Abstract

Background: Improved diagnosis of tuberculosis (TB) is a high priority in people living with HIV/AIDS. A lateral flow assay is now available for point-of-care detection of lipoarabinomannan (LAM, a cell wall component of Mycobacterium tuberculosis) in urine. This assay improves sensitivity of TB diagnosis in highly immunocompromised individuals, but its cost-effectiveness is uncertain. Methods: We incorporated data from a clinical evaluation of lateral-flow urine LAM into a decision-analytic cost-effectiveness model.Our study cohort consisted of hospitalized, HIV-infected South African adults with CD4+ T-cell counts < 100 cells/μL, clinical consideration of TB diagnosis, and access to sputum smear microscopy. Our primary outcome was the incremental cost-effectiveness ratio (ICER), expressed in 2010 US dollars per disability-adjusted life year (DALY) averted from the perspective of a public-sector TB control program. We adopted a lifetime time horizon with 3% discounting and performed both sensitivity analysis and probabilistic uncertainty analysis. Results: For every 1000 patients tested, adding lateral-flow urine LAM to microscopy generated 80 incremental appropriate TB treatments and averted 58 DALYs, at a cost of $1370 per DALY averted (95% uncertainty range: $710-$3396). The majority of incremental costs reflected TB treatment. Incremental cost-effectiveness was most sensitive to assay specificity, cost of TB treatment, life expectancy after TB cure, and cohort TB prevalence. The probability of acceptability was 98.3% at a per-DALY willingness-to-pay threshold equal to per-capita gross domestic product ($7275). Conclusions: Lateral-flow detection of urinary LAM is potentially cost-effective for TB diagnosis in severely immunocompromised South African adults. Cost-effectiveness can be maximized by deploying this assay in populations with high TB prevalence,adopting treatment thresholds that optimize specificity, and promptly delivering antiretroviral therapy to extend patients' life expectancy following cure.