For pre-exposure prophylaxis (PrEP) and microbicides to effectively prevent HIV, optimal treatment adherence is required. Adherence to these strategies, however, has not been sufficiently studied. This investigation systematically reviews oral PrEP and microbicide trials across 4 domains of adherence: (1) definition and measures used, (2) risks for nonadherence, (3) promotion strategies, and (4) effects on outcomes. Nineteen (n = 19) trials, with 47,157 participants, published between 1987 and 2012 were identified. Reported mean adherence to microbicides was 79% and to oral PrEP 87%. Common risks for microbicide nonadherence were decreased motivation over time, sex with primary (noncommercial/casual) partners, and insufficient supply. Oral PrEP nonadherence risks were older age and medication side effects. Psychoeducation and outreach to participants and communities were frequently used promotion strategies. Most trials failed to systematically identify barriers and monitor and promote adherence, although adherence moderated outcomes. Recommendations for attending to adherence in future trials are provided.
*Global Health Research Center of Central Asia, Columbia University, New York, NY
†Social Intervention Group, Columbia University, School of Social Work, Columbia University, New York, NY
‡Columbia University, New York, NY
§Department of Psychology, University of Washington, Seattle, WA.
Correspondence to: Felix M. Muchomba, MPH, Global Health Research Center of Central Asia, Columbia University, 1255 Amsterdam Avenue, New York, NY 10027 (e-mail: email@example.com).
J.M. Simoni is supported by the National Institute to Mental Health (K24MH093243) and the University of Washington Center for AIDS Research (CFAR), a National Institutes of Health–funded program (P30 AI27757). N. El-Bassel is supported by the National Institute of Drug Abuse (R01DA022914).
The authors have no conflicts of interest to disclose.
Received May 7, 2012
Accepted August 16, 2012