Cost-effectiveness of overseas testing and treatment for tuberculosis infection among United States-bound refugees: a mathematical modelling analysis

Research in contextO_ST_ABSEvidence before this studyC_ST_ABSPrevious cost-effectiveness analyses have examined tuberculosis (TB) infection testing and latent TB infection (LTBI) treatment among migrants in high-income, low TB-incidence countries, including the United States, Canada, and Australia. These studies found that cost-effectiveness varied by setting, population risk, and intervention design. Refugees and asylum seekers--populations with higher TB exposure and reduced healthcare engagement post-arrival--were identified as high-priority groups. Studies suggested that diagnosis and treatment of LTBI before migrants depart their origin country could improve retention along the care cascade and yield better health and economic outcomes compared to post-arrival interventions. A recent pilot study demonstrated the feasibility of pre-departure TB infection testing and voluntary LTBI treatment among U.S.-bound immigrants in Vietnam. However, a cost-effectiveness analysis examining the addition of pre-departure LTBI treatment to pre-departure testing and post-arrival LTBI treatment for refugee and asylee populations is lacking. Added value of this studyThis model-based cost-effectiveness analysis extends prior work by evaluating the addition of pre-departure LTBI treatment to pre-departure testing and post-arrival LTBI treatment. It demonstrates that a pre-departure offer of LTBI treatment could increase overall treatment completion and enhance both health outcomes and cost-effectiveness. Implications of all the available evidenceIn many settings, recently arrived refugees have some of the highest risks of developing TB disease. Therefore, identifying preventive interventions that can reduce TB risk among the refugee population--in ways that are cost-effective, feasible, and respectful of individual autonomy--is a high public health priority. This study found that pre-departure TB infection testing and voluntary LTBI treatment would be a cost-effective addition to current post-arrival prevention approaches, reducing TB risk for a traditionally underserved population at high risk of TB disease. BackgroundIn the United States, preventing TB among refugee populations is a public health priority. We assessed the health impact and cost-effectiveness of strategies to diagnose and treat latent TB infection (LTBI) among U.S.-bound refugees from high TB incidence countries. MethodsUsing mathematical modelling, we simulated TB-related health outcomes and costs (2023 USD) among individuals entering the United States as refugees, from pre-departure medical evaluation until death. LTBI diagnosis was made via interferon-gamma release assay (IGRA), after ruling out TB disease. We compared three intervention strategies: (1) pre-departure IGRA testing for children (2-14 years) and post-arrival IGRA testing for adults (>14 years), with LTBI treatment offered in the United States; (2) pre-departure IGRA testing for children and adults, with LTBI treatment offered post-arrival; (3) pre-departure IGRA testing for children and adults with LTBI treatment offered pre-departure, then re-offered in the United States for individuals not completing treatment before U.S. arrival. FindingsThe intervention strategies were projected to avert 32-60% lifetime TB cases for children and adults, compared to no IGRA testing or LTBI treatment ( no intervention). Compared to Strategies 1 and 2, Strategy 3 produced greater health gains with lower incremental costs. Compared to no intervention, Strategy 3 had an incremental cost-effectiveness ratio of $45,000 per QALY gained for children, and $21,111 per QALY gained for adults. InterpretationPre-departure IGRA testing and voluntary LTBI treatment could be cost-effective for preventing TB disease among U.S.-bound refugees, when provided in conjunction with existing services to diagnosis and treat TB disease. FundingCDC.