Drug Abuse Warning Network, 2009:
Methodology Report

U.S. DEPARTMENT OF HEALTH AND HUMAN SERVICES
Substance Abuse and Mental Health Services Administration
Center for Behavioral Health Statistics and Quality

CONTENTS

Acknowledgments

Introduction

1. Overview of DAWN Data Program
1.1 Overview of DAWN
1.2 Hospitals eligible to participate in DAWN
1.3 ED visits eligible for inclusion in DAWN
1.4 Drugs reported for DAWN ED visits
1.5 DAWN estimates of ED visits
1.6 Uses of DAWN data
1.7 DAWN reports, tables, and data files

2. Information Collected by DAWN
2.1 ED visits eligible for DAWN
2.2 Case types in DAWN
2.3 Key data items
2.3.1 Patient demographics
2.3.2 Visit characteristics
2.3.3 Drugs and drug categories
2.3.4 Visit disposition

3. Development of the ED Component of DAWN
3.1 DAWN ED sample design
3.1.1 Sample frame of hospitals
3.1.2 Metropolitan areas represented in DAWN
3.1.3 Metropolitan-level stratification
3.1.4 Hospital size and ownership stratification
3.1.5 Sample size and sample allocation
3.2 Data collection procedures
3.2.1 Review of ED medical records
3.2.2 Selection of ED medical records
3.3 Data preparation
3.4 ED data and statistical processing
3.4.1 ED data processing
3.4.2 DAWN sample maintenance
3.4.3 Weights and adjustments
3.4.4 Sequential process of developing and applying weights and adjustments

4. DAWN Publications and Data Dissemination
4.1 Analytic groups
4.2 Drug lists
4.3 Estimates of visits and drugs
4.4 Standardized rates
4.5 Measures of precision and error
4.6 Suppression
4.7 Cross-year comparisons

5. Quality Assurance/Quality Control
5.1 Minimization of nonsampling error
5.1.1 Maintaining data quality during data collection and data preparation
5.1.2 End-of-year data quality review
5.2 Minimization of sampling error
5.3 QC on released reports and tables

6. Data Limitations
6.1 Limitations of survey data
6.2 Limitations of using extant medical records
6.3 Limitations on toxicology test finding

List of Figures

Figure 1. Type of case decision tree
Figure 2. DAWN ED case form

List of Tables

Table 1. Metropolitan areas with published DAWN estimates of drug-related emergency department visits for 2009
Table 2. DAWN analytic groups
Table 3. Estimates of visits compared with estimates of drugs involved, 2009
Table 4. Data items in the data quality review spreadsheet

List of Appendices

Appendix A History of DAWN
Appendix B Glossary of DAWN Terms, 2009 Update

INTRODUCTION

This publication describes the methodologies used by the Drug Abuse Warning Network (DAWN), a program of the Center for Behavioral Health Statistics and Quality (CBHSQ), Substance Abuse and Mental Health Services Administration (SAMHSA), to collect, prepare, and analyze information on drug-related emergency department (ED) visits in the United States. An understanding of the methodology behind the collection and processing of DAWN data allows data users to better evaluate the validity, representativeness, and meaning of the findings. The methods described here were initiated in 2004 and are current as of 2009. Prior to 2004, DAWN methodology was substantially different. Therefore, earlier findings cannot be compared with findings from 2004 through 2009.

This report is organized into eight parts:

• Overview of the DAWN data program—Brief summary of DAWN and its purpose.
• Information collected by DAWN—What constitutes a drug-related ED visit and the data items collected for each visit.
• Development of the ED component of DAWN—How DAWN data on drug-related ED visits are collected and processed to make representative national and metropolitan area estimates using survey data.
• DAWN publications and data dissemination—How DAWN data are organized, summarized, and presented to address different statistical and analytic goals.
• Quality assurance/quality control—Methods and procedures used to ensure DAWN data are as accurate, precise, and reliable as possible.
• Data limitations—DAWN collects data on ED visits from a sample of hospitals and relies solely on existing medical records maintained by the hospitals; as a result, there are some limitations to consider when interpreting results.
• History of DAWN—How DAWN came into existence and has been maintained for almost 40 years.
• Glossary of DAWN terms, 2009 update—Resource to help understand the nature of DAWN visits and DAWN terminology.

Additional information about DAWN is provided on the DAWN Web site.¹ Available at the site are

• annual reports for 2004 through 2009 that summarize overall DAWN findings;
• short reports that highlight DAWN findings on specialized topics or for specific metropolitan areas;
• detailed tables of DAWN estimates for 2004 through 2009 for the Nation and select metropolitan areas;
• methodology and design reports;
• background information on SAMHSA, CBHSQ, and the contractors responsible for DAWN data collection and analysis; and
• links to other SAMHSA Web sites.

1. OVERVIEW OF DAWN DATA PROGRAM

1.1 Overview of DAWN

The Drug Abuse Warning Network (DAWN) is a public health surveillance system that continuously monitors drug-related visits to hospital emergency departments (EDs).² Annually, DAWN produces estimates of drug-related visits to hospital EDs for the Nation as a whole and for selected metropolitan areas. DAWN is used to monitor trends in drug misuse and abuse, identify the emergence of new substances and drug combinations, assess health hazards associated with drug abuse, and estimate the impact of drug misuse and abuse on the Nation's health care system.

DAWN employs a multistage sampling design for the selection of EDs for analysis. Stratified simple random sampling with oversampling in selected metropolitan areas is used to select the hospitals. Days of the month are then systematically selected from within a hospital, and, finally, a census of ED visits is selected for these days.

1.2 Hospitals eligible to participate in DAWN

DAWN's target sample frame consists of all non-Federal, short-stay, general medical and surgical hospitals in the United States that have one or more EDs open 24 hours a day.

1.3 ED visits eligible for inclusion in DAWN

A DAWN case is any ED visit involving recent drug use. DAWN cases are identified by the systematic review of ED medical records in participating hospitals. DAWN captures both ED visits that are directly caused by drugs and those in which drugs are a contributing factor but not the direct cause of the ED visit. These criteria encompass all types of drug-related events, including accidental ingestion and adverse reaction, as well as drug misuse or abuse.

1.4 Drugs reported for DAWN ED visits

DAWN collects data on all types of drugs—illegal drugs, prescription and over-the-counter medications, dietary supplements, and both pharmaceutical and nonpharmaceutical inhalants. DAWN notes whether alcohol is involved in addition to drug(s) for patients of all ages. Because alcohol is considered an illicit drug for minors, alcohol abuse without the involvement of other drugs is considered a drug-related ED visit for patients under the age of 21. DAWN does not report current medications (i.e., medications and pharmaceuticals taken regularly by the patient as prescribed or indicated) that are unrelated to the ED visit.

DAWN classifies drugs using a modified version of the Multum Lexicon, © 2011, a drug vocabulary and classification tool originated by Multum Information Services, Inc. DAWN has adapted the Lexicon to allow for the inclusion of illegal drugs, inhalants, and alternative medicines that are reported to DAWN.

1.5 DAWN estimates of ED visits

DAWN produces weighted estimates of drug-related ED visits that are the result of drug misuse or abuse, adverse reactions to drugs, and accidental ingestion of drugs. Among visits resulting from drug misuse or abuse, separate estimates are made of visits involving illicit drugs, nonmedical use of pharmaceuticals, and alcohol. Estimates are also made of ED visits resulting from drug-related suicide attempts, ED visits made by patients seeking detoxification services, and visits involving alcohol for patients under the age of 21. For each of these types of visits, estimates are available by patient gender, age group, and race/ethnicity. Estimates are also provided for each visit's disposition (e.g., treated and released, admitted to the hospital intensive care unit, died). For each of these categories of visits, estimates are made of the different types of drugs involved.

These sets of estimates are prepared for the Nation as a whole and for selected metropolitan areas where hospital participation was high enough to produce reliable results.

1.6 Uses of DAWN data

DAWN is the only data system providing estimates of the number of ED admissions associated with drug misuse and abuse and the particular drugs involved both for the United States as a whole and also for selected metropolitan areas. These estimates are used to monitor trends in major substances of abuse (e.g., heroin, cocaine, marijuana), to assess alcohol use by minors that results in ED visits, to identify emerging new drugs of abuse (e.g., synthetic cannabinoids, methamphetamine), to identify the abuse potential of prescription and over-the-counter drugs to better inform labeling and scheduling decisions, and to reveal changing patterns of drug abuse. Furthermore, DAWN is the only national data collection system on drug abuse with the capacity to monitor specific and relatively infrequently used substances of abuse (such as club drugs, phencyclidine [PCP], or medications used to treat attention deficit hyperactivity disorder) as they emerge and diffuse across population groups and geographic areas.

DAWN is a major component of the Nation's capacity to monitor trends in the morbidity and mortality associated with drug misuse and abuse. It is used by national, State, and local professionals to monitor trends in the health hazards associated with substance abuse and to identify emerging trends and changing patterns of drug abuse. DAWN offers data of value to policymakers, law enforcement officers, pharmacologists, and health professionals. The data are used by the White House Office of National Drug Control Policy to monitor national trends; the Drug Enforcement Administration for surveillance, diversion control, and intelligence; and the Food and Drug Administration and pharmaceutical industry to conduct postmarketing surveillance of prescription and over-the-counter pharmaceuticals, actively monitor adverse events associated with medications that are new or old, and assess the abuse potential for labeling and scheduling decisions. State and local professionals, including law enforcement and the Community Epidemiology Work Group, use DAWN to assess changes in local trends and patterns of drug use. The Substance Abuse and Mental Health Services Administration (SAMHSA) itself uses DAWN to target program resources to areas of greatest need and to monitor adverse events associated with buprenorphine treatment for opiate addiction.

1.7 DAWN reports, tables, and data files

The DAWN Web site provides a complete listing of all publicly available reports and tables using DAWN data.³ Public use files are expected to be available on the Substance Abuse and Mental Health Data Archive (SAMHDA) site in 2011.⁴

2. INFORMATION COLLECTED BY DAWN

2.1 ED visits eligible for DAWN

A Drug Abuse Warning Network (DAWN) case is any emergency department (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 as directed for legitimate therapeutic purposes. To be a DAWN case, the drug must be implicated in the ED visit, but it does not need to be the direct cause. The reason a patient used a drug is not a factor in determining whether the ED visit is a DAWN case.

The DAWN visit eligibility criteria are intended to be broad and inclusive and to have few exceptions. They take into account the fact that documentation in medical records varies in clarity and comprehensiveness across hospitals and among clinicians within hospitals. The criteria are designed to minimize the potential for judgments that could cause data to vary systematically and unexpectedly across different data collectors and hospitals. In addition, the criteria allow for the capture of a 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.

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

• there is no evidence of recent drug use;
• the patient left the ED without being treated;
• the patient consumed a nonpharmaceutical substance but did not inhale it;
• the patient has a history of drug use but no recent use;
• alcohol is the only substance involved and the patient is an adult (aged 21 or older);
• drugs mentioned in the ED record are not related to the ED visit (e.g., list of current medications);
• drugs identified in toxicology testing are not related to the visit, and the medical record does not contain any additional drug-related information that would make the visit a DAWN case; or
• the patient is being treated as a consequence of undermedication (i.e., taking too little of a drug).

2.2 Case types 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, DAWN Reporters⁵ assign each visit to one of eight case types. The eight case types are as follows:

• suicide attempt;
• seeking detoxification;
• alcohol only, in patients younger than 21;
• adverse reaction;
• overmedication;
• malicious poisoning (e.g., drug-facilitated sexual assault, product tampering);
• accidental ingestion; and
• other.

Each ED visit is assigned to a single case type. Because many ED visits meet the criteria for more than one case type, the case types are assigned based on an algorithm depicted in the "DAWN Decision Tree" (Figure 1). Each ED visit is assigned to the first applicable case type. To assist DAWN Reporters with case assignment, a series of questions and decision rules is included with the Decision Tree; detailed instructions are included in the ED Reference Guide.⁶

3. DEVELOPMENT OF THE ED COMPONENT OF DAWN

3.1 DAWN ED sample design

The redesign of the Drug Abuse Warning Network (DAWN) system introduced in 2003 gave DAWN the capability to make statistically valid annual estimates of drug-related ED visits for the Nation and selected metropolitan areas. A new sample of hospitals was drawn through stratified simple random sampling from among the universe of eligible hospitals in the Nation; oversampling was conducted in selected metropolitan areas.¹⁰ Each year, days of the month are systematically selected for each hospital, and all ED visits for these days are reviewed for eligibility as DAWN cases. Data collection following the new sampling plan was fully implemented for the first time in the 2004 data collection year, and the original sample of hospitals has been followed longitudinally since then. Each year, new hospitals are given the opportunity to be sampled into the longitudinal panel of hospitals.

3.1.1 Sample frame of hospitals

After a thorough investigation of alternatives, DAWN chose to use the American Hospital Association (AHA) Annual Survey Database (ASDB) to identify all hospitals in the United States. A sampling frame was built from among all hospitals on the 2001 AHA ASDB meeting the DAWN criteria for eligible hospitals—non-Federal, short-stay, general medical and surgical hospitals in the United States that have one or more EDs open 24 hours a day, 7 days a week.¹¹ A probability sample proportionate to the number of ED visits in each facility was drawn from among eligible hospitals.

3.1.2 Metropolitan areas represented in DAWN

As part of the redesign, samples were drawn to provide the capability to make estimates for the Nation and selected metropolitan areas. These areas are referred to as oversampled areas (OS areas) or DAWN metropolitan areas. Two goals guided the selection of the DAWN metropolitan areas. The first was to preserve the ability to represent the 21 areas that had been part of DAWN since its inception. The second was to improve population and geographic coverage beyond the 21 legacy areas. Accordingly, the design ensured representation of the original 21 legacy areas plus the 5 most populous Metropolitan Statistical Areas (MSAs) in each of the 9 census divisions. Oversamples were selected in a total of 48 MSAs; in 4 of those 48 MSAs, additional oversamples were drawn to allow reporting for subareas within those MSAs. Resources available to DAWN have allowed for data collection in only a portion of the OS areas. During data collection year 2009, data were collected from a representative sample of hospitals in the Nation and 15 OS areas. Table 1 lists the OS areas that had sufficient participation in 2009 to allow DAWN to publish reliable estimates of drug-related ED visits.

4. DAWN PUBLICATIONS AND DATA DISSEMINATION

The Drug Abuse Warning Network (DAWN) issues both regular and ad hoc reports, tables, and related data products. This section describes the characteristics of these data products and the standards DAWN uses to compile and present estimates.

4.1 Analytic groups

For the purpose of analysis, DAWN developed a set of categories to use when reporting on emergency department (ED) visits. Referred to as "analytic groups," these categories combine visits with similar characteristics to produce summary statistics. The DAWN analytic groups and their definitions are provided in Table 2. The analytic groups fall into one of three types: all visits (regardless of intent), visits where there is an indication of some type of drug misuse or abuse, and visits where there is no indication of misuse or abuse.

Because of DAWN's focus on drug misuse and abuse, this topic is addressed by several analytic groups, including all drug misuse or abuse, all visits involving illicit drugs, visits involving nonmedical use of pharmaceuticals, visits involving alcohol for patients of all ages, and visits involving alcohol for patients under the age of 21. Also isolated for analysis are visits involving drug-related suicide attempts and visits made by patients seeking detoxification services. The subgroups under "Drug misuse or abuse" in Table 2 are not mutually exclusive because a single visit can involve multiple types of drugs. For example, an ED visit involving marijuana and oxycodone would be grouped with other visits involving illicit drugs, as well as with visits involving nonmedical use of pharmaceuticals.

Annually DAWN produces comprehensive sets of tables, the DAWN Trend Tables, that provide estimates of drug-related ED visits by type of drug, patient gender and age, visit disposition, and other characteristics for the current year and all prior years. A complete set of tables is produced for each analytic group listed in Table 2. Each set is reproduced for the Nation and for metropolitan areas with sufficiently high levels of participation (see Table 1). A more detailed description of the DAWN Trend Tables is provided in the Guide to Drug Abuse Warning Network Trend Tables, 2009, which is available at the DAWN Web site.¹⁸

5. QUALITY ASSURANCE/QUALITY CONTROL

Survey error, also referred to as bias, is the extent to which findings from the survey sample differ from those of the population of interest. Error can be introduced at any stage in the survey process, from building the sample frame to reporting estimates. This section documents methodologies employed by the Drug Abuse Warning Network (DAWN) to help ensure that published estimates are representative, accurate, and reliable.

5.1 Minimization of nonsampling error

To control the nonsampling error components and produce data of high quality, DAWN has a well-defined data quality assurance program and a continuous data quality control (QC) program. The two primary components of the data QC program are (1) the extensive and continuous monitoring of data quality during data collection and processing and (2) an annual data quality review (DQR) meeting that assesses data quality from a broad perspective (i.e., a review of the annual data for each of the individual emergency departments [EDs] and in relation to other EDs).

5.1.1 Maintaining data quality during data collection and data preparation

Measures used to monitor data quality during data collection include but are not limited to onsite quality audit reviews and quarterly standardized error feedback reports. In addition to those measures, DAWN employs a custom-built software system (eHERS) to collect DAWN data. eHERS, which provides automated prompts to ensure that DAWN Reporters collect complete data, is populated with the detailed codes that are used to record drugs, race/ethnicity, visit disposition, and other codified variables. It performs real-time data validation checks to ensure that the data are within valid ranges and consistent with other information collected for the visit. eHERS also checks across visits to ensure that visits are not entered multiple times and follows a procedure to resolve conflicts if multiple entries are detected.

5.1.2 End-of-year data quality review

Before data are weighted, researchers responsible for the collection (the DAWN operations contractor) and analysis (data analysis contractor) of DAWN data meet with staff from the Substance Abuse and Mental Health Services Administration's Center for Behavioral Health Statistics and Quality to review the quality of the data. This process is referred to as the DQR.

Before the DQR meeting, the DAWN operations contractor prepares an electronic file that summarizes what is known about the quality of the data that was collected in the prior year. The DQR spreadsheet contains descriptive information including facility ID, facility name, oversampled area name, stratum, eligibility, subsampling information, and participation status. In addition, the DQR spreadsheet includes summary data for each of the fields for each ED by month, as shown in Table 4. Review of these data items reveals what portion of ED visits in each hospital for each month were evaluated for inclusion in DAWN. Depending on the pattern of missing data for an ED, the group comes to a consensus about whether to delete, adjust, or impute the count of eligible ED visits, the count of medical charts reviewed, and the count of identified DAWN cases in each month of each ED for the reporting year. These counts are vital to developing accurate within-facility adjustment factors for each month for each facility.

6. DATA LIMITATIONS

6.1 Limitations of survey data

Information on drug-related emergency department (ED) visits in the Drug Abuse Warning Network (DAWN) is based on a sample and is, therefore, subject to sampling variability. The standard error measurements and confidence intervals provided for all estimates reflect the sampling variability that occurs (1) by chance because only a sample rather than the entire universe is surveyed and (2) by nonresponse.

6.2 Limitations of using extant medical records

Although every effort is made during the data collection phase to collect data accurately and precisely, extant medical records vary in specificity and detail. Factors that may affect the reliability and accuracy of the findings include the following:

• DAWN data collectors attempt to identify with a high degree of specificity the exact drugs involved in an ED visit. If extant medical records include only a general description of a drug (e.g., "benzodiazepines," "narcotic pain reliever"), the drug is grouped in a general category (e.g., benzodiazepines not otherwise specified).
• Many drug-related ED visits involve multiple drugs. In these instances, it may be difficult or impossible to determine whether a single drug is responsible for the visit, or if the visit was the result of the interaction between the drugs. Similarly, when multiple drugs are involved, it should not be assumed that they are all taken for the same reason; a patient may misuse one type of prescription medication while taking another medication as prescribed.
• DAWN seeks to include only the drugs that are related to the ED visit. Any drugs or medications that the patient may be taking regularly are excluded, unless the medical chart indicates that they were implicated in the ED visit. If the ED record is not clear on this point, drugs that were not implicated in the visit may be included in the DAWN data. Conversely, it is also possible that involvement of current medications is underreported if their involvement in the ED visit is not recognized or documented by the clinician.
• DAWN does not produce rates (visits per 100,000 population) for race/ethnicity groups. Information on race and ethnicity is often poorly documented in extant ED records. In addition, some hospitals consider race/ethnicity to be private information and will not make it available to DAWN Reporters. As a result, about 15 percent of visits each year do not contain race/ethnicity information. These missing data result in the systematic understatement of visits by race/ethnicity category.

6.3 Limitations on toxicology test finding

Although DAWN documents whether a drug was positively confirmed by toxicology testing, DAWN does not require that all drugs reported for the ED visit be confirmed by laboratory testing. This is because information about the drugs involved in the ED visit is often available from other sources (for example, the medication may be brought to the ED). Toxicology tests are not used consistently across EDs, and some toxicology tests are not specific enough to identify particular drugs. Furthermore, a positive toxicology test is not necessarily evidence of recent drug involvement in an ED visit if it is a current medication or a drug that persists in the system long after it was used. For this reason, DAWN requires that the involvement of drugs be mentioned in the ED record, not just in the toxicology testing results, for the visit to be considered a DAWN case.

APPENDIX A
HISTORY OF DAWN

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. DAWN was transferred to the U.S. Department of Health and Human Services in 1980. Within Health and Human Services, the National Institute on Drug Abuse conducted DAWN from 1980 to 1992. Since 1992, the Center for Behavioral Health Statistics and Quality (formerly the Office of Applied Studies) of the Substance Abuse and Mental Health Services Administration 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 the National Institute on Drug Abuse 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 contiguous United States and 21 metropolitan areas until 2002. Major population shifts and changes in the hospital industry between 1980 and 2002 made apparent the need for a redesign of the sample of hospitals. Many other features of DAWN (e.g., definition of a DAWN visit to include all drug-related medical emergencies and not merely those involving misuse or abuse) were also redesigned at that time.²¹

In the redesign in 2003, DAWN's goal remained to produce national as well as metropolitan area-level estimates. Retention of the original 21 metropolitan areas was important because of the ongoing demand for DAWN estimates by public health professionals in those areas. In addition, inclusion of major population centers in each of the nine census divisions was deemed important to improve DAWN's geographic and population coverage. A total of 48 metropolitan areas were identified for inclusion in DAWN. The composition of these metropolitan areas was based on the definitions issued by the Office of Management and Budget in June 2003. For consistency, DAWN has maintained the 2003 definitions, even if counties were added in subsequent years.

Between 1980 and 2003, the Office of Management and Budget had substantially enlarged the coverage areas for 4 of the original 21 metropolitan areas. Users of DAWN statistics in these 4 areas—Los Angeles, Miami, New York, and San Francisco—remained interested in obtaining estimates for the areas covered by the original 21 metropolitan areas. To address the needs of these users, DAWN subdivided these metropolitan areas according to their earlier composition and planned oversamples in the subdivided portions. That is, for each of these areas, there was an oversample for the metropolitan area as defined in 2003 and additional oversampling in the submetropolitan areas. When participation is high enough, separate estimates are made for the subdivided areas as well as the entire metropolitan area.

In 2000, DAWN adopted the Multum Lexicon, a drug vocabulary and classification tool developed and maintained by Multum Information Services, Inc., a private firm. Multum distributes the Lexicon and regular updates through its Web site. Multum permits the use of its Lexicon free of charge; a license agreement specifies the terms required of users. In accordance with the license agreement, DAWN publications, tabulations, and software applications cite the Multum Lexicon as the source and basis for the system DAWN uses to code drugs.

The DAWN survey relies on a longitudinal probability sample of hospitals located throughout the United States. To be eligible for selection into the DAWN sample, a hospital must be a non-Federal, short-stay, general surgical and medical hospital located in the United States, with at least one 24-hour ED. This sampling strategy was first implemented in the 2004 data collection year and has been followed since.

APPENDIX B
GLOSSARY OF DAWN TERMS, 2009 UPDATE

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 ingestion of a drug, for example, childhood drug poisonings and individuals who take the wrong medication by mistake. It includes a caregiver administering the wrong medicine by mistake. It does not include a patient taking more medicine than directed because the patient forgot to take it earlier.

Adverse reaction: This category of drug-related ED visits represents the consequences of using a prescription or over-the-counter pharmaceutical for therapeutic purposes and includes visits related to adverse drug reactions, side effects, drug-drug interactions, and drug-alcohol interactions. Although adverse reactions are typically limited to pharmaceuticals, a small number of adverse reaction visits involve illicit drugs (a) for which there are legitimate pharmaceutical versions and (b) pharmaceutical inhalants (such as anesthetic gases).

Alcohol use: DAWN notes whether alcohol was involved in addition to other drug(s) for patients of all ages. Because alcohol is considered an illicit drug for minors, alcohol without the involvement of other drugs is considered a drug-related ED visit for patients under the age of 21. (See Drug misuse or abuse and Underage drinking.)

Case description: A description of how the drug or drugs were related to the patient's ED visit. The case description, in conjunction with other documentation in the ED medical record, is used to determine whether 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 or abuse.

Confidence interval (CI): An interval estimate, that is, a range of values around a point estimate that takes sampling error into account. The accepted standard of confidence is 95 percent. Technically, a 95 percent 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 percent of the time. Practically, a 95 percent CI summarizes both the estimate and its margin of error in a straightforward way with a reasonable degree of confidence.

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

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

Treated and released includes three categories:

• Discharged home—"Home" is used as a broad category to mean the patient's residence. Home is generally used for persons who live locally; however, for students at nearby universities, home means their university; for travelers who get sick on the road, it may mean their hotel or wherever they are staying; and so on.
• Released to police/jail—Patients that are released to police/jail were usually brought to the ED by the police for treatment of an acute medical problem or for medical clearance before being placed in the jail population.
• Referred to detox/treatment—The chart indicates that the patient was referred to a substance abuse treatment or detox program, facility, or provider.

Admitted to this hospital includes five categories of inpatient units:

• intensive or critical care unit,
• surgery,
• chemical dependency/detox unit,
• psychiatric unit, and
• other inpatient units (the inpatient unit was not specified or does not match one of the preceding units).

Other disposition includes five categories:

• Transferred—The patient was transferred to another health care facility.
• Left against medical advice—The patient left the treatment setting without a physician's approval.
• Died—The patient died after arriving in the ED but before being discharged, admitted, or transferred.
• Other—The discharge status is documented in the patient's chart but does not fit into any of the preceding categories.
• Not documented—The patient's discharge status was not documented in the medical chart.

Drug: A substance that is (a) used as a medication or in the preparation of medication; (b) an illicit substance that causes addiction, habituation, or a marked change in consciousness; or (c) both. Substances reportable to DAWN include alcohol, illicit drugs (e.g., club drugs, cocaine, heroin, marijuana, stimulants), nonpharmaceutical inhalants, prescription drugs (e.g., drugs for attention deficit hyperactivity disorder, antibiotics, antidepressants, antipsychotics, anticoagulants, beta blockers, birth control pills, hormone replacement, insulin, muscle relaxants, pain relievers, sleeping aids), drugs used in treatment of medical conditions (e.g., respiratory therapy, chemotherapy, radiation therapy), vaccines, dietary supplements, vitamins, and other over-the-counter pharmaceutical products. DAWN publications use the term "drug" to refer to any of these substances. Multiple substances can be reported for each DAWN case. Therefore, the total number of drugs exceeds the total number of DAWN cases reported.

Drug category: A generic grouping of related pharmaceuticals or other substances reported to DAWN, based on the classification system developed by Multum Information Services, a subsidiary of the Cerner Corporation, and modified for use with DAWN. The Multum Lexicon is available at http://www.multum.com/. In general, the Multum drug categories reflect the therapeutic uses for prescription and over-the-counter pharmaceuticals.

Additional clarification is provided for the following drug categories, because these are unique to DAWN:

• Alcohol alone—DAWN treats alcohol as an illicit drug for minors. Therefore, DAWN collects data on ED visits involving alcohol and no other drugs if the patient is under the age of 21.
• Alcohol-in-combination—DAWN records whether alcohol was involved in all drug-related ED visits for patients of all ages.

Drug misuse or abuse: A group of ED visits defined broadly to include all visits associated with illicit drugs, alcohol use in combination with other drugs, alcohol use alone among those younger than 21 years, and nonmedical use of pharmaceuticals. (See also Alcohol use, Illicit drug use, Nonmedical use of pharmaceuticals, and Underage drinking.)

Drug-related ED visit: This category includes any ED visit related to recent drug use. To be a DAWN case, the ED visit must have involved a drug, either as the direct cause of the visit or as a contributing factor. (See also Single-drug case.) 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.

There are some circumstances in which ED visits are not reviewed for DAWN. These include persons who left before being seen by a physician, visits for suture removal, and direct admission to the hospital through the ED for women in labor.

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 and other adjustments to data from a sample. Estimates of drug-related ED visits are calculated by applying weights and adjustments to the data provided by the sampled hospitals participating in DAWN. The sampling weights reflect the probability of selection; separate adjustment factors account for nonresponse, data quality, and the known total of ED visits delivered by the universe of eligible hospitals as identified by the American Hospital Association (AHA) Annual Survey Database (ASDB) for the relevant time period.

GHB: Gamma hydroxybutyrate, a hallucinogen and depressant frequently combined with alcohol and other beverages. Also used by bodybuilders to aid in fat reduction and muscle building. For further information, see http://www.drugabuse.gov/infofacts/infofactsindex.html.

Hospital emergency department (ED): An emergency department (ED) (also known as an emergency room) is a medical treatment facility, specializing in acute care of patients who present without prior appointment, either by their own means or by ambulance. EDs are usually found in hospitals or other primary care centers. Only EDs in hospitals that meet DAWN's eligibility criteria may participate in DAWN. For information on drug-related ED visits, DAWN relies exclusively on medical records maintained by EDs. No patients, ED staff, or other records are consulted. DAWN is based on a sample of hospitals; in the cases where there are multiple EDs in a hospital, records from all the EDs are reviewed to identify drug-related cases. (See Universe.)

Illicit drug use: This category of drug-related ED visits includes all visits related to the use of illicit or illegal drugs. Illicit drugs include

• cocaine,
• heroin,
• marijuana,
• stimulants (including amphetamines and methamphetamine),
• MDMA,
• GHB,
• flunitrazepam (Rohypnol),
• ketamine,
• LSD,
• PCP,
• other hallucinogens,
• nonpharmaceutical inhalants,
• combinations of illicit drugs, and
• alcohol when used by patients under the age of 21.

Additional clarification is provided for the following drug categories:

• Stimulants—This drug category includes amphetamines, methamphetamine, and other illicit stimulants and excludes central nervous system stimulant medications, such as methylphenidate. Amphetamines and methamphetamine are combined for analysis because medical records and toxicology tests often generically refer to either drug as "amphetamines."
• Amphetamines—Although there are nonillicit (pharmaceutical) amphetamines, the whole of the amphetamine class of substances is grouped with illicit stimulants because it is considered a major substance of abuse. See Illicit drug use for the list of drugs reported individually by DAWN as major substances of abuse.
• Inhalants—This category includes (1) anesthetic gases and (2) any nonpharmaceutical substance that has psychoactive effects when inhaled, sniffed, or snorted. Excluded from the inhalant category are carbon monoxide and nonpharmaceutical inhalants if the exposure was accidental (e.g., inhaling paint fumes while painting a closet).

(1)  Anesthetic gases—Anesthetic gases are presumed to have been inhaled. Included in this category are, for example, nitrous oxide, ether, and chloroform.

(2)  Nonpharmaceuticals—The route of administration for psychoactive nonpharmaceuticals is not assumed and must be documented in ED records specifically as inhalation. Psychoactive nonpharmaceuticals, when inhaled, fall into three main categories: volatile solvents, nitrites, and chlorofluorohydrocarbons. Examples of substances in each of these three categories include the following:

–   Volatile solvents—This category of inhalants includes adhesives (model airplane glue, rubber cement, household glue), aerosols (spray paint, hairspray, air freshener, deodorant, fabric protector), solvents and gases (nail polish remover, paint thinner, correction fluid and thinner, toxic markers, pure toluene, lighter fluid, gasoline, carburetor cleaner, octane booster), cleaning agents (dry cleaning fluid, spot remover, degreaser), food products (vegetable cooking spray; dessert topping spray such as whipped cream or "whippets"), and gases (butane, propane, helium).

–   Nitrites—This category of inhalants includes amyl nitrites ("poppers," "snappers") and butyl nitrites ("rush," "locker room," "bolt," "climax," video head cleaner).

–   Chlorofluorohydrocarbons—Freons are an example of this category of inhalants.

• Combinations not tabulated above (NTA)—This category includes combinations composed of two or more major substances of abuse that are mixed and taken together. For example, "speedball," which usually refers to the combination of heroin and cocaine taken at once, would be classified as a "Combination NTA," whereas heroin and cocaine used separately would be classified separately in the categories heroin and cocaine. Combinations consisting of a major substance of abuse and another substance are classified in the category of the major substance (e.g., heroin with scopolamine is classified as heroin).

LSD: d-lysergic acid diethylamide, a hallucinogen usually taken orally. For further information, see http://www.drugabuse.gov/infofacts/infofactsindex.html.

Malicious poisoning: See Nonmedical use of pharmaceuticals.

MDMA: Methylenedioxymethamphetamine, a hallucinogen with stimulant effects, usually taken orally. For further information, see http://www.drugabuse.gov/infofacts/infofactsindex.html

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 center. Unless otherwise noted, DAWN metropolitan areas correspond to Metropolitan Statistical Areas (MSAs) established by the Office of Management and Budget (OMB) based on the 2000 decennial census and updated in 2003. DAWN also prepares estimates for subsections of three of the large MSAs that correspond to MSA Divisions; in a fourth MSA, subsections were established by local users of DAWN data.

Nonmedical use of pharmaceuticals: Nonmedical use of pharmaceuticals includes taking more than the prescribed dose of a prescription pharmaceutical or more than the recommended dose of an over-the-counter 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 drug, an over-the-counter pharmaceutical, or a dietary supplement. Nonmedical use of pharmaceuticals may involve pharmaceuticals alone or pharmaceuticals in combination with illicit drugs or alcohol. Nonmedical use of pharmaceuticals includes prescription and over-the-counter pharmaceuticals in ED visits that are of the following types of cases:

• Overmedication—Patient took too much of his/her prescription medication or over-the-counter medication/dietary supplement.
• Malicious poisoning—Drug use in which the patient was administered a drug by another person for a malicious purpose (drug-facilitated sexual assault is one type of malicious poisoning, but other types of malicious poisonings, such as product tampering, would be classified in this category as well).
• Case type other—All drug-related ED visits that could not be assigned to any of the other seven types (by design, most cases of documented drug abuse will fall into this category).

(See also Drug misuse or abuse and Type of case.)

Not otherwise specified (NOS): This is the catchall category for substances that are not specifically named but are known to be reportable to DAWN. Terms are classified into an NOS category only when assignment to a more specific category is not possible based on the information in the source documentation (ED patient charts).

Not tabulated above (NTA): This designation is used when drugs or drug categories are not explicitly listed in a table. Low-incidence drugs (or drug categories) falling under a broader drug classification may be summarized into a single row under that classification and labeled as NTA.

Overmedication: See Nonmedical use of pharmaceuticals.

Oversampling: Without oversampling, one would expect a sample to resemble the population from which it was drawn. Oversampling implies the deliberate selection of a much higher proportion of certain types of sampling units than would normally be obtained in a simple, random sample. The deliberate selection of certain types of sample units is done to improve the precision of estimates of the properties of these types of sampling units. This is a form of stratified sampling. (See also Sampling, Sample frame, and Sampling unit.) In DAWN, selected metropolitan areas are oversampled so that estimates can be produced for those areas.

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 0.05, it means that there is no more than a 5 percent probability that the difference observed could be due to chance alone.

PCP: Phencyclidine, a hallucinogenic white crystalline powder that is readily soluble in water or alcohol or may be snorted or smoked. For further information, see http://www.drugabuse.gov/infofacts/infofactsindex.html.

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 percent are regarded as too imprecise to be published. ED table cells where such estimates would have appeared contain the asterisk symbol (*). (See also Relative standard error.)

Race/ethnicity: Race/ethnicity data in DAWN are collected retrospectively from the medical record. This approach involves a single question listing six race/ethnicity groups (plus not documented) and allows for multiple responses.²² For published reports, DAWN collapses the reported race/ethnicity information into four mutually exclusive categories, plus an unknown category, as follows:

• White—A person having origins in any of the original peoples of Europe, the Middle East, or North Africa. Those who are identified as White and Hispanic are classified as Hispanic.
• Black—A person having origins in any of the Black racial groups of Africa. Those who are identified as Black or African American and Hispanic are classified as Hispanic.
• Hispanic—A person of Cuban, Mexican, Puerto Rican, South or Central American, or other Spanish culture or origin, regardless of race. Those who are identified as Hispanic are classified as Hispanic, regardless of any other race/ethnicity designations.
• Race/ethnicity not tabulated above—A person who is an American Indian, Alaska Native, Asian, Native Hawaiian, or Other Pacific Islander, or a person of two or more race/ethnicities.
• Unknown—Race/ethnicity is unknown.

Race/ethnicity is missing from ED patient records about 10 to 20 percent of the time, although this varies widely by hospital. In some cases, the race information is ambiguous (e.g., "European"), and detail about multiple races/ethnicities is often missing. Rates of ED visits per 100,000 are not calculated for race/ethnicity categories because of these data limitations.

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 0.1 and is multiplied by 100 to change it to a percentage. This resulting RSE percent value is 10 percent. The larger the RSE, the less precise the estimate. Estimates with an RSE of 50 percent or greater are not published by DAWN. (See also Precision.)

Sample frame: A list of units from which a sample is drawn. In DAWN, the hospital is the unit used for the ED sample. All members of the sampling frame have a known 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 (ASDB). (See also Universe.)

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 to make inference to all hospitals; DAWN uses simple random sampling within strata.

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 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 reflects 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: An ED visit in which only one drug was involved. The single drug may be the direct cause of the visit or a contributing factor as determined by the medical evaluation done in the ED. Because DAWN considers alcohol to be an illicit drug for minors, DAWN includes visits where alcohol is the single drug if the patient is younger than 21 years of age.

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 (1) two types of hospital ownership (public, private) and (2) up to four size categories (measured in terms of the number of ED visits annually). This allocation creates 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, 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 type of drug-related ED visit captures suicide attempts (e.g., attempted suicide, tried to kill self) that are documented in the medical record and in which a drug was involved. Suicidal gestures, thoughts, or ideation, including attempts to harm oneself, are not included in this category.

Type of case: A classification used to define similar DAWN cases for analysis. Each case must be assigned a type and may not be assigned more than one type. Cases are classified into one of the following eight categories: suicide attempt, seeking detox, alcohol only (age younger than 21), adverse reaction, overmedication, malicious poisoning, accidental ingestion, and other. The case is coded into the first group that meets the inclusion criteria for that group.

Underage drinking: An ED visit where the patient is under age 21 and alcohol is involved. Because DAWN considers alcohol to be an illicit drug for minors, DAWN includes visits where alcohol is the only drug involved and visits where alcohol is present with other drugs.

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 Service are excluded. The universe of EDs is identified from the American Hospital Association (AHA) Annual Survey Database (ASDB).

End Notes

¹ https://dawninfo.samhsa.gov/default.asp.

² Drug-related visits are defined by DAWN as any ED visit related to recent drug use. Additional detail on DAWN's definition of drug-related visits is provided in Section 2.1.

³ https://dawninfo.samhsa.gov/default.asp.

⁴ http://www.icpsr.umich.edu/icpsrweb/SAMHDA/.

⁵ DAWN Reporters are responsible for reviewing ED visit records, deciding if a visit is eligible for DAWN, and, if so, recording select data items for the visit. Additional information on collection of DAWN data is provided in Section 3.2.

⁶ https://dawninfo.samhsa.gov/collect/.

⁷ Alcohol use by a minor with no other drug involvement is eligible for DAWN. Alcohol use by an adult must be accompanied by another drug to be eligible for DAWN.

⁸ To be reportable as an illicit drug, a nonpharmaceutical substance must be intentionally consumed by inhalation, sniffing, or snorting, and it must have a psychoactive effect when inhaled. Carbon monoxide is excluded from the inhalants. Cases involving accidental exposures to inhalants (e.g., exposure to paint fumes while one is painting a closet) are excluded.

⁹ http://dawninfo.samhsa.gov/drug_vocab/.

¹⁰ The redesign of the DAWN ED component is described in detail in DAWN: Development of a New Design, which is available at https://dawninfo.samhsa.gov/pubs/methodology/.

¹¹ The 24-hour status of hospitals is not contained on the AHA file and is determined by contacting otherwise eligible hospitals directly.

¹² Hospitals in the four MSAs with subMSA 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 submetropolitan area, and (3) a POS/stratum for membership in the remainder area.

¹³ In DAWN metropolitan areas, size categories were determined independently for each OS area. The number of hospitals determined the unique size categories: fewer than four hospitals were placed in one size category; four to seven hospitals were placed in two size categories; and eight or more hospitals were placed in four size categories. Areas outside of DAWN metropolitan areas were organized into three size categories.

¹⁴ The ED Reference Guide is available for download from the DAWN Web site, https://dawninfo.samhsa.gov/collect/. The direct link for the document is https://dawninfo.samhsa.gov/files/collect_2009-2011/ed_reference_guide_2009-2011.pdf.

¹⁵ This version of the annual data is referred to as the "microdata" because it includes one record for every brand of drug mentioned in a visit. There are up to 22 records for each visit.

¹⁶ Identical drug IDs can result when different brand codes map to the same drug ID. When the duplicate drug ID is removed, the brand code associated with it will be lost because only one brand is retained for each unique drug ID in the visit-level file. The detailed information on all brands is retained in the brand-level file and can be retrieved if needed.

¹⁷ https://dawninfo.samhsa.gov/pubs/edpubs/.

¹⁸ https://dawninfo.samhsa.gov/pubs/methodology/.

¹⁹ The U.S. Census Bureau issues population estimates for each year between decennial censuses. Each year, the estimates for the current year are issued, and estimates for all years since the decennial are reissued. Each year's estimates are referred to as "Vintage 20xx." DAWN uses the most current vintage estimates.

²⁰ Due to data limitations in 2004, long-term comparisons for ED visits resulting from adverse reactions are made between 2005 and the current year.

²¹ Additional detail on the 2003 redesign is available in the following publication: Substance Abuse and Mental Health Services Administration, Center for Behavioral Health Statistics and Quality. (2002). Drug Abuse Warning Network: Development of a new design (methodology report) (DAWN Series M-4, DHHS Publication No. SMA 02-3754). Rockville, MD: Author.

²² 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).