Prevalence and Correlates of Reporting Difficulty Taking Antiretroviral Treatment Among HIV-Positive Illicit Drug Users in Vancouver, Canada: A Longitudinal Analysis

People living with HIV who use illicit drugs continue to experience high rates of suboptimal treatment outcomes from antiretroviral therapy (ART). Although previous studies have identified important behavioural, social and structural barriers to ART adherence, the effects of patient-level factors have not been fully evaluated. Thus, we sought to investigate the prevalence and correlates of reporting ART was difficult to take among a cohort of illicit drug users in Vancouver, Canada. We accessed data from the AIDS Care Cohort to evaluate Exposure to Survival Services (ACCESS), an ongoing prospective cohort of HIV-positive illicit drug users linked to comprehensive HIV clinical monitoring records. We used generalized linear mixed-effects modeling to identify factors longitudinally associated with periods in which individuals reported they found ART difficult to take. Between December 2005 and May 2014, 746 ART-exposed illicit drug users were recruited and contributed at least one study interview. Finding ART hard to take was reported by 209 (28.0%) participants at baseline, and 460 (61.7%) participants throughout the study period. Patients ingesting a greater daily pill count (adjusted odds ratio [AOR]=1.12 per pill, 95% confidence interval [CI] 1.08-1.17) and experiencing barriers to healthcare (AOR=1.64, 95% CI 1.34-2.01) were more likely to report difficulty taking ART. Patients less likely to report satisfaction with their HIV physician (AOR=0.76, 95% CI 0.58-1.00) and achieve a non-detectable HIV viral load (AOR=0.62, 95% CI 0.51-0.74) were more likely to report finding ART hard to take. In this community-recruited cohort of ART-exposed illicit drug users, a substantial proportion reported they found HIV treatment hard to take, which was clearly linked to higher dissatisfaction with healthcare experiences and, most importantly, a lower likelihood of experiencing optimal virologic outcomes. Our findings reveal a number of opportunities to improve HIV treatment experiences and outcomes for people who use illicit drugs, including the use of treatment regimens with lower pill burdens, as well as reducing barriers to healthcare access.