Improving the tuberculosis infection care cascade among migrants in Canada: a cost-effectiveness modelling study.

BACKGROUND: Tuberculosis elimination requires expanded use of preventive treatment. However, adherence to the tuberculosis infection cascade of care is often an issue, notably in vulnerable groups such as migrants. We aimed to assess a person-centred approach to tuberculosis screening and treatment using facilitators, comparing strategies for tuberculosis prevention among new migrants to Canada.

METHODS: We modelled a cohort of 100 000 adults representing the demographic profile of migrants from countries with an annual tuberculosis incidence of 50 cases or higher per 100 000 population. A Markov model estimated tuberculosis-service payer costs (2023 CAN$), tuberculosis episodes, and quality-adjusted life-years (QALYs) over a 20-year analytic horizon. We estimated the cost per tuberculosis episode averted and QALYs gained between the status quo, and screening and treatment with and without facilitators. Facilitators included interpreters, peer navigators, educational materials, and text message reminders.

FINDINGS: The status quo strategy was projected to cost a total of $13·6 million (95% uncertainty range [95% UR] 10·6-17·2) per 100 000 migrants, resulting in 655 cases (596-712) of tuberculosis, 30 tuberculosis-related deaths (20-40), and 1·4 million QALYs per 100 000 population (1·2-1·5). When compared with the status quo, screening strategies with facilitators prevented more tuberculosis episodes and deaths, and resulted in greater gains in QALYs than corresponding strategies without facilitators. Although strategies with facilitators had higher costs than those without, costs per tuberculosis episode averted and QALYs gained were lower than corresponding strategies without facilitators when compared with the status quo. Compared with the status quo, expanded screening with facilitators prevented 375 cases (250-483) of tuberculosis, 17 tuberculosis-related deaths (6-28), and resulted in a gain of 235 QALYs (13-460); this corresponded to incremental costs of $53 050 per tuberculosis episode averted and $84 159 per QALY gained when compared with the status quo.

INTERPRETATION: Interpreters, peer navigators, educational materials, and text message reminders can improve the yield and cost-effectiveness of screening and treatment for tuberculosis infection among migrants. Future prevention strategies should incorporate such facilitators.

FUNDING: Canadian Institutes of Health Research and Caen University Hospital.