Long-term follow-up of contacts of drug-resistant tuberculosis cases in high-burden areas of Mumbai, India

Abstract

BackgroundDrug-resistant tuberculosis (DRTB) is a significant public health threat particularly in high burden areas like Mumbai, India. Contacts of DRTB cases are highly vulnerable to infection and development of active disease. In this study we assess long-term outcomes of contacts of DRTB cases, focusing on active TB development and the potential role of IGRA, vitamin D status and supplementation. MethodsA cohort of 262 DRTB contacts identified from a prior case-control study conducted in Mumbai were enlisted for the study. Interviews were conducted, and data were analysed using descriptive statistics and logistic regression. ResultsOf the 262 contacts, 34.73% had LTBI. Three contacts (1.36%) developed active TB, with a crude incidence rate of 4.64 per 1000 people. Vitamin D deficiency was prevalent in 75.3% of contacts, and all three TB cases were vitamin D deficient. Vitamin D supplementation showed a non-significant trend in reducing TB risk (OR = 0.56, p = 0.492). IGRA status did not significantly predict TB development. ConclusionThis study provides valuable insights into the long-term outcomes of contacts of DRTB cases. While baseline IGRA did not prove to predict development of active TB, association between vitamin D deficiency and TB development highlights the need for larger studies and development of more effective screening tools. The study contributes valuable information to TB control strategies in high-burden areas.