Incidence and predictors of diabetes mellitus among severe COVID-19 patients in western Ethiopia: a retrospective cohort study

Background: Evidence reported a high occurrence of diabetes mellitus (DM) during the time of COVID-19. This study aimed to assess the incidence of DM and its predictors among severe COVID-19 patients admitted to the treatment centre of Wollega University Referral Hospital (WURH), western Ethiopia. Methods: A facility-based retrospective cohort study was conducted among severe COVID-19 patients diagnosed using the rRT-PCR from September 30, 2020, to June 10, 2021. EpiData version 3.2 was used for data entry, and STATA version 14 for analysis. A Cox proportional hazard regression analysis was used to determine factors associated with DM. A multivariable Cox regression model with 95% CI and adjusted hazard ratio (AHR) was used to identify a significant predictor of the incidence of DM at p-value < 0.05. Results: A total of 304 patient cards with complete data were included in the final analysis. The mean age of the participants was 43.3 (SD ± 16.9) years. Of the total 304 patients admitted with severe COVID-19, 14.5% were newly diagnosed with DM with an overall incidence rate of 13.7 per 1 000 person days’ observation (PDO). The median time to occurrence of DM was 11 days (95% CI 7, 13) days. Age > 41 years (AHR = 2.54, 95% CI 1.15, 5.57), living in urban (AHR = 2.49, 95% CI 1.12, 5.52) and loss of appetite (AHR = 2.24, 95% CI 1.16, 4.34) increased the hazard of DM incidence, while presenting to the health facility after two days of clinical manifestation (AHR = 0.49, 95% CI 0.23, 0.96) decreased the risk of developing DM. Conclusions: The incidence rate of DM among patients admitted with severe COVID-19 in the study area was found to be 13.7 per 1 000 person days’ observation. Higher age, urban residence, early presentation to a health facility and loss of appetite were independent predictors of DM incidence. Therefore, we recommend early detection of DM and frequent monitoring of blood glucose for patients diagnosed with COVID-19.