Risk factors of mortality in patients with multi-drug resistant TB

Background: Multi-drug resistant TB (MDR-TB) occurs when the causative agent, Mycobacterium tuberculosis, becomes resistant to isonazid and rifampin, the two most effective drugs commonly used to treat TB. Despite high rates of MDR-TB in Ethiopia, little data exist on the prevalence of or risk factors for drug-resistant tuberculosis. Objective: The aim of the current study was to identify risk factors that are associated with MDR-TB in patients from the All Africa Leprosy, Tuberculosis and Rehabilitation Training Center (ALERT), Addis Ababa, and Gondar University Teaching and Referral Hospital, Gondar, Ethiopia. Methods: The study included 342 MDR-TB patients (142 from ALERT and 200 from Gondar) who had been under treatment from August 2011 to August 2014 and for whom data for the variables of interest were complete. Descriptive statistics, univariate and multivariate survival analyses were applied. The Kaplan-Meier method was used to estimate overall survival longevity as well as survival levels by covariates. The proportional hazards regression model was employed to identify covariates that have effect on the survival of MDR-TB patients. Results: Out of the total 342 subjects, 37(10.8%) died before the end of the follow-up period (August 2011 to September 2014); 11 and 12 deaths occurred in the first and second three-months of MDR-TB treatment followup, respectively. The median survival for MDR-TB patients was 16 months. Covariates associated with increased risk of mortality were: having clinical complications, resistance to Isoniazid (INH), Rifampicin (RIF) and at least one of other drugs (Ethambutol (E), Streptomysin (STM), Kanamycin (KAN), Amikacin (AMK) & Capreomycin (CPM)), smoking, body weight and age. Conclusion: The mortality rate of patients was high at the earlier stages of treatment. The three laboratory and clinical factors (complication, resistance to drugs, smoking) were found to have significant association with increased risk of mortality.