Associations Between PrEP Stigma, PrEP Confidence, and PrEP Adherence: Conditional Indirect Effects of Anticipated HIV Stigma

Background: Research has linked stigma surrounding preexposure prophylaxis (PrEP) to poor HIV prevention outcomes, including PrEP adherence. However, there remains a limited understanding of the mechanisms through which PrEP stigma affects PrEP adherence, specifically among sexual and gender minority (SGM) youth. In this study, we aimed to investigate the indirect effect of PrEP stigma on PrEP adherence through PrEP confidence and the moderating role of anticipated HIV stigma. Methods: Participants included 235 SGM youth, assigned male sex at birth, aged 16–24, and self-reported HIV-negative, with an active PrEP prescription from the Prepared, Protected, emPowered randomized controlled trial. Participants were recruited from 9 clinics in the United States between 2019 and 2021. Using baseline data, we tested cross-sectional indirect and conditional indirect effects using the Statistical Package for the Social Sciences Process with confidence intervals and 2000 resamples. Results: We found significant indirect effects, suggesting that PrEP stigma was negatively associated with PrEP confidence, which in turn resulted in both monthly and weekly optimal PrEP adherence (Indirect effects: B = −0.11, Standard Error [SE] = 0.05, CI: [−0.244 to −0.032]; B = −0.09, SE = 0.04, CI: [−0.191 to −0.014], respectively). Anticipated HIV stigma moderated these indirect effects (B = −0.11, SE = 0.08, CI: [−0.315 to −0.001]; B = −0.09, SE = 0.06, CI: [−0.245 to −0.001], respectively), suggesting that the conditional indirect effects were significant at high but not low levels of anticipated HIV stigma. Conclusion: Results suggest that SGM youth who are on PrEP anticipating HIV stigma experience a compounding effect of PrEP stigma on PrEP confidence, consequently leading to suboptimal adherence. Interventions addressing the intersectionality of PrEP and HIV stigmas and enhancing confidence could improve PrEP adherence, particularly among SGM youth.