Modelling the potential impact of adherence technologies on tuberculosis in India.

BACKGROUND: For patients taking standard first-line tuberculosis treatment, missing 10% or more of their doses increases the risk of relapse six-fold. Digital technologies offer new approaches to adherence support for TB patients. We estimated the potential impact of new adherence technologies in India. METHOD: We developed a mathematical model of TB transmission dynamics in India, capturing the independent effects of missed doses and treatment default on post-treatment recurrence. We simulated the impact of interventions to address both missed doses and treatment default in the public and private healthcare sector. RESULTS: Adherence interventions, if deployed optimally in the public sector alone, would reduce cumulative TB incidence by 7.3% (95% credible intervals [CrI] 4.7-11) between 2020 and 2030, and by 16% (95% CrI 11-23) if also deployed in the private sector. This impact is roughly proportional to the effectiveness of the interventions. Reducing missed doses reduced incidence by 12% (95% CrI 7.0-18), while reducing treatment default reduced incidence by 7.9% (95% CrI 3.2-13). CONCLUSION: Minimising missed doses is at least as important as promoting treatment completion. Our results suggest that emerging technologies to improve treatment adherence could have a substantial impact on TB incidence and mortality in India.