Survival analysis of risk factors for mortality in pulmonary tuberculosis patients in southeast Iran (2013-2023).

BACKGROUND: Tuberculosis (TB) remains a major global health challenge, particularly in low- and middle-income countries. In Iran, Sistan-and-Baluchistan Province bears a disproportionately high burden of pulmonary tuberculosis due to its geographic, socioeconomic, and healthcare access-related vulnerabilities. Despite national control programs, evidence on survival outcomes and mortality predictors in this region remains limited. OBJECTIVE: This study aimed to determine the survival time and identify key risk factors associated with mortality among smear-positive pulmonary tuberculosis (SPPTB) patients in Sistan-and-Baluchistan Province, southeast Iran. METHODS: In this retrospective cohort study, data from 7,234 SPPTB patients were collected from 2013 to 2023. Information was analyzed using Kaplan-Meier survival estimates, log-rank tests, and multivariable Cox proportional hazards models. Survival time was calculated from the date of the SPPTB diagnosis to the date of death or censoring due to treatment completion, cure, failure, or loss to follow-up. Statistical analyses were conducted using SPSS version 22, with significance set at p < 0.05. RESULTS: Among the study population, 526 patients (7.3%) died during treatment. The median survival time was 20.5 months (95% CI: 12.15-28.54). The findings revealed that advanced age, prisoner status, low BMI, Iranian nationality, rural residency, and HIV co-infection were significant predictors of mortality. CONCLUSION: The study highlights several key risk factors associated with SPPTB-related mortality in a high-burden region of Iran. These findings emphasize the need for targeted interventions, particularly for elderly, malnourished, HIV-positive, and incarcerated individuals, as well as the integration of nutritional and HIV care into SPPTB control programs. Early detection, improved follow-up, and structural support in underserved settings are essential to reduce mortality and align with WHO End TB Strategy targets. CLINICAL TRIAL NUMBER: Not Applicable.