(PS8-45) Factors Associated with Pre-exposure Prophylaxis Self-efficacy and Self-reported Adherence Among a Sample of Men Who Have Sex with Men

Self-efficacy, one’s confidence in their ability to engage in a particular behavior, is a consistent and important individual level variable associated with health behavior, and may be particularly relevant to pre-exposure prophylaxis (PrEP) in men who have sex with men. Few studies, however, have looked at predictors of PrEP self-efficacy among sexual minority men (SMM) in the United States, a priority group as part of the Ending the Epidemic initiative. This study investigates, using cutting-edge methods for variable selection, potential predictors of PrEP self-efficacy, and in turn, PrEP adherence in a sample of SMM.

SMM (N=241) with a current daily oral PrEP prescription were recruited to participate in a randomized control trial to test the efficacy of a PrEP adherence intervention. Data are from the baseline assessment, which includes sociodemographics, and potential psychosocial and structural factors (e.g., immigration status, incarceration, cost of medication, insurance). Data on self-reported PrEP adherence (daily versus less than daily) and PrEP self-efficacy were also collected. Stochastic search variable selection (SSVS), a Bayesian technique for systematically identifying relevant variables, was used to identify potential sociodemographic, psychosocial and structural factors that might influence PrEP self-efficacy and self-reported PrEP adherence. Multiple linear and logistic regression models were then constructed to explore independent associations.

SSVS identified age, U.S nativity, positive attitudes about PrEP, and structural barriers as potential predictors of PrEP self-efficacy. In a multivariable linear regression model, older age (b = 0.05, CI: 0.003,0.09, p = 0.04), being born in the U.S. (b = 2.11, CI = 0.93, 3.30, p = < 0.001), and positive attitudes about PrEP (b = 0.69, CI = 0.50, 0.89, p = < 0.001) were associated with increased PrEP self-efficacy, while facing structural barriers was linked to decreased PrEP self-efficacy (b =- 0.31, CI= -0.43, -0.20, p = < 0.001). For self-reported adherence, SVSS identified PrEP self-efficacy (scale ranged from 0 to 32), and positive attitudes about PrEP (scale ranged from 0 to 20) as potential predictors. In the multivariable logistic regression model, each one-unit increase in PrEP self-efficacy increased the odds of daily self-reported adherence by 12% (OR= 1.12, CI: 1.04, 1.20, p=.002), and for each one-unit increase in positive attitudes about PrEP, the increase was 25% (OR= 1.25, CI: 1.10, 1.43, p = < .001).

The study highlights the impact of both individual factors (e.g. positive attitudes about PrEP, age, and U.S. nativity) and structural barriers (e.g. PrEP cost, insurance, transportation) on one’s confidence in their ability to take PrEP as prescribed (self-efficacy) among SMM. Cognitive-behavioral interventions, particularly those addressing adherence, should focus on addressing modifiable targets such as PrEP attitudes and prioritize incorporating problem solving strategies to address challenges associated with SMM’s lower confidence to take PrEP as prescribed. Ideally, such interventions would co-occur with initiatives that address structural barriers, and/or include specific content that helps individuals overcome such barriers.