Effectiveness of PrEP Uptake and Adherence Interventions for Gay, Bisexual, and Other Men Who Have Sex with Men (MSM): A Systematic Review

Purpose: Each year, almost 39,000 people in the US are diagnosed with HIV and 69% are MSM (CDC, 2020). PrEP, a highly efficacious once-a-day pill to prevent HIV, was FDA-approved in 2012. However, limited PrEP uptake and suboptimal adherence are well-documented. Despite almost a decade of PrEP implementation, to date, no systematic review has been conducted to assess effectiveness and methodological rigor of behavioral intervention studies. Thus, this review addressed the following research questions: 1) what types of interventions were utilized to improve PrEP uptake and adherence for MSM, 2) what were the common outcomes assessed across studies, 3) what were the methodological strengths and weaknesses of the intervention studies, and 4) what interventions were most effective when considering the rigor of the study’s methods?

Methods: A systematic search of 9 databases was conducted to identify studies that evaluated interventions to improve PrEP uptake and adherence among MSM. Inclusion criteria were the following: 1) published in peer-reviewed journals between 2012 and 2021, 2) sample that was >50% MSM, 3) individual-level outcomes for PrEP uptake and/or adherence, 4) conducted in the US. Methodological rigor was assessed using an adapted version of the 12-item Methodological Quality Rating Scale (MQRS). The mean of the total scale scores (possible range 0-14) was used to identify higher and lower rigor studies, and to assess methodological strengths and weaknesses. Methodological rigor was combined with statistical significance to assess the evidence of effectiveness for the most common study outcomes. Strong evidence included studies that reported significant effects with high rigor, promising interventions reported nonsignificant effects with high rigor, and weak evidence included studies that reported nonsignificant effects with low or high rigor or did not report significance. Outcomes were compared by intervention type.

Results: Seventeen studies met inclusion criteria. Intervention types included counseling (n = 5), education and resources (n = 6), and peer-based interventions (n = 6). Common outcomes across studies included PrEP uptake (n = 14) and PrEP adherence (n = 5). Methodological rigor across studies ranged from 4 to 13 (M=7.71, SD =2.37) and 50% scored below the mean. Methodological strengths included transparent reporting of attrition and generalizability. Methodological weaknesses included a lack of objective verification of PrEP use, study designs without randomization, and a lack of statistical power to detect between group differences.

Out of 14 studies with PrEP uptake outcomes, two studies (14%) provided strong evidence of effectiveness for increasing PrEP uptake, one study provided promising evidence (7%), while 11 studies (79%) provided weak evidence. Out of 5 studies with adherence outcomes, two studies (40%) provided strong evidence of effectiveness for increasing PrEP adherence, and three studies (60%) provided weak evidence. The strength of the evidence by intervention type was inconclusive.

Conclusions and Implications: Findings suggest that only two interventions showed strong evidence to increase PrEP uptake and two interventions showed strong evidence to increase PrEP adherence. Future research using study designs with comparison groups are needed to deepen our knowledge of what types of PrEP interventions are most effective for MSM.