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After decades of intensive effort, the WHO reports declines in the incidence and prevalence of TB in India for recent years. At the same time, there are rising concerns about increases in multidrug resistant (MDR) TB and consequent prospects for future TB control. Much effort has been devoted to developing new technologies and interventions focused on cementing gains and addressing MDR, though their eventual success may hinge on the underlying determinants of India’s TB and MDR TB epidemics. For example, is MDR TB currently a largely treatment-generated phenomenon, and if so, is thisprimarily due to inappropriate treatment in the private healthcare sector or to early dropout or poor treatment quality in the DOTS-based treatment in the public healthcare sector? Perhaps MDR TB transmission is already critical and delays in either seeking treatment, diagnosis or treatment and consequent longer infectious periods are key determinants? Answers to these questions can help to inform policymakers regarding the relative importance of improvements in TB treatment regimens for non-MDR and/or MDR TB in the private and/or public healthcare sectors as well as the role of new rapid diagnostic technologies and/or case finding strategies.
Motivated by these questions, this presentation describes a program of work on TB in India, including a set of field studies focused on TB in the 80 million person population of Bihar, India in the context of a large-scale program evaluation along with detailed microsimulation modeling on TB and MDR TB in India. We characterize patterns and determinants of treatment delays (time between becoming symptomatic for active TB and receiving the first doses of drugs in a DOTS regimen) among patients who ultimately receive TB treatment in the public healthcare system in India. We then detail a study of a representative sample of 1,543 individuals treated for TB within the public healthcare system in Bihar. We describe determinants of early treatment dropout and remaining symptomatic 6 months post-treatment initiation, focusing on whether individuals report prior TB treatment and completion of that prior treatment, their delays in seeking care for their current TB episode, their use of private sector treatment prior to seeking care in the public sector, measures of household poverty, whether they must pay for care that is supposed to be delivered free in the public sector, and their illness severity -- in terms of number of symptoms at the start of treatment. We also describe the micronutrient and macronutrient intakes of households with a TB patient compared to matched households without a TB patient which have implications for immune response and hence ongoing transmission to family members as well as activation of latent TB infections. Finally, we use our microsimulation model to assess the current status and future prospects of India’s TB and MDR TB epidemic in terms of determinants including treatment delays and dropout and the quality of care in the private and public healthcare sectors. We conclude by outlining future planned studies on these and related topics.
Parts of this program of work involve collaborations with PCOR affiliates including Grant Miller, Kim Babiarz, Eran Bendavid, and Sze-chuan Suen. Funding sources include the NIH, the Bill and Melinda Gates Foundation, the Stanford Woods Institute for the Environment, and the Freeman Spogli Institute’s Underdevelopment Action Fund.