Predictors of extrapulmonary tuberculosis among diabetic patients at Debre Markos compressive specialized hospital, Ethiopia, 2021: A retrospective cohort study

BACKGROUND: Extrapulmonary tuberculosis is an emerging public health problem among diabetic patients. Diabetes, which causes immunosuppression, is increasingly being recognized as an independent risk factor for tuberculosis, and the two often coexist and impact each other. Therefore, this study aimed to investigate the incidence and predictors of extra pulmonary 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 compressive specialized hospital between January 2016 to December 2020. All eligible diabetic patients who full filled the inclusion criteria were included in the study. Data were entered using Epi-data Version 3.1 and analyzed using STATA Version 14. The survival time of diabetic patients was estimated using the Kaplan-Meier survival curve, and the survival time between different categorical variables was compared using the log rank test. Both bi-variable and multivariable Cox-proportional hazard regression models were fitted to identify independent predictors of tuberculosis among diabetic patients. RESULTS: Among a cohort of 433 diabetic patients at Debre Markos compressive specialized hospital, 17(3.9%) developed extra pulmonary tuberculosis during the follow-up time. The total time allotted to follow up the study participants was 1101.5 person-years (PY). The overall extra pulmonary tuberculosis incidence rate was 1.5 per 100 PY with 95% CI. Using the multivariable Cox-regression analysis, age (AIR 4.8 (95% CI (1.2–20.7), 0.03), diabetic medication (AIR 1.4 (95% CI(1.24–16), 0.03), having past history of PTB before diabetic follow up initiation (AID 1.5(95% CI (3.2–6.9),0.01) and having history of alcohol (AIR (95%CI (4(1.2–13),0.02) were significantly increased the risk of extra pulmonary tuberculosis while BMI (18.5–25) AIR(95% CI (0.22 (0.06–0.76), 0.02) was associated with a rate reduction for the incidence of extra pulmonary tuberculosis. CONCLUSIONS: In this study, we found a high rate of extra pulmonary tuberculosis among diabetic patients. Factors significantly linked with increased risk of extra pulmonary tuberculosis included: age, using insulin as hypoglycemic medication, having past history of PTB before diabetic follow up initiation and alcoholic history while BMI was associated with a rate reduction of EPTB. Early screening and treatment for extra pulmonary tuberculosis is highly recommended at diabetes mellitus follow up for patients with the above risk factors.