Adherence in Pre-Exposure Prophylaxis and Microbicide Trials
Adherence in Pre-Exposure Prophylaxis and Microbicide Trials
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.
Significant strides in HIV prevention have been achieved through the use of active pharmaceutical agents with individuals at risk but currently HIV-negative. These agents include antiretroviral treatments administered orally [ie, oral pre-exposure prophylaxis (PrEP)] and antimicrobial gels, creams, and films applied topically (ie, microbicides). The effectiveness of PrEP in reducing incidence of HIV is strongly supported, and the evidence on the use of microbicides is promising.
While these interventions are typically referred to as biomedical prevention strategies, in reality, they are better characterized as bio-behavioral because of the significant behavioral factors that seem to impact their implementation and moderate their efficacy. Perhaps most importantly, individual adherence to the prevention protocols seems paramount to optimal response, yet may be difficult to achieve in those who are currently HIV-negative. Despite advances in adherence research and strategies in antiretroviral therapy, adherence to these bio-behavioral prevention strategies (B-BPSs) remains underdeveloped and underresearched. Adherence barriers encountered in antiretroviral therapy, such as depression, substance use, inadequate patient–provider relationships, lack of social support, negative publicity, stigma, migration, poverty, inconvenient dosing frequency, distance to health facility, lack of coordination across health services, and limited involvement of community in program planning, may impede adherence to B-BPSs. Investigation of adherence barriers and strategies to promote adherence is therefore required, for which effective adherence measurement is essential.
This systematic review examines: (1) definitions and measures used for adherence in oral PrEP and microbicide research; (2) the individual-, partner-, agency-, community-, or structural-level risks for nonadherence; (3) strategies/interventions used to promote adherence; and (4) effects of adherence on the major outcomes. Based on the review, recommendations for future research and implementation of B-BPSs are offered.
Abstract and Introduction
Abstract
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.
Introduction
Significant strides in HIV prevention have been achieved through the use of active pharmaceutical agents with individuals at risk but currently HIV-negative. These agents include antiretroviral treatments administered orally [ie, oral pre-exposure prophylaxis (PrEP)] and antimicrobial gels, creams, and films applied topically (ie, microbicides). The effectiveness of PrEP in reducing incidence of HIV is strongly supported, and the evidence on the use of microbicides is promising.
While these interventions are typically referred to as biomedical prevention strategies, in reality, they are better characterized as bio-behavioral because of the significant behavioral factors that seem to impact their implementation and moderate their efficacy. Perhaps most importantly, individual adherence to the prevention protocols seems paramount to optimal response, yet may be difficult to achieve in those who are currently HIV-negative. Despite advances in adherence research and strategies in antiretroviral therapy, adherence to these bio-behavioral prevention strategies (B-BPSs) remains underdeveloped and underresearched. Adherence barriers encountered in antiretroviral therapy, such as depression, substance use, inadequate patient–provider relationships, lack of social support, negative publicity, stigma, migration, poverty, inconvenient dosing frequency, distance to health facility, lack of coordination across health services, and limited involvement of community in program planning, may impede adherence to B-BPSs. Investigation of adherence barriers and strategies to promote adherence is therefore required, for which effective adherence measurement is essential.
This systematic review examines: (1) definitions and measures used for adherence in oral PrEP and microbicide research; (2) the individual-, partner-, agency-, community-, or structural-level risks for nonadherence; (3) strategies/interventions used to promote adherence; and (4) effects of adherence on the major outcomes. Based on the review, recommendations for future research and implementation of B-BPSs are offered.
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