Cost-effectiveness of community tuberculosis screening in South Africa.

Abstract

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. To evaluate the cost-effectiveness of community-based tuberculosis screening strategies in South Africa. Using a microsimulation model, we evaluated 3 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) (<$3000/year-of-life saved [YLS] considered cost-effective). We conducted sensitivity analysis around key parameters, including test sensitivity, specificity, and cost. 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) whereas Xpert is not (ICER $3460/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%. 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.