Barriers and Facilitators of Adherence in User-Dependent HIV Prevention Trials, a Systematic Review

Background: Suboptimal adherence to investigational products has been associated with ineffectual outcomes in clinical trials. This review provides a summary of factors that influenced adherence in HIV prevention trials.

Method: Our search included user-dependent trials that focused on sexual transmission of HIV. MEDLINE, Cochrane CENTRAL, Web of Knowledge v5.6, and Clinicaltrials.gov databases were searched as of August, 2012 and HIV/AIDS conference abstracts, March 2013.

Results: Twenty four HIV prevention trials were included. Main barriers related to adherence included; pregnancies, mobility and relocation from study area, adherence declining overtime as a result of fatigue, stigma and negative rumors about the clinical trials, and gel volume to be inserted perceived as too much. Other reported barriers were side effects, alcohol use, running out of study product after missing clinic visits, pill/gel sharing, forgetting to take/use study product, unplanned sex (in studies with coital-dependent dosing), concealing trial participation from partner, difficulty in sustaining high adherence levels in study products with a short half-life of 1-3 hours, and simultaneous use of multiple products. Key facilitators of adherence included; male involvement in trial related activities or disclosure of study participation to male partner, product acceptability, older age (>25 years), and high risk perception of HIV. Other facilitators were; routinizing pill taking, perceived enhancement of male partner’s sexual pleasure, adequate supply of study product, good staff-participant relationship, less education, unannounced adherence support visits, and no overt side effects experienced as reported by participants.

Conclusion: Information on investigational prevention products should be packaged and delivered in ways that appeal to realities of participants’ lives while remaining scientifically factual. Trials should customize adherence messages to address difficulties with study product use and prioritize community engagement to respond to issues around stigma, rumors and potential partner concerns. Additionally, efforts towards increasing HIV risk perception are central to optimizing adherence.