Epidemiological impact of targeted interventions for people with diabetes mellitus on tuberculosis transmission in India: Modelling based predictions

Introduction: Diabetes mellitus (DM) is a leading driver of tuberculosis (TB) disease in TB-DM burdened countries. We aimed to assess the impact on TB disease of several intervention strategies targeting people with DM in India. Methods: A previously validated TB-DM mathematical model was extended to include interventions targeting DM individuals. The model stratified the population by age, DM status, TB infection status and stage, TB disease form, treatment, recovery, and intervention status. Results: By 2050, different TB vaccination strategies (coverage of 50 % and vaccine efficacies ranging between 50 %-60 %) reduced TB incidence and mortality rates by 4.5 %-20.8 % and 4.1 %-22.1 %, respectively, and averted 3.1 %-12.8 % of TB disease cases in the total population. Number of vaccinations needed to avert one TB case (effectiveness) was 14-105. Varying the coverage levels of latent TB treatment (coverage of 50 %-80 % and drug effectiveness of 90 %) reduced TB incidence and mortality rates by 7.1 %-11.3 % and 8.2 %-13.0 %, respectively, averting 4.2 %-6.7 % of TB cases, with effectiveness of 38-40. Different scenarios for dual and concurrent treatment of those with TB and DM, reduced TB incidence and mortality rates by 0.1 %-0.4 % and 1.3 %-4.8 %, respectively, averting 0.1 %-0.2 % of TB cases, with effectiveness of 28-107. Different scenarios for managing and controlling DM (regardless of TB status) reduced TB incidence and mortality rates by 4.5 %-16.5 % and 6.5 %-22.2 %, respectively, averting 2.9 %-10.8 % of TB cases, with effectiveness of 6-24. Conclusion: Gains can be attained by targeting DM individuals with interventions to reduce TB burden. Most strategies were effective with < 50 intervention doses needed to avert one TB disease case, informing key updates of current treatment guidelines.