Treatment outcomes and influencing factors of older patients with pulmonary tuberculosis complicated with diabetes mellitus in China, 2018–2024

Background The comorbidity of pulmonary tuberculosis (PTB) and diabetes mellitus (DM) is rising among adults aged ≥ 65 years in China. DM comorbidity significantly worsens PTB treatment outcomes. Population-based evidence specific to older Chinese PTB-DM patients remains scarce. This retrospective cohort study aimed to identify independent risk factors for adverse treatment outcomes in older Chinese PTB-DM patients. Methods Data were from the National Tuberculosis Information Management System (2018–2024). Kaplan–Meier analysis was performed to estimate overall event-free survival. Fine–Gray competing risks regression models were used to identify independent factors associated with each adverse outcome subtype, accounting for competing events. Results Among 56,682 eligible patients, the median follow-up duration was 6.965 months, and the rate of adverse anti-tuberculosis treatment outcomes was 11.08%. Irregular treatment adherence ( aHR = 12.783, 95%CI : 12.008–13.607), male sex ( aHR = 1.246, 95%CI : 1.176–1.319), increased age ( aHR = 1.345–2.459), retreatment ( aHR = 1.112, 95%CI : 1.031–1.199), positive etiological test results ( aHR = 1.338, 95%CI : 1.259–1.421), comorbidities other than diabetes ( aHR = 1.234, 95%CI : 1.154–1.320), and non-guideline-concordant regimens, ( aHR = 1.096, 95%CI : 1.025–1.171) were independent risk factors for adverse treatment outcomes. Conclusions Adverse treatment outcomes in older adults with PTB-DM are driven by a range of demographic, clinical and adherence-related factors, with irregular medication adherence being the most robust predictor. These risk factors differ across adverse outcome subtypes.