Factors Influencing Oral Pre-, Post-, and Doxycycline Post-Exposure Prophylaxis Uptake Among Substance-Using Men Who Have Sex with Men in the Rural Southern US.

Substance-using men who have sex with men (MSM), especially those in rural areas, face a heightened risk of HIV and sexually transmitted infections (STIs). Despite increased risk, uptake of HIV pre-exposure prophylaxis (PrEP), HIV post-exposure prophylaxis (PEP), and doxycycline post-exposure prophylaxis (Doxy-PEP) remains low among rural MSM. The multi-domain factors influencing past-year use of oral PrEP, PEP, and Doxy-PEP among substance-using MSM in the rural southern US remain unknown. A cross-sectional study of rural substance-using MSM (n = 345) in the Southern US was conducted from February 29 to March 23, 2024. Three series of bivariate and multivariate logistic regression analyses were conducted. Past-year PrEP use was significantly associated with HIV-negative status (adjusted odds ratio [aOR] = 2.55, 95% confidence interval [CI]: 1.12-5.80, p = 0.025), past-year STI diagnosis (aOR = 2.23, 95% CI: 1.19-4.15, p = 0.012), past-year HIV testing (aOR = 3.40, 95% CI: 1.05-10.9, p = 0.040), and past-year STI testing (aOR = 10.09, 95% CI: 2.25-45.37, p = 0.003). Past-year PEP use was significantly associated with past-year STI diagnosis (aOR = 3.70, 95% CI: 1.33-10.32, p = 0.012) and oral sex (aOR = 0.09, 95% CI: 0.01-0.63, p = 0.015). Finally, past-year Doxy-PEP use was significantly associated with past year-STI diagnosis (aOR = 4.44, 95% CI: 2.03-9.71, p < 0.001). Results underscore the need for integrated care across primary care, pharmacy, and substance use treatment settings to improve screening, education, and prescription of HIV/STI preventative biomedical pharmaceuticals for substance-using MSM.