A large increase in lay health care workers has occurred in response to shortages of professional health care staff in sub-Saharan African antiretroviral treatment (ART) programs. However, little effectiveness data of the large-scale implementation of these programs is available. We evaluated the effect of a community-based adherence-support (CBAS) program on ART outcomes across 57 South African sites. CBAS workers provide adherence and psychosocial support for patients and undertake home visits to address household challenges affecting adherence. An observational multicohort study of adults enrolling for ART between 2004 and 2010 was performed. Mortality, loss to follow-up, and virological suppression were compared by intention to treat between patients who received and did not receive CBAS until 5 years of ART, using multiple imputation of missing covariate values. Of the 66,953 patients who were included, 19,668 (29.4%) patients received CBAS and 47,285 (70.6%) patients did not. Complete-case covariate data were available for 54.3% patients. After 5 years, patient retention was 79.1% [95% confidence interval (CI): 77.7% to 80.4%] in CBAS patients versus 73.6% (95% CI: 72.6% to 74.5%) in non-CBAS patients; crude hazard ratio (HR) for attrition was 0.68 (95% CI: 0.65 to 0.72). Mortality and loss to follow-up were independently lower in CBAS patients, adjusted HR (aHR) was 0.65 (95% CI: 0.59 to 0.72) and 0.63 (95% CI: 0.59 to 0.68), respectively. After 6 months of ART, virological suppression was 76.6% (95% CI: 75.8% to 77.5%) in CBAS patients versus 72% (95% CI: 71.3% to 72.5%) in non-CBAS patients (P < 0.0001), adjusted odds ratio was 1.22 (95% CI: 1.14 to 1.30). Improvement in virological suppression occurred progressively for longer durations of ART [adjusted odds ratio was 2.66 (95% CI: 1.61 to 4.40) by 5 years]. Patients receiving CBAS had considerably better ART outcomes. Further scale-up of these programs should be considered in low-income settings.
