Incidence and Predictors of Tuberculosis among Adult Diabetic Patients, Debre Markos Referral Hospital, Northwest Ethiopia, 2018: A Retrospective Cohort Study

BACKGROUND: Tuberculosis remains a serious global public health problem. It mainly affects the lungs, and occurs in every part of the world. The link between tuberculosis and diabetes mellitus is essential to inform programs and policies, yet there is a scarcity of information in our study area. Therefore, this study aimed to investigate the incidence and predictors of tuberculosis among diabetic patients at Debre Markos Referral Hospital, northwest Ethiopia. METHODS: This institutionally based retrospective cohort study was undertaken among 433 diabetic patients of Debre Markos Referral Hospital between January 2013 and December 2017. All eligible diabetic patients who met the inclusion criteria were included in the study. Data were entered using EpiData version 3.1 and analyzed using Stata version 14. The survival time of diabetic patients was estimated using Kaplan–Meier survival curves, and survival time among different categorical variables compared using the log-rank test. Both bivariate and multivariate Coxproportional-hazard regression models were fitted to identify independent predictors of tuberculosis among diabetic patients. RESULTS: Among the cohort of 43326 (6%) developed tuberculosis during follow-up. The overall tuberculosis-incidence rate was 2.4 per 100 with 95% CI. The total time allotted to follow up the study participants was 1,101.5 person-years. Using multivariate Cox regression analysis, history of alcohol consumption (adjusted incidence ratio 4, 95% CI 1.2–13; P=0.02) and history of tuberculosis (12, 95% CI 3–39; P=0.01) significantly increased the risk of tuberculosis, but normal body-mass index and above (≥18.5 kg/m(2)) was associated with a rate reduction (0.34, 95% CI 0.14; P=0.80; 0.03) forincidence of tuberculosis. CONCLUSION: In this study, we found a high rate of tuberculosis among diabetic patients. Factors significantly linked with increased risk of tuberculosis included history of alcohol consumption, history of tuberculosis, and low body-mass index. Early screening and treatment for tuberculosis is highly recommended at diabetes mellitus follow-up for patients with these risk factors.