The public health response to the HIV/AIDS epidemic has turned its focus on means of optimizing health care delivery, and re-engineering delivery systems to maximize case identification, as well as access and sustained engagement in antiretroviral treatment. Opioid Substitution Treatment (OST) provides a critical opportunity for HIV testing and linkage to antiretroviral treatment. The EHOST study is a cluster-randomized, stepped-wedge trial to evaluate a prescriber-focused intervention to increase HIV testing rates, and optimize antiretroviral treatment re-engagement and retention outcomes among individuals engaged in OST. The study will encompass all drug treatment clinics currently admitting patients for the treatment of opioid dependence across the province of British Columbia, which are thought to treat 90% of the OST caseload. The trial will be executed over a 24-month period, with groups of clinics receiving the intervention in 6-month intervals. Evaluation of the effectiveness of the proposed intervention will be conducted entirely through existing data collection mechanisms, and focuses on three primary outcomes: (i) the HIV testing rate among those not known to be HIV positive; (ii) the rate of Highly Active Antiretroviral (HAART) initiation among those not on HAART; and (iii) the rate of HAART continuation among those on HAART. Despite the randomized delivery of the intervention, a difference-in-differences analytical framework will be applied to adjust for potential residual heterogeneity in patient case mix, volume, and quality of care across OST clinics. Facilitated by established collaborations between key stakeholders across the province, we hypothesize that the EHOST intervention will optimize HIV testing and care within this marginalized and hard-to-reach population.
