Self-reported and Pharmacologic Adherence During a Demonstration Project on HIV Pre-exposure Prophylaxis among Men who have Sex with Men in Benin

Background and aim. The effectiveness of oral pre-exposure prophylaxis (PrEP) for HIV prevention relies on Adherence. Accordingly, the aim of this study was to compare self-reports that are commonly used in sub-Saharan Africa to monitor adherence with dried blood spots-based results. Materials and methods. The study was part of an oral PrEP demonstration project conducted from August 2020 to December 2021 among 204 men who have sex with other men in Benin. The Mc Nemar test and bivariate log-binomial regression models using the GENMOD procedure were performed to compare adherence levels and explore the association between pharmacologic adherence and four indicators for oral PrEP initiation in Benin. Results. Only 46% and 24.3% of men who provided dried blood spots had detectable drugs levels at month-6 and month-12, respectively. At month-6, perfect adherence for daily PrEP was 92% (self-reports) and 10% (pharmacologic measure; p-value<0.0001) and for event-driven, 49% (self-reports) and 31% (pharmacologic measure; p-value=0.008). At month-12, the corresponding values were 94% and 5% (p<0.0001), and 40% and 27% (p=0.005), respectively. In bivariate analyses, the p-values estimating the association between HIV risk factors and pharmacologic perfect adherence (≥1450 fmol/punch) were 0.173 for consistent condom use, 0.303 for NG and/or CT infections, 0.447 for drug or alcohol consumption, and 0.129 for multiple sexual partnership. Similar results were obtained for partial adherence (≥800 fmol/punch). In post-hoc analyses, three HIV seroconversions were observed in men with a pharmacologic drug concentration <400 fmol/punch. Conclusions. Adherence was generally low and self-reported adherence tended to overestimate pharmacologic adherence. Oral PrEP should be implemented along with continuous adherence support interventions and other HIV prevention tools, including injectable PrEP, so that people can choose the method that adjust the best to their daily life conditions.