Understanding Factors Influencing HIV pre-exposure prophylaxis adherence among men who have sex with men in Western China: a data-driven exploration using bayesian networks

The efficacy of Pre-exposure prophylaxis (PrEP) is highly dependent on adherence. This study aimed to explore the factors influencing adherence among men who have sex with men (MSM) and their interrelationships, providing theoretical basis for the development of personalized intervention strategies. The data for this study came from a two-phase study of the PrEP demonstration project conducted among MSM in Western China from 2013 to 2023. Participants were given once-daily oral PrEP medication, with tenofovir disoproxil fumarate (TDF) as the primary active ingredient. Follow-up was conducted at the third-month visit after enrollment, during which self-reported adherence and participant characteristics were collected. Adherence greater than or equal to 80% was considered high level. Candidate predictor variables for high adherence were screened by Least absolute shrinkage and selection operator (LASSO) regression and incorporated into the Bayesian network (BN) used to explore the factors and interrelationships of adherence. A total of 11 variables were significantly associated with high adherence through LASSO regression screening. HIV testing, HIV counseling, HIV knowledge score, perceived the threat of HIV, and high-risk sexual behavior were directly associated with high adherence through BN analysis. According to the BN inference, the probability of high adherence among MSM was estimated to increase by 21% (from a baseline of 63% to 84%) after improving these direct influences; meanwhile, the probability of high-risk sexual behavior also increased by 4% (from a baseline of 68% to 72%). The BN approach provided a new perspective for revealing the factors and intrinsic linkages of adherence among MSM. Achieving early monitoring and probabilistic estimation of adherence and related behavioral patterns will facilitate the identification of individuals in need of enhanced intervention and management.