PrEP Use Likelihood Among People Who Use Opioid Drugs: Understanding Clinical Correlates Along the Opioid Use Disorder Treatment Cascade.

People with opioid use disorder (PWOUD) are at high risk of HIV infection, yet uptake of PrEP remains low in PWOUD. To understand opportunities to increase PrEP engagement, this cross-sectional study sought to examine clinical correlates of perceived PrEP use likelihood in a sample of PWOUD along the OUD Treatment Cascade. We enrolled 120 PWOUD with past-6-month injection drug use (IDU) or condomless sex in a cross-sectional survey study. Participants were recruited from sites serving PWOUD in the Boston area, including substance use disorder (SUD) treatment programs and harm reduction service providers. PWOUD characterized their substance use and treatment history, perceived risk of acquiring HIV, and likelihood of using oral and long-acting injectable (LAI) PrEP. Ordinal logistic regression and Pearson correlations were used to examine correlates of likelihood of using oral and LAI-PrEP. Contrary to hypotheses, current MOUD engagement was not associated with perceived likelihood of using oral or LAI-PrEP. More recent IDU was associated with greater likelihood of using both oral PrEP (OR = 0.98, 95% CI: 0.97, 0.99) and LAI-PrEP (OR = 0.99, 95% CI: 0.98, 1.00). PWOUD who received past-year emergency department-based SUD treatment endorsed lower likelihood of using LAI-PrEP (OR = 0.40, 95% CI: 0.19, 0.84). Among PWOUD, a greater number of sex partners was a stronger correlate of perceived risk of acquiring HIV than IDU-related risk behaviors. Results suggest opportunities to engage PWOUD at greatest HIV risk in PrEP care; findings also suggest need for education interventions to inform judgments of HIV risk among PWOUD.