Cost-Effectiveness of Community Tuberculosis Screening in South Africa

RATIONALE: The World Health Organization recommends community-based tuberculosis active case finding using digital chest radiography with computer-aided detection (dCXR/CAD) and/or molecular diagnostics, but clinical and economic outcomes are unclear. OBJECTIVE: To evaluate the cost-effectiveness of community-based tuberculosis screening strategies in South Africa. METHODS: Using a microsimulation model, we evaluated three symptom-agnostic screening strategies among adult people without HIV (PWoH) and people with HIV (PWH): (1) No Screening; (2) sputum Xpert Ultra (Xpert); and (3) dCXR/CAD followed by confirmatory sputum Xpert (dCXR + Xpert). Base case tuberculosis prevalence was 0.64%-1.23%. Sensitivity/specificity/cost for dCXR/CAD were 77-90%/65-73%/$3.55; for Xpert Ultra, they were 69-91%/98-99%/$15.24. Model outcomes included life-years, costs, and incremental cost-effectiveness ratios (ICERs) (<$3,000/year-of-life saved [YLS] considered cost-effective). We conducted sensitivity analysis around key parameters, including test sensitivity, specificity, and cost. MEASUREMENTS AND MAIN RESULTS: In the base case, Xpert identifies the most individuals with tuberculosis but produces the most false-positives and highest costs. Compared to Xpert, dCXR + Xpert identifies ∼13% fewer individuals with tuberculosis while decreasing screening costs by ∼45%. Given base case performance characteristics, at the lifetime horizon, dCXR + Xpert is cost-effective (ICER $610/YLS) while Xpert is not (ICER $3,460/YLS). dCXR + Xpert remains cost-effective relative to No Screening unless tuberculosis prevalence (PWoH/PWH) is ≤ 0.15%/0.45%, dCXR/CAD sensitivity is (PWoH/PWH) ≤ 20%/10%, dCXR/CAD cost is ≥$34.00, Xpert Ultra cost is ≥$135.00, or linkage to tuberculosis care is ≤ 15%. CONCLUSION: Digital chest radiography with computer-aided detection followed by confirmatory sputum Xpert Ultra would likely be a cost-effective strategy for tuberculosis screening in South Africa.