A Group-Based Trajectory Model for Changes in Pre-Exposure Prophylaxis and Condom Use Among Men Who Have Sex with Men Participating in the ANRS IPERGAY Trial

Pre-exposure prophylaxis (PrEP) is one of the most important milestones in HIV prevention for high-risk HIV-negative people. The introduction of PrEP into the HIV prevention package has raised the question of possible risk compensation, and in particular, a reduction in condom use. Although open-label extension (OLE) studies have enabled investigators to examine risk compensation in more real-life settings, results to date have been inconclusive regarding PrEP-induced behavioral changes. We aimed to identify behavioral trajectories over time for PrEP and condom use, and to investigate the link between these trajectories. Group-based trajectory modeling using logistic specification was implemented. Data of the 332 individuals participating in the double-blind and OLE phases of ANRS IPERGAY were used. Four distinct group trajectories were identified: 49.7% of the participants had ``systematic adherence to PrEP,'' 19% had ``high adherence to PrEP, 15.3% had ``declining adherence to PrEP,'' and 16% had ``low adherence to PrEP.'' Two condom trajectories were identified: 53% (n = 176) of the 332 participants were ``low-level users'' of condoms, and 47% were ``high-level users.'' Among the former, 24.4% also belonged to the ``low adherence to PrEP'' group. This most-at-risk group represented 13% of all the participants. The effectiveness of offering sexual activity-based PrEP as part of the French HIV prevention package in the ANRS IPERGAY clinical trial is demonstrated by the relatively small proportion of participants that offset their low-level condom use with PrEP adherence. The results from this work may help in the future development of tailored prevention programs for high-risk HIV-negative people