Ongoing drug use and outcomes from highly active antiretroviral therapy among injection drug users in a Canadian setting.

BACKGROUND The effect of ongoing illicit drug use on HIV treatment remains controversial, especially in countries where access to HIV treatment for active injection drug users (IDUs) is limited because of presumed non-adherence. We sought to investigate the influence of drug use patterns on adherence to antiretroviral therapy and virological suppression among IDUs. METHODS Using generalized estimating equation logistic regression, we explored the effect of abstinence versus ongoing drug use on adherence and virological suppression using data from a community-recruited cohort of IDUs in Vancouver (BC, Canada). RESULTS A total of 381 HIV-positive IDUs were included in this analysis, among whom the median follow-up time was 30 months. In a multivariate model, no relationship was found between abstinence (reference) and active injection (adjusted odds ratio [AOR] 0.88, 95% confidence interval [CI] 0.65-1.17) and non-injection (AOR 0.97, 95% CI 0.67-1.41) drug use with adherence. In subanalyses, ongoing injection drug use was associated with a lower odds of virological suppression in comparison to abstinence (AOR 0.74, 95% CI 0.57-0.97; P=0.026) and both active IDUs and active non-IDUs had lower odds of virological suppression compared with abstinent participants when longer periods of virological suppression were considered. CONCLUSIONS Given the absence of a strong relationship between abstinence and ongoing drug use and adherence among HIV-positive IDUs, programmes that restrict antiretrovirals to abstinent individuals should be re-examined. The lower rates of virological suppression associated with ongoing drug use nevertheless highlight the importance of comprehensive systems of care and addiction treatment for active drug users.