Effectiveness of antiretroviral treatment in a South African program: a cohort study.

Background: The effectiveness of the South African government's expanding antiretroviral treatment program is unknown. Observational studies of treatment effectiveness are prone to selection bias, rarely compare patients receiving antiretroviral treatment with similar patients not receiving antiretroviral treatment, and underestimate mortality rates unless patients are actively followed up.

Methods: We followed up 14 267 patients in the Public Sector Anti-Retroviral Treatment project in Free State, South Africa, for up to 20 months after enrollment.