Screen of Drug Use: Diagnostic Accuracy of a New Brief Tool for Primary Care

Abstract

Importance: Illicit drug use is prevalent, and primary care provides an ideal setting in which to screen for drug use disorders (DUDs) and negative consequences of drug use (NCDU). Comprehensive reviews have concluded that existing drug use screening instruments are not appropriate for routine use in primary care.

Objective: To develop and validate a screening instrument for drug use.

Design, setting, and participants: We revised items drawn from existing screening instruments and conducted signal detection analyses to develop the new instrument. We approached 3173 patients at 2 primary care clinics in a US Department of Veterans Affairs health care system from February 1, 2012, through April 30, 2014. A total of 1300 (41.0%) patients consented to the study, of whom 1283 adults were eligible (mean [SD] age, 62.2 [12.6] years). In the last 12 months, 241 (18.8%) participants reported using illicit drugs or prescription medication for a nonmedical purpose, and 189 (14.7%) reported 1 or more NCDU. A total of 133 (10.4%) patients met DSM-IV criteria for a DUD. The sample was randomly divided first to develop the measure and then to validate it.

Main outcomes and measures: The Mini-International Diagnostic Interview was used as the criterion for DUDs, and the Inventory of Drug Use Consequences was used as the criterion for NCDU.

Results: The screening instrument has 2 questions. The first is, "How many days in the past 12 months have you used drugs other than alcohol?" Patients meet that criterion with a response of 7 or more days. The second question asks, "How many days in the past 12 months have you used drugs more than you meant to?" A response of 2 or more days meets that criterion. The screening instrument was 100% sensitive and 93.73% specific for DUDs (643 patients); when replicated in the second half of the sample (640 patients), it was 92.31% sensitive and 92.87% specific. The screening instrument was 93.18% sensitive and 96.03% specific for NCDU (643 patients); when replicated in the second half of the sample (640 patients), it was 83.17% sensitive and 96.85% specific.

Conclusions and relevance: The 2-item screen of drug use has excellent statistical properties and is a brief screening instrument for DUDs and problems suitable for busy US Department of Veterans Affairs primary care clinics.