Methamphetamine Use and HIV Risk Behaviors in a Cohort of Homeless-Experienced Adults Who Use Drugs.

Methamphetamine use has increased substantially in the United States, particularly among people experiencing homelessness. While the association between methamphetamine use and HIV risk has been studied in other populations, its impact on HIV risk behaviors among people experiencing homelessness remains less well-studied. The objective of this study was to evaluate the relationship between methamphetamine use and HIV risk behaviors in a cohort of people experiencing homelessness who use drugs. We conducted a cross-sectional survey of adults with recent drug use recruited from three homeless-serving clinical sites in Boston, Massachusetts, between February 2024 and January 2025. The primary exposure was past 3-month methamphetamine use (any vs. none). The primary outcome was a composite measure of HIV risk behavior in the past 3 months, categorized as low (0 events), moderate (1-11 events), or high (≥ 12 events), based on self-reported condomless sex and shared needle events. Secondary outcomes included sex-related and injection-related HIV risk behaviors, examined separately. We used multinomial logistic regression to assess associations with overall and sex-related HIV risk behaviors, and bivariate analyses for injection-related HIV risk behavior due to sparse outcome data. Of 196 participants, the mean age was 48 years. 60% identified as cis-gender male, 56% as White, 31% as Black, and 20% as Hispanic. Methamphetamine use in the past 3 months was reported by 42% of participants. Its use was not independently associated with overall HIV risk behavior (aRR for high vs. low risk: 2.20; 95% CI: 0.84-5.77) or sex-related HIV risk behavior (aRR for high vs. low risk: 1.45; 95% CI: 0.53-4.00). However, in bivariate analyses, methamphetamine use was significantly associated with injection-related HIV risk behaviors: individuals who used methamphetamine were less likely to have low-risk behavior (27% vs. 79%) and more likely to have moderate-risk (43% vs. 8%) and high-risk (31% vs. 4%) behaviors (P < 0.001). Among homeless-experienced adults who use drugs, methamphetamine use was associated with higher-risk injection behaviors but not with sex-related HIV risk behaviors. HIV prevention strategies in this population should prioritize safer injection practices, evidence-based methamphetamine treatment, and equitable access to pre-exposure prophylaxis.