Frontiers in Tropical Diseases · Published 2026-06-23 · DOI 10.3389/fitd.2026.1858544
Mehul Saxena, Rashmi Ratnam, Parul Jain, Harshit Flodia, Kajal Prajapati, R. A. S. Kushwaha, Amita Jain, Urmila Singh
BackgroundThe dual burden of tuberculosis (TB) and diabetes mellitus (DM) is rising rapidly in low- and middle-income countries, yet evidence on the effect of diabetes on early treatment response under routine programmatic conditions in India remains limited. Understanding determinants of sputum culture conversion is critical for improving TB outcomes. This study aimed to evaluate the impact of diabetes mellitus and socio-demographic factors on time to sputum culture conversion among patients with pulmonary tuberculosis.MethodsWe conducted a retrospective cohort study of 100 adult patients with bacteriologically confirmed pulmonary TB (50 with DM and 50 without) at a tertiary care centre in North India (January 2023–January 2024). Data were obtained from laboratory records, the Ni-kshay portal, and telephonic interviews. Time to sputum culture conversion was analyzed using Kaplan–Meier methods with log-rank testing, and independently associated factors were identified using Cox proportional hazards regression.ResultsPatients with diabetes were significantly older and socio-demographically distinct from non-diabetic patients. Median time to sputum culture conversion was longer in the diabetic group (24.14 weeks vs. 18.36 weeks days; p = 0.002). In multivariable analysis, diabetes was identified as an independently associated factor of delayed conversion (aHR = 0.66; 95% CI: 0.52–0.84; p value: 0.001). Additional factors associated with delayed conversion included older age (aHR 0.78;p value: 0.03), low socioeconomic status (aHR 0.73; p value: 0.002), smoking (aHR 0.68; p value: 0.001), and alcohol use (aHR 0.74; p value: 0.006), while urban residence was associated with faster conversion (aHR 1.22; p value: 0.04).ConclusionDiabetes mellitus and socioeconomic disadvantage are significantly associated with delayed sputum culture conversion in pulmonary TB, underscoring the need for integrated TB–diabetes care, risk-stratified follow-up, and targeted public health interventions to improve outcomes in high-burden settings.
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Saxena, M., Ratnam, R., Jain, P., et al. (2026). Determinants of time to sputum culture conversion in pulmonary tuberculosis: role of diabetes and socioeconomic disadvantage in India. Frontiers in Tropical Diseases. https://doi.org/10.3389/fitd.2026.1858544