Adherence to pre-exposure prophylaxis among men who have sex with men: A prospective cohort study

To evaluate adherence to pre-exposure prophylaxis (PrEP) in a clinical trial of a population of men who have sex with men (MSM), to explore the influence of social psychology and objective factors (e.g., forgetting, too busy) on adherence, and to provide evidence for subsequent PrEP research.

This study analyzed the data from the daily medication group within a PrEP study (a randomized placebo-controlled trial of oral tenofovir among MSM in Western China from April 2013 to March 2015). A total of 331 participants were analyzed. PrEP adherence was self-reported by the subjects at every 3-month follow-up visit for 24 months. AIDS-related information including HIV prevention, transmission, and treatment knowledge, as well as PrEP-related motivation (including personal and social motivation) and behavior skills, i.e., self-efficacy, were collected using questionnaires. The objective reasons for non-adherence were collected during face-to-face follow-up visits every 3 months. A theoretical model of information motivation behavior skills (IMB) was constructed. Then confirmatory factor analysis was performed to test the fit of each IMB construct. Finally, the structure equation model was used to evaluate the IMB model.

The median adherence rate was 64.29%. During the follow-up period, the percentage of high adherence (adherence ≥80%) was 32.33%, intermediate adherence (adherence 40-80%) was 38.97%, and low adherence (adherence ≤40%) was 28.70%. The final IMB model showed that there was no significant correlation between adherence to PrEP and the psychological constructs: information, motivation, and behavior skills. The main objective reasons for non-adherence were 'forgetting to take medicine' (70.21%), 'too busy' (29.08%), 'worrying about side effects' (28.01%), and 'too much trouble' (18.44%).

This study found no association between PrEP adherence and social psychological factors, and the main objective factor in non-adherence was forgetting to take the medicine. In the future, the MSM population could be reminded to take their medicine regularly using electronic devices, which may improve PrEP adherence to some extent and may further reduce the incidence of HIV. The strategy to improve PrEP adherence requires further study.