Risk factors for mortality among drug-resistant tuberculosis patients registered for drug-resistant treatment in Amhara region, Ethiopia: a historical cohort study

BACKGROUND: The emergency of drug resistant tuberculosis is a major public health concern worldwide including Ethiopia. However, little is known about risk factors of mortality among drug resistant tuberculosis patients in the study site. Thus, this study was aimed to estimate the risks factors for mortality among drug resistant tuberculosis patients registered for drug-resistant treatment in Amhara region, Ethiopia. METHODS: An institutional-based retrospective cohort study was carried out among laboratory-confirmed drug-resistant tuberculosis patients (n = 498) who were initiated treatment for drug-resistant tuberculosis between September 1, 2010, and December 31, 2017. The demographic and clinical characteristics of the patients were obtained from the register of patients treated for drug-resistant tuberculosis. The data were entered using EpiData version 4.2 and exported to Stata Version 14.1 for further analysis. Descriptive measures were used to characterize the study participants. Kaplan-Meier was used to estimate the survival time of the patients. Cox proportional hazard model was used to identify risk factors for mortality. Hazard Ratio (HR) with 95% confidence interval was used to report the strength of association between risk factors and mortality. RESULTS: Death was observed among 14.2% (n = 70) of the 498 patients who met the inclusion criteria. The incidence rate of death was 8.20 (95% CI: 7.62, 20.50) per 1000 Person-months in the course of follow-up. The median age was 29.30 years (IQR:23–41). Age 45 years and above (adjusted hazard ratio (AHR) = 1.28: 95% CI: 1.10, 1.68), smoking cigarette (AHR = 1.39: 95% CI:1.27,3.18), tuberculosis related complication (AHR = 9.31:95% CI:5.11,16.97), anemia (AHR = 3.04:95% CI:1.14, 9.20), HIV/AIDS (AHR = 1.34:95% CI:1.25, 3.35), previous tuberculosis treatment history (AHR = 1.37:95% CI:1.16, 1.86), and diabetes mellitus (AHR = 1.85:95% CI:1.24,5.71) were identified risk factors for mortality. CONCLUSIONS: This study concluded that drug-resistant tuberculosis mortality remains high in the study site. Age 45 years and above, smoking cigarette, tuberculosis related clinical complication, being anemic at baseline, HIV/AID, previous tuberculosis treatment history, and diabetes mellitus were identified risk factors for mortality. Continual support of the integration of TB/HIV service with emphasis and working on identified risk factors may help in reducing drug-resistant tuberculosis mortality.