Psychosocial factors in adherence to antiretroviral therapy among HIV-positive people who use drugs.

Objective: Suboptimal adherence to antiretroviral therapy (ART) among HIV-infected people who use illicit drugs (PWUD) remains a significant concern, and there is a lack of effective adherence interventions for this population. Therefore, we sought to identify psychosocial determinants of optimal adherence, including adherence self-efficacy and outcome expectancies, with the aim of informing interventions designed to improve adherence among PWUD.

Methods: From December 2005 to November 2013, we collected data from the AIDS Care Cohort to evaluate Exposure to Survival Services (ACCESS), a prospective cohort of PWUD in Vancouver, Canada. We used multivariable generalized estimating equations (GEE) analysis to identify longitudinal factors independently associated with 95% or greater adherence to ART.

Results: Among 667 participants, including 220 (33%) women, 391 (59%) had 95% or greater ART adherence at baseline. In multivariable GEE analysis, adherence self-efficacy, adjusted odds ratio (AOR) = 1.16, 95% confidence interval (CI) [1.11, 1.21] per 10-point increase, was independently and positively associated with adherence, while negative outcome expectancy, AOR = 0.95, 95% CI [0.93, 0.98], was negatively associated.

Conclusions: In light of the ongoing challenges associated with ART adherence among HIV-positive PWUD, and our findings of associations between adherence, self-efficacy, and outcomes expectancies, tailored intervention strategies based on constructs of social learning theory should be implemented and evaluated to improve adherence among HIV-infected PWUD.