Equity Implications of Kenya’s Dual HIV/Syphilis Antenatal Testing Strategy: A Distributional Cost-Effectiveness Analysis

Abstract

Background: Dual HIV/syphilis rapid diagnostic testing at antenatal care (ANC) has been shown to be cost-saving at the national level in Kenya. Whether health gains from this strategy are distributed proportionally between rural and urban pregnant women is unknown. Rural women account for approximately 69% of Kenya's modeled annual pregnancy population but may face weaker ANC cascade performance, including later ANC initiation, lower testing completion, and weaker treatment linkage. Methods: We adapted a published Excel-based Markov decision analytic model of antenatal HIV/syphilis testing in Kenya to examine rural-urban distributional implications. Rural and urban model runs used subgroup-specific service delivery parameters. The analysis was conducted from a healthcare system perspective, with a cost-effectiveness threshold of US$596 per disability-adjusted life year (DALY) averted. Distributional outcomes included DALYs averted per 1,000 pregnant women, health-gain shares relative to population shares, exploratory health opportunity-cost-based net health benefit, and an ANC cascade equalization analysis. One-way sensitivity analyses assessed robustness of efficiency and equity findings.Results: Dual testing at first ANC was cost-saving in both rural and urban model scenarios. Adding late ANC dual retesting generated additional health gains below the selected threshold in both subgroups, with ICERs of US$215 per DALY averted in rural populations and US$226 per DALY averted in urban populations; the combined Kenya estimate was US$219 per DALY averted. Assuming only first-ANC-only dual testing, rural women received 58.9% of total health gains despite comprising 69% of the modeled annual pregnancy population, with a per-capita urban-rural benefit gap of 2.49 DALYs averted per 1,000 pregnant women. Adding late ANC retesting narrowed this gap to 0.57 and moved the rural share of health gains to 67.4%, close to the rural population share. The cascade equalization analysis identified treatment uptake as the cascade stage most strongly associated with modeled rural-urban differences, followed by testing uptake; ANC contact alone had a smaller effect. Efficiency conclusions were robust across all one-way sensitivity ranges; equity results were most sensitive to ANC timing and first ANC attendance. Conclusions: Dual HIV/syphilis testing is cost-saving at first ANC and remained cost-effective with late ANC retesting in both urban and rural subgroups, supporting prior national cost-effectiveness evidence from Kenya. Strengthened late ANC retesting narrowed the urban–rural per-capita benefit gap and moved rural and urban health-gain shares closer to their shares of the modeled pregnancy population. The equity impact of dual testing depends on completion of the ANC pathway, particularly testing completion and timely treatment, after diagnosis.