Informing Decision-Making for Universal Access to Quality Tuberculosis Diagnosis in India: An Economic-Epidemic Model

Background: India and many other high-burden countries have committed to providing universal access to high-quality diagnosis for tuberculosis (TB), but the most cost-effective approach to achieve this goal remains uncertain. Centralized testing can generate economies of scale, but decentralization may provide faster diagnosis and reduce losses to follow-up (LTFU).   Methods: We generated functions to evaluate the costs of centralized and decentralized molecular testing for tuberculosis with Xpert MTB/RIF (Xpert). We merged the cost estimates with an agent-based simulation of TB transmission in a hypothetical emblematic region in India to assess the impact and cost-effectiveness of each strategy.   Results: Compared against centralized Xpert testing, decentralization was most favorable when testing volume at decentralized facilities and pre-treatment LTFU were high, and specimen transport network was exclusively established for TB. Assuming equal quality of centralized and decentralized testing, decentralization was cost-saving, saving a median $338,000 (interquartile simulation range [IQR]: -$222,000; $889,000) per 20 million people over ten years, in the most cost-favorable scenario. In the most cost-unfavorable scenario, decentralized testing would cost a median $3,161 [IQR: $2,412; $4,731] per disability-adjusted life year averted relative to centralized testing.   Interpretation:  Decentralization of Xpert testing is likely to be cost-saving or cost-effective in most settings to which these simulation results might generalize, particularly those with moderate-to-high peripheral testing volumes, high existing clinical LTFU, inability to share specimen transport costs with other disease entities, and ability to ensure high-quality peripheral Xpert testing. Decision makers should assess these factors when deciding whether to decentralize molecular testing for tuberculosis.   Funding Statement: TB Modelling and Analysis Consortium (Bill and Melinda Gates Foundation, OPP1084276) and Fonds de Recherche Sante Post-Doctoral Fellowship training award (36095) Declaration of Interests: The authors have no competing interests. Ethics Approval Statement: Ethics approval not required.