Culture conversion and drug susceptibility in drug-resistant pulmonary tuberculosis with type 2 diabetes mellitus on oral regimens.

BACKGROUND: The simultaneous existence of multidrug-resistant pulmonary tuberculosis (MDR-PTB) and type 2 diabetes mellitus (T2DM) represents a rising threat in high-burden countries such as India. Diabetes has been associated with impaired immune responses and delayed bacteriological clearance, thereby compromising treatment outcomes in patients with multidrug-resistant tuberculosis receiving all-oral longer regimens. AIM: Impact of T2DM on clinical profile, radiological severity, drug resistance patterns, and sputum culture conversion in MDR-PTB. METHODS: This prospective observational study included 264 adults with microbiologically confirmed MDR-PTB treated at a tertiary care center in North India over a 12-month period. The participants were classified as diabetic, pre-diabetic, or non-diabetic according to the American Diabetes Association 2023 criteria. Clinical, radiological, microbiological, and drug susceptibility data were analyzed. Time to culture conversion and treatment outcomes were compared across groups using appropriate statistical tests. RESULTS: Patients with diabetes were older and had higher rates of dyspnea and hemoptysis. Radiologically, they demonstrated significantly higher rates of bilateral lung involvement and lower zone involvement. A higher bacillary load and increased prevalence of inhA and katG mutations were observed among patients with diabetes. Mean time to sputum culture conversion was significantly prolonged in patients with diabetes (132.9 ± 22.3 days) compared with pre-diabetic patients (112.6 ± 7.6 days) and non-diabetic patients (96.9 ± 10.8 days) (P < 0.001). CONCLUSION: T2DM adversely affects bacteriological response, radiological severity, and treatment outcomes in patients with MDR-PTB on all-oral longer regimens.