Factors associated with mortality in tuberculosis patients

BACKGROUND: Tuberculosis (TB) is one of the main causes of morbidity and mortality in different societies. Understanding factors leading to death following diagnosis of TB is important to predict prognosis in TB patients. The aim of this study was to identify common risk factors associated with death in patients with an in-hospital diagnosis of TB, in a city in Iran with the highest prevalence and incidence of TB in the country. MATERIALS AND METHODS: A retrospective study was conducted at a university-affiliated hospital, Zahedan, in the south-east of Iran, which is a referral center for TB. To identify factors leading to death, medical records of 715 patients ≥15 years old with pulmonary TB from February 2002 to February 2011 have been evaluated. Registered factors included smoking, human immune deficiency virus (HIV) infection, using drugs, lung cancer, drug hepatitis following anti-TB medications, diabetes mellitus, previous TB treatment, anemia; and results of sputum smears. Univariate comparison and multiple logistic regression were performed to identify factors associated with mortality in TB patients. RESULTS: Among 715 registered TB patients, 375 (52.5%) patients were male; among those, 334 (53%) were in the alive group and 41 (54%) in the death group. Seventy-five (10.5%) of the total number of TB patients died during TB treatment. The multivariate model showed that anemia (AOR: 19.8, 95% CI: 5.6-35.5), positive sputum smear (AOR: 13.4, 95% CI: 6.8-33.6), smoking (AOR: 12.9, 95% CI: 3.9-27.3), drug hepatitis (AOR: 12.3, 95% CI: 6.7-24.7), diabetes mellitus (AOR: 9.7, 95% CI: 2.9-32.0), drug use (AOR: 7.8, 95% CI: 2.4-25.5), and history of previous TB (AOR: 6.8, 95% CI: 2.2-21.3) were major risk factors for death in TB patients. CONCLUSION: Monitoring co-morbid conditions like diabetes mellitus and anemia are important to reduce death rate in TB patients. Preventive measures for smoking and drug addiction also play an important role to decrease mortality. Follow-up of patients with previous TB treatment is recommended.