Monitoring drug use among HIV/AIDS patients in Brazil: should we combine self-report and urinalysis?

Illicit drug use in HIV-infected patients can be linked to impairment of physical and mental health, low health related quality of life, and suboptimal adherence to HIV treatment. This study aimed to evaluate the correlation of self report illicit drug use, urinalysis for cocaine and cannabis metabolites, and severity of dependence among HIV-infected patients on antiretroviral therapy (ART) in a treatment center in Brazil. Four hundred and thirty-eight outpatients of an HIV referral center were interviewed and assessed for drug use (lifetime, last year and last month). Urinalysis was performed to detect the presence of cocaine and cannabis metabolites in urine samples. Overall agreement between self report and urinalysis was almost 68% for cannabis and higher than 85% for cocaine. Positive urinalysis was significantly associated with more than once a week cannabis (p< .0001) and cocaine (p< .0001) use during the last-month. Severity of Dependence Scale (SDS) properly predicted positive cocaine urinalysis results (area under the curve [AUC] = .81, p = .0001). Frequency of cannabis and cocaine use, SDS score degree and positive urinalysis for both drugs were correlated. Our findings suggest that positive self-report is a reliable predictor of positive urine sample both for cannabis and cocaine, but since the agreement was not perfect, there is a role for urine drug screening in the care of patients with HIV-related conditions.