Alcohol and drug use, partner PrEP use and STI prevalence among people with HIV.

Objectives People with HIV (PWH) have a high burden of bacterial sexually transmitted infections (STIs). We examined the relationship of alcohol and drug use and partner pre-exposure prophylaxis (PrEP) use to STI prevalence in a cohort of PWH with a history of unhealthy alcohol use. Methods We analysed data from a primary care-based alcohol intervention study at Kaiser Permanente Northern California (KPNC). Participants were recruited between April 2013 and May 2015 and were followed for up to 24 months. We linked participant responses to questions from the 24 month follow-up interview, including alcohol and drug use and partner PrEP use, with STI test results (ie, syphilis, chlamydia, gonorrhoea) in the KPNC electronic health record. Prevalence ratios (PR) were estimated using Poisson models fitted with robust variance estimators to evaluate the association of substance use and partner use of PrEP with STIs. Results In the analytic sample (n=465), the median age was 52 years (IQR 45-59); 67% were white; 95% were men who have sex with men. Thirty-two per cent of participants had HIV-positive partners only; 31% had HIV-negative partners with at least one on PrEP in the previous year and 37% had HIV-negative partners without any on PrEP. Twenty-three per cent reported alcohol and drug use prior to sex in the last 6 months. Eight per cent of participants had an STI. Partner PrEP use (adjusted PR (aPR) 2.99 (95% CI 1.11 to 8.08)) was independently associated with higher STI prevalence. Participants who reported use of alcohol (aPR 1.53 (0.61 to 3.83)), drugs (aPR 1.97 (0.71 to 5.51)) or both (aPR 1.93 (0.75 to 4.97)) prior to sex had a higher STI prevalence. Conclusions The higher prevalence of STIs among PWH with unhealthy alcohol use who have partners on PrEP suggests that this subgroup may be a high-yield focus for targeted outreach, STI screening and sexual health counselling.