Time to develop tuberculosis and its predictors among adult diabetes mellitus patients on follow-up at chronic outpatient department of hospitals in Southwest Shewa Zone, Oromia, Ethiopia: A retrospective cohort study

Abstract

Background: Diabetes mullites (DM) is a risk factor of tuberculosis (TB) and the two are often coexist and influence each other. Developing countries are suffering from DM which further exposes individuals to active TB infection. However, there is limited evidence on the time to develop TB and its predictors among adult diabetes mullites (DM) patients on treatment. Thus, this study aimed to determine time to develop TB and its predictors among adult DM patients on follow-up in hospitals in Southwest Shewa zone, Oromia Regional State, Ethiopia.

Methods: A retrospective cohort study was conducted among 346 DM patients on follow-up in hospitals found in Southwest Shewa Zone from 2013-2022. A systematic random sampling method was used to select the participants. A structured questionnaire and data extraction checklist were used to collect data. Descriptive statistics were used to summarize the characteristics of the participants. Kaplan-Meir curve was employed to show survival probability between groups for significantly associated variables. Cox-proportional hazard model was used to determine predictors of time to TB develop.

Results: Of the total 346 DM patients, 11.5% were developed TB during follow-up period, and more than 55% of TB incidences occurred within five years of follow-up. The overall TB incidence density was 2.2 per 100 (95% CI: (1.5–4.6)) person-year observations (PYOs). Age older than 50 year (AHR = 6.0, 95%CI:1.6–21.6), having smoking history (AHR = 5.8, 95%CI: 1.1–13.7), previous TB treatment history (AHR = 5.2, 95% CI: 2.2–2.6), being HIV sero-reactive (AHR = 3.5, 95% CI:1.6–8.2), being alcohol user (AHR = 3.5, 95% CI:1.6–7.6) and forgetfulness (AHR = 2.4, 95% CI: 1.2–4.9) were significantly predicted time to develop TB.

Conclusion: The incidence of TB in DM patients was considerable (11.5%), and more than 55% of TB incidences occurred within five years of follow-up. Interventions that targeted DM patients who smoke cigarette, drink alcohol, and have forgetfulness are vital to increase time to develop TB in DM patients.