Brief Report: Intersecting Vulnerabilities: The Role of Housing Instability and Methamphetamine Use on HIV Acquisition

BACKGROUND: This study examines the synergistic impact of housing instability and methamphetamine use on the incidence of HIV infection. SETTING: Data are from a prospective cohort study of men who have sex with men in Los Angeles, CA. Participants were recruited from a university-based research clinic and a community sexual health/HIV clinic, where both recruitment and study activities were conducted. METHODS: Eligible participants were 18-45 years of age, male, reported HIV transmission-potential sexual behaviors, and tested HIV-negative at baseline. At semiannual visits, participants reported housing status and substance use and underwent HIV testing. Unstable housing was defined as ≥1 day without a regular place to stay. Methamphetamine use (past 6 months) was reported as daily, weekly, monthly, less often, or never. Survival analysis with time varying covariates assessed incidence and factors associated with HIV seroconversion. RESULTS: This analysis included 277 participants enrolled between 2014 and 2022 with ≥1 follow-up visit through January 2025 [n = 2453 study visits; median follow-up 4.6 years (IQR: 1.1-7.6)]. Past 6-month methamphetamine use was 32%, and unstable housing was 34%. Twenty one participants tested positive for HIV at follow-up [incidence 1.6/100 person-years (PY), highest among those with unstable housing and daily methamphetamine use (7.7/100 PY)]. Daily methamphetamine use and unstable housing were both associated with HIV seroconversion (HR = 3.1, 95% CI: 1.1 to 8.6; HR = 2.1, 95% CI: 0.9 to 5.3, respectively). CONCLUSIONS: These findings demonstrate the potential synergy between housing instability and daily methamphetamine use on HIV risk and underscore the need for integrated prevention strategies that address these factors.