We reviewed 25 randomized clinical trials that assessed the effect of peer-based interventions on health-related behaviors in adults. Effect sizes were calculated as odds ratios or standardized mean differences. We grouped most of the studies by 7 measured outcomes, with effect sizes ranging from −0.50 to 2.86. We found that peer-based interventions facilitated important changes in health-related behaviors, including physical activity, smoking, and condom use, with a small-to medium-sized effect. However, the evidence was mixed, possibly because of the heterogeneity we found in methods, dose, and other variables between the studies. Interventions aimed at increasing breastfeeding, medication adherence, women's health screening, and participation in general activities did not produce significant changes.Peer-based interventions have become a common method to effect important health-related behavior changes. 1,2 However, no generally accepted definition of peer or peer-based intervention has been established to date. Peers often share a common culture, language, and knowledge about the problems that their community experiences. 3 Moreover, in the research context, peers must share a health problem (e.g., newly diagnosed tuberculosis) or a potential for change in their health status (e.g., breastfeeding for new mothers). For this review, we defined peer-based interventions as a method of teaching or facilitating health promotion that asks people to share specific health messages with members of their own community. 3 Correspondence can be sent to Dr Allison Webel, Frances Payne Bolton School of Nursing, 10900 Euclid Ave, Cleveland,. Reprints can be ordered at http://www.ajph.org by clicking the "Reprints/Eprints" link. ContributorsA. R. Webel originated the study, completed the analyses, and led the writing. J. Okonsky assisted with the analyses and writing. J. Trompeta assisted with the study and analyses. W. L. Holzemer assisted with the study and supervised all aspects of its implementation. All authors conceptualized ideas, interpreted findings, and reviewed drafts of the article. Human Participant ProtectionNo protocol approval was required because the data were obtained from secondary sources. Over the past 20 years a growing body of literature has examined the efficacy of peer-based interventions to improve health care. These studies have examined a variety of illnesses, conditions, populations, and interventions to determine what can be done at the community level to facilitate positive health care outcomes. In addition, numerous studies have tested new ways to reach minority populations and to decrease health care spending. Outcomes measures in these studies have included improved quality of life, improved self-efficacy, increased selfcare and symptom management, and reduction in harmful behaviors. 1 These studies have concluded that peer-based interventions have the potential to enhance health equity in persons living with disease. 1,3-5 Examples of behaviors targeted include physical activity, 6 ...

Objective To test the impact of participation in a peer-based intervention for symptom management for women living with HIV infection on selected outcome measures including, symptom intensity, medication adherence, viral control, and quality of life. Design Randomized clinical trial. Methods Participants were recruited using a convenient, consecutive sampling method. Those participants randomized to the experimental condition attended seven, peer-led sessions over seven weeks. Participants randomized to the control condition received a copy of HIV Symptom Management Strategies: A Manual for People Living with HIV/AIDS. Participants completed four surveys assessing change over time in the aforementioned outcome variables. Results Eighty-nine HIV-infected women followed over 14 weeks and there were no differences between the two groups on baseline demographic variables. Mixed-effects regression indicated no significant difference between groups across time in total symptom intensity score and medication adherence. There was a significant difference between groups across time for two of the nine quality of life scales – HIV Mastery (χ2 = 25.08; p < 0.005) and Disclosure Worries (χ2 = 24.67; p < 0.005). Conclusions In urban-dwelling women living with HIV/AIDS, results suggest that a peer-based symptom management intervention may not decrease symptom intensity or increase medication adherence. There is positive evidence that suggests that the intervention may increase some important aspects of quality of life. However, further research is warranted to elucidate the effect of peer-based interventions in achieving positive self-management outcomes.