Validity of self-reported drug use among injection drug users and crack cocaine users recruited through street outreach

Abstract

This paper examines the validity of self-reported drug use as a measure of behavior change for the evaluation of drug use prevention and HIV risk reduction programs. The results of urinalysis are used to evaluate responses from 154 subjects from 4 cities to questions about drug use in the past 48 hours in the National Institute on Drug Abuse's (NIDA) Risk Behavior Assessment (RBA). This instrument is currently being used in 21 studies throughout the United States. Unlike criminal justice or employment settings where there is a tendency to underreport drug use, participants in this research study acted more like a treatment seeking population and were slightly more likely to report drug use than to be tested positive. Urinalysis and self-reports agreed for 86.3% of the subjects who reported use of some form of cocaine (Kappa = .658) and 84.9% of the heroin users (Kappa = .631). The percentage of subjects reporting drug use and testing negative was somewhat higher than the percentage reporting no use and testing positive for both cocaine (7.8% vs. 5.8%) and heroin (9.7% vs. 5.2%). The results suggest that self-reported drug use in not-in-treatment, noninstitutionalized populations is accurate enough for measuring changes in risk behavior practices. Urinalysis may not be necessary if respondents are asked about their drug use in a nonthreatening manner, and if they are assured of the confidentiality of their results.