Background: Adherence is crucial for public health program effectiveness, though the benefits of increasing adherence must ultimately be weighed against the associated costs. We sought to determine the relationship between investment in community health worker (CHW) home visits and increased attendance at cervical cancer screening appointments in Cape Town, South Africa.
Methodology/principal findings: We conducted an observational study of 5,258 CHW home visits made in 2003-4 as part of a community-based screening program. We estimated the functional relationship between spending on these visits and increased appointment attendance (adherence). Increased adherence was noted after each subsequent CHW visit. The costs of making the CHW visits was based on resource use including both personnel time and vehicle-related expenses valued in 2004 Rand. The CHW program cost R194,018, with 1,576 additional appointments attended. Adherence increased from 74% to 90%; 55% to 87%; 48% to 77%; and 56% to 80% for 6-, 12-, 24-, and 36-month appointments. Average per-woman costs increased by R14-R47. The majority of this increase occurred with the first 2 CHW visits (90%, 83%, 74%, and 77%; additional cost: R12-R26).
Conclusions/significance: We found that study data can be used for program planning, identifying spending levels that achieve adherence targets given budgetary constraints. The results, derived from a single disease program, are retrospective, and should be prospectively replicated.