population benchmarks (poststratification)

The DAWN weighting plan also includes a poststratification adjustment factor that reconciles the weighted number of total visits for responding hospitals with the number of total visits from the most recent AHA Annual Survey Database. DAWN used a ratio adjustment within strata to implement this adjustment.

Poststratification strata were formed based on the aforementioned sampling stratification schemes. Within each stratum, the adjustment factor was calculated as the ratio of the AHA count of total visits to the weighted sum of total visits for responding hospitals. The factors were verified to ensure they were within reasonable bounds. If they were out of bounds (either too small or too large), adjacent poststratification strata were collapsed and new poststratification adjustment factors were calculated.

When the poststratification adjustment factors were considered final, a poststratified weight was then calculated. The final weight was calculated as the product of the poststratification adjustment factor and the nonresponse-adjusted sampling weight. For each poststratification stratum, a validity check was conducted to ensure that the sum of the poststratified weighted total visits was equal to the corresponding AHA count of total visits from each stratum.

Special consideration was given to New Orleans because Hurricane Katrina (on August 29, 2005) and its aftermath caused serious disruptions to the operations of hospitals and, consequently, the DAWN data collection process for the remaining four months of the year. Weight adjustments were implemented by referring to the AHA total counts in combination with a case-by-case study of each hospital in the New Orleans metropolitan area.28 Based on these studies, estimates were made of the proportion of the year that each hospital was open and serving the public. These were used to adjust the AHA totals, which in turn serve as input for population benchmark counts for New Orleans.

Total drug-related ED visits

Estimates for the entire universe of DAWN-eligible hospitals in the United States are produced by applying poststratified weights to the data received from the sampled hospitals. Thus, for 2006, 269,339 submitted cases were extrapolated to an estimate of 3,441,855 drug-related ED visits. Considering the margin of error, this estimate may range from 3,033,110 to 3,850,600 drug-related ED visits out of more than 113 million total ED visits estimated for the United States (Table C2).

Calculation of estimates

All estimates produced for this publication were calculated using data that had been weighted according to the plan described above. Estimates for any variable of interest were determined by first summing the case totals within facility-month, applying the within-hospital weight, summing to the hospital level, applying the final hospital weight, and summing over all hospitals.

Variance estimation

Each hospital in the DAWN sample was selected through a random process, which theoretically could have been repeated many times, resulting in many hypothetical samples. "Sampling variance," or the margin of error, refers to the extent to which these samples vary. Two measures of this variability are the standard error (SE) and the relative standard error (RSE), which is defined as the SE of the estimate divided by the estimate itself. The precision of an estimate is inversely related to the sampling variance, as measured by the RSE. The greater the RSE value, the lower the precision.

For example, if there are 10,000 estimated visits involving a given drug, and this estimate has an SE of 500 visits, then the RSE value is 5%:

RSE = SE/Estimate
RSE = 500/10,000
RSE = 0.05, or 5%.

In this publication, "confidence intervals" (CIs) are included in many of the tables and are often cited in the text along with the estimates. The 95% CI is calculated as:

CI = Estimate ± (1.96 × RSE × Estimate)

where 1.96 comes from the table of normal distribution z-values. Ninety-five percent of the normal distribution lies within 1.96 standard deviations of the mean.

Applying the formula to the example above, the 95% CI would be:

10,000 ± (1.96 × 0.05 × 10,000) = 10,000 ± 980.0
Lower limit: 10,000 - 980 = 9,020
Upper limit: 10,000 + 980 = 10,980
95% CI: 9,020 to 10,980.

If repeated samples were drawn from the same population of hospitals, using the same sampling and data collection procedures, the true population values would fall within the confidence interval 95% of the time.

Both between- and within-hospital variance components were accounted for. Within-hospital variance was estimated using a replication strategy by which two random replicates were created within each hospital and the variance between the two replicates represented the within-hospital contribution. Typically, this component was considerably smaller than the between-hospital variance that was calculated as the variance between weighted hospital totals within each stratum.

Variance estimates reported in this publication were determined using Taylor Series Linearization. Variance estimates were calculated using SUDAAN® software.

Standardized rates

Standardized measures are needed to make valid comparisons of estimates across age and gender categories. For age in particular, the size of the underlying population differs considerably across age groups; for example, the number of individuals aged 18 to 20 in the United States is much lower than the number of individuals aged 35 to 44. All other factors being the same, a higher estimate of ED visits would be expected to occur naturally for the group that is larger in the population.

To take the size of the underlying population into account, rates of ED visits per 100,000 population were calculated using population data from the U.S. Bureau of the Census.29

For each age and gender category, the estimate for a category was divided by the population for that category, which was then divided by 100,000. For example, consider an estimate of 1,000 visits for an age group of 1,000,000 persons, and an estimate of 1,000 visits for an age group of 500,000 persons. The rates would be calculated as:

1,000 / (1,000,000/100,000) = 1,000/10
= 100 visits per 100,000 population

1,000 / (500,000/100,000) = 1,000/5
= 200 visits per 100,000 population.

Population estimates used to generate rates for 2006 are provided in Table C5.

Table C5
Population by age and gender: 20061
Gender and age Total United States Males Females
Total 302,225,862 149,002,083 153,223,779
1 Population estimates for 2006 are, as of 6/9/2008, from the U.S. Bureau of Census Postcensal Resident Population National Population Dataset, National estimates by demographic characteristics - single year of age, sex and race, and Hispanic Origin, Monthly Population Estimates. Link: http://www.census.gov/popest/datasets.html. File: NC-EST2007-ALLDATA-R-File14.csv.
0-5 years   24,640,694   12,601,585   12,039,109
6-11 years   23,807,562   12,174,360   11,633,202
12-17 years   25,447,520   13,037,107   12,410,413
18-20 years   12,674,580     6,507,886     6,166,694
21-24 years   16,977,014     8,780,282     8,196,732
25-29 years   21,221,621   10,871,501   10,350,120
30-34 years   19,655,279     9,974,102     9,681,177
35-44 years   43,297,681   21,691,759   21,605,922
45-54 years   43,932,378   21,623,741   22,308,637
55-65 years   32,737,374   15,786,874   16,950,500
65 years and older   37,834,159   15,952,886   21,881,273

Standardized rates were not calculated for race and ethnicity subgroups, because the race/ethnicity categories available to DAWN are much less detailed and contain considerably more missing data than the race and ethnicity categories in the Census data. Appendix D describes the race and ethnicity data reported for DAWN.

Determination of significant differences between years

Comparisons in the estimates of ED visits between years are presented in the form of percentage differences. These are calculated as the 2006 estimate minus the 2004 estimate divided by the 2004 estimate. For shorter term comparisons, these are calculated as the 2006 estimate minus the 2005 estimate divided by the 2005 estimate. The result is presented as a percentage, which is shown only if the difference between the two years is statistically significant. Tests for the significance of differences between two years consider the variance of each year's estimate and the covariance between the two. Thus, hospitals that appear in both samples and provide data in both years contribute to the covariance and, thus, decrease the overall sampling variance beyond the combined contribution of the two samples. The variance estimation process used to establish significance takes into account this overlap between the two annual samples.

Publication criteria

DAWN can produce estimates for thousands of drugs, patient characteristics, and visit characteristics, but some of these estimates are too imprecise, too small, or based on too little data to be reliable. In these situations, the estimate was replaced by three dots (…) in the published table. Estimates were suppressed (i.e., not published) according to the following rules:

When the RSE is greater than 50%, the lower bound of the 95% CI approaches or includes the value zero. A CI that includes zero means that the estimate is not statistically different from zero at this precision level.

Estimates this small constitute rare events, which are based on a small number of cases and have precision levels that are difficult to quantify. In many instances, such rare events have variances so large that the estimate would be suppressed because of its RSE alone. Rare events that meet RSE criteria for publication are nonetheless based on very little data and are deemed too unreliable for publication.

There are some estimates with an RSE equal to zero. This occurs when the number of ED visits being estimated is small and all the hospitals contributing to that estimate were selected with certainty, that is, their sampling probability is unity. Strictly speaking, there is no sampling error in such situations and the RSE is equal to zero. These results occur almost exclusively in situations with small numbers of ED visits, where the absence of any sampled hospital data is due to nonresponse and the small number of hospitals contributing to the estimates. In these situations, the necessary data are not available to approximate sampling errors.



APPENDIX D

RACE AND ETHNICITY IN DAWN

In October 1997, the Office of Management and Budget (OMB) issued a revised standard protocol for race and ethnicity categories used in Federal data collection systems.30 The new protocol permitted separate reporting of race and Hispanic ethnicity, and it incorporated the ability to capture more than one race for an individual, a few modifications in nomenclature (e.g., "black" was changed to "black or African American"), division of certain categories ("Asian or Pacific Islander" was split into two categories, "Asian" and "Native Hawaiian or Other Pacific Islander"), and elimination of the "other" category. For data collections such as DAWN, where self-identification of the individual is not feasible (no patient is interviewed for DAWN), the OMB protocol also permitted a combined format, whereby race and Hispanic ethnicity would be recorded in a single data item, which could still record multiple entries for race and/or Hispanic ethnicity. The single data item for race and ethnicity is shown in the DAWN ED case form that has been used since 2003 (Appendix C, Figure C1).

Despite the increased detail allowed by the new categories and the provision for multiple entries, the actual race/ethnicity data extracted from source records and submitted to DAWN is quite limited. This is because the source documents (i.e., the ED medical records from which DAWN data are abstracted) rarely contain such detailed information on race/ethnicity of patients.

For reference, estimates of drug-related ED visits by race/ethnicity are presented in Table D1. This analysis, which is based on the most detailed coding of race/ethnicity in DAWN case reports, reveals that estimates for the following categories are too small to be meaningful:

Therefore, in the tables of estimates in this and other DAWN publications we have retained a more limited set of categories: white, black, and Hispanic. A fourth category, called "Race/ethnicity not tabulated above (NTA)," is used to tabulate those categories that are too small to report independently.31 All cases reported to DAWN as Hispanic or Latino ethnicity are tabulated as Hispanic race/ethnicity, regardless of race.

This lack of detailed race and ethnicity data in DAWN case reports also prevents us from generating rates per 100,000 population for race and ethnicity categories. Data from the 2000 decennial Census were collected and are being tabulated according to the revised race and ethnicity protocol and are therefore incompatible with DAWN estimates.

Table D1
Drug-related ED visits, by detailed race/ethnicity: 2006
Race/ethnicity Estimated visits1,2
Total drug-related ED visits 3,441,855
1 These are estimates of ED visits based on a representative sample of non-Federal, short-stay hospitals with 24-hour EDs in the United States.
2 Three dots (…) indicate that an estimate with an RSE greater than 50% or a quantity less than 30 has been suppressed.
SOURCE: Office of Applied Studies, SAMHSA, Drug Abuse Warning Network, 2006 (03/2008 update).
One race/ethnicity 3,411,056
White 2,132,810
Black/African American    524,420
Hispanic    298,668
Asian        5,765
American Indian/Alaska Native      29,396
Native Hawaiian/Other Pacific Islander        3,875
Race unknown    416,122
Two races/ethnicities      30,798
White + Black/African American           717
White + Hispanic      28,394
White + Asian           110
White + American Indian/Alaska Native             32
Black/African American + Hispanic           699
Black/African American + Asian              …
Black/African American + American Indian/Alaska Native           216
Hispanic + Asian              …
Hispanic + American Indian/Alaska Native           366
Asian + American Indian/Alaska Native              …
Three races/ethnicities              …
White + Black/African American + Hispanic              …
White + Hispanic + Asian              …
White + Asian + Native Hawaiian/Other Pacific Islander              …

End Notes

1 The 95% confidence interval (CI) accounts for the margin of error of the estimate. It indicates, with a high degree of confidence, that the true population value was between 1,451,086 and 2,034,688 drug-related ED visits.
2 That is, the rates for the age categories 18 to 20, 21 to 24, 25 to 29, 30 to 34, 35 to 44, and 45 to 54 were not significantly different.
3 Though a drug was implicated in each visit, these attempts are not limited to drug overdoses.
4 That is, patients with a history of drug use (and no recent use) are excluded.
5 The classification of drugs used in DAWN is derived from the Multum Lexicon, © 2007, Multum Information Services, Inc. The classification was modified to meet DAWN's unique requirements (2007). The Multum Licensing Agreement governing use of the Lexicon is provided in Appendix A.
6 To be reportable, a nonpharmaceutical substance must be consumed by inhalation, sniffing, or snorting and must have a psychoactive effect when inhaled. An ED visit involving inhalation of a nonpharmaceutical, psychoactive substance qualifies as a DAWN case even if no other drug was present. Carbon monoxide is excluded from the inhalants. Since 2004, cases involving accidental exposures (e.g., exposure to paint fumes while painting a closet) have been excluded as well.
7 ED visits related to alcohol use alone are excluded for patients aged 21 and over.
8 Excluded are suicide attempts involving pharmaceuticals, accidental ingestions, visits for patients seeking detoxification services or entry into a substance abuse treatment program, and visits associated with the therapeutic use of pharmaceuticals.
9 For DAWN, 2003 was a transition year: 2003 data reflected some of the new features (e.g., the expanded case criteria) but also some of the old (e.g., the old sample of hospitals). Full-year estimates were not published for 2003, and the estimates that were published are not comparable to those from prior or subsequent years.
10 Population estimates for 2006 are, as of 6/9/2008, from the U.S. Bureau of Census Postcensal Resident Population National Population Dataset, National estimates by demographic characteristics – single year of age, sex and race, and Hispanic Origin, Monthly Population Estimates. Link: http://www.census.gov/popest/datasets.html. File: NC-EST2007-ALLDATA-R-File14.csv.
11 These three categories of ED visits are not mutually exclusive, and the sum of the estimates is greater than the total number of drug misuse/abuse visits. See Appendix C for additional detail on the type of ED visits included in each category.
12 ED patients over the age of 21 for whom alcohol was the only drug associated with their ED visits are not considered DAWN cases.
13 DAWN cases are identified through a retrospective review of medical charts. Given the limitations of medical record documentation, we have concluded that distinguishing misuse from abuse reliably is not feasible.
14 Taking less than the prescribed or recommended dose is not considered "nonmedical use."
15 This includes only single-ingredient formulations. Many multi-ingredient pharmaceuticals containing diphenhydramine are classified elsewhere, e.g., as respiratory agents.
16 In this publication, drugs are classified using the Drug Reference Vocabulary that was current as of May 2007.
17 AHA Annual Survey Database, Fiscal year 2001 Health Forum LLC, Copyright 2003, One North Franklin Street, Chicago, IL 60606.
18 That is, patients with a history of drug use (and no recent use) are excluded.
19 The classification of drugs used in DAWN is derived from the Multum Lexicon, © 2007, Multum Information Services, Inc. The classification was modified to meet DAWN's unique requirements (2007). The Multum Licensing Agreement governing use of the Lexicon is provided in Appendix A and can be found on the Internet at http://www.multum.com.
20 For 2004-2006, more hospitals participated in DAWN than were used in estimation. Therefore, the number of drug-related ED visits from all participating hospitals exceeded the number used for estimation.
21 The four MSAs where samples were drawn for divisions are Los Angeles, Miami, New York, and San Francisco. The division definitions used by DAWN follow Census Bureau definitions of Metropolitan Divisions, except in New York where the three submetropolitan areas were defined uniquely based on local input.
22 MSAs and Metropolitan Divisions follow the standard definitions issued by the Office of Management and Budget in June 2003 (available at http://www.whitehouse.gov/omb/bulletins/b03-04.html and http://www.census.gov/population/www/estimates/metrodef.html).
23 Substance Abuse and Mental Health Services Administration, Office of Applied Studies. Drug Abuse Warning Network: Development of a New Design (Methodology Report). DAWN Series M-4, DHHS Publication No. (SMA) 02-3754, Rockville, MD, 2002.
24 When metropolitan areas were redefined in June 2003 based on data from the 2000 decennial Census, several legacy MSAs were merged with other MSAs to form new, much larger MSAs. However, a strong constituency of DAWN data users still needed estimates for the pre-merger areas. Because of this, four of the 48 metropolitan areas-Los Angeles, Miami, New York, and San Francisco-were subdivided into a total of nine divisions, corresponding to the constituents' areas of interest.
25 Four Census regions times two ownership categories times three size categories equals 24 strata.
26 In addition, a portion of hospitals in the nine oversampled divisions were identified a priori to serve in their MSA-level oversample and were assigned an OS area level POS/stratum for that third purpose. Therefore, hospitals in the four MSAs with division-level oversampling can have up to three nonzero POS/strata: (1) a POS/stratum for membership in the MSA; (2) a POS/stratum for membership in the division; and (3) a POS/stratum for membership in the remainder area.
27 See Appendix B, Technical Notes: Changes to Improve the Quality of DAWN Data in: Substance Abuse and Mental Health Services Administration, Office of Applied Studies. Drug Abuse Warning Network 2003: Interim National Estimates of Drug-Related Emergency Department Visits. DAWN Series D-26, DHHS Publication No. (SMA) 04-3972, Rockville, MD, 2004.
28 Information provided by the Louisiana Hospital Association, the Louisiana Public Health Institute, the City of New Orleans Health Department, and available at numerous websites maintained by individual hospitals, news organizations, and State and Federal agencies was invaluable in conducting this assessment. We are grateful for their assistance.
29 Population estimates for 2006 are, as of 6/9/2008, from the U.S. Bureau of Census Postcensal Resident Population National Population Dataset, National estimates by demographic characteristics – single year of age, sex and race, and Hispanic Origin, Monthly Population Estimates. Link: http://www.census.gov/popest/datasets.html. File: NC-EST2007-ALLDATA-R-File14.csv.
30 See Office of Management and Budget, Revisions to the Standards for the Classification of Federal Data on Race and Ethnicity, 62 Fed. Reg. 58,782 (October 30, 1997).
31 One exception is that, if two races are reported and the second is reported as unknown, the episode is coded for the known race.

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