Background: Among those accessing treatment, highly active antiretroviral therapy (HAART) has transformed HIV into a chronic and manageable condition. However, high levels of adherence are required to derive a sustained, long-term clinical benefit. The aim of this study was to examine the predictors of adherence based on prescription refill among persons on HAART in British Columbia, Canada.
Methods: This study utilizes data collected between July 2007 and January 2010, as part of the Longitudinal Investigations into Supportive and Ancillary health services (LISA) cohort, which is a study of HIV-positive persons who have accessed antiretroviral therapy (ART) in British Columbia. Participants were considered optimally adherent if they were dispensed ≥95% of their prescribed antiretrovirals.
Results: Of a total of 566 participants, only 316 (55.8%) were optimally adherent to HAART. Independent predictors of optimal adherence were increasing age (adjusted odds ratio [AOR] = 1.84, 95% confidence interval [CI]: 1.44-2.33), male gender (AOR = 1.68, 95% CI: 1.07-2.64), and being enrolled in a comprehensive adherence assistance program (AOR = 4.26, 95% CI: 2.12-8.54). Having an annual income <$15 000 (AOR = 0.47, 95% CI: 0.31-0.72) and both former and current injection drug use (AOR = 0.46, 95% CI: 0.29-0.73 and AOR = 0.35, 95% CI: 0.20-0.58, respectively) were independently associated with suboptimal (<95%) adherence.
Conclusions: We found that women and people who inject drugs are at increased risk of being suboptimally adherent to HAART. Optimal adherence remains a significant public health and clinical goal in the context of rapidly expanding access to HAART.