Thirteen studies were included in the review (n=24,756): four RCTs and nine quasi-randomised controlled trials. Only three studies met all quality criteria. All studies used clustering sampling. Only two RCTs had adequate allocation sequence and concealment. Blinding of outcome assessors was not reported in any RCT. No study met all Harden and colleagues’ recommendations for the evaluation of peer-led interventions.
There was no significant difference in condom use at last sex for groups who received peer-led interventions compared with controls (adjusted OR 1.04, 95% CI 0.85 to 1.28; seven studies). Significant heterogeneity was found for this outcome (I2=77%).
Three studies reported a non-significant benefit on consistent condom use for the intervention groups compared with controls. One study reported that peer-led interventions significantly reduced the risk of chlamydia (OR 0.17, 95% CI 0.03 to 0.92), but another study found no significant impact on the incidence of sexually transmitted diseases. One study reported a significant increase in the odds that female adolescents had never had sex (OR1.88, 95% CI 1.02 to 3.47), but no effect among males.
There was no evidence of publication bias. Results for other outcomes and subgroup analyses were reported.