Determinants of HIV Preexposure Prophylaxis Adherence among Female Sex Workers in a Demonstration Study in Cotonou, Benin: A Study of Behavioral and Demographic Factors

Background HIV preexposure prophylaxis (PrEP) efficacy is closely linked to adherence, and factors associated with PrEP adherence are not well understood and may differ across populations. As PrEP demonstration projects and implementation are ongoing, it is essential to understand factors associated with adherence to oral PrEP to design effective adherence interventions and maximize the public health impact of PrEP. We thus aimed to assess demographic and behavioral factors associated with optimal PrEP adherence (100%) among female sex workers (FSWs) participating in a demonstration project in Cotonou, Benin. Methods Female sex workers were provided with daily Truvada and followed quarterly for 1 to 2 years. Sociodemographics, partners, and behaviors were collected through face-to-face questionnaires. Another questionnaire based on sexual the theory of planned behavior and the theory of interpersonal behavior was also administered. Generalized estimating equations were used to identify factors associated with optimal daily adherence. Results At baseline, 255 FSWs were followed up. One-year increase in age of FSWs was associated with a 3% increase in optimal adherence (prevalence ratio, 1.03; 95% confidence interval, 1.01-1.05; P for trend = 0.0003), and optimal adherence decreased by 31% for every 6 months of follow-up (prevalence ratio, 0.69; 95% confidence interval, 0.59-0.79; P for trend < 0.0001). For the participants who have completed the behavioral questionnaires, high intention to adhere to the treatment was also a predictor of optimal adherence. Conclusions Efforts should be geared toward FSWs intending to use PrEP to help them reach adequate adherence levels for effective HIV protection.