Measurement of Current Substance Use in a Cohort of HIV-infected Persons in Continuity HIV Care, 2007-2015

Abstract

Accurate, routine measurement of recent illicit substance use is challenging. The Johns Hopkins Human Immunodeficiency Virus Clinical Cohort (Baltimore, MD) collects two imperfect but routine measurements of recent substance use: medical record review and self-interview. We used Bayesian latent class modeling to estimate sensitivity and specificity of each measurement, and prevalence of substance use among 2,064 patients engaged in care from 2007 to 2015. Sensitivity of medical record review was higher than sensitivity of self-interview for cocaine and heroin use; posterior estimates ranged from 44% to 76% for cocaine use and from 39% to 67% for heroin use, depending on model assumptions and priors. In contrast, sensitivity of self-interview was higher than sensitivity of medical record review for any alcohol use, hazardous alcohol use, and cigarette smoking. Posterior estimates of sensitivity of self-interview were generally above 80%, 85% and 87% for each substance, respectively. Specificity was high for all measurements. From one model, we estimated prevalence of substance use in the cohort to be 12.5% for cocaine; 9.3% for heroin; 48.5% for alcohol; 21.4% for hazardous alcohol; and 55.4% for cigarettes. Prevalence estimates from other models were generally comparable. Measurement error of substance use is non-trivial and should be accounted for in subsequent analyses.