Prognostic impact of diabetes mellitus on hospitalized COVID-19 patients: A large-scale retrospective cohort study from Türkiye

Background:This study examines the prognostic role of diabetes mellitus (DM) in predicting COVID-19 severity and fatal outcomes among hospitalized patients in Turkey. By evaluating a large cohort, we aim to delineate the relationship between DM and ICU utilization and to validate our findings against Turkish national data. Methods:This retrospective study analyzed 906 patients hospitalized with confirmed COVID-19 between 2020 and 2021. Patients were categorized into diabetic and non-diabetic groups. Age- and sex-matched analyses were conducted to isolate the effect of DM on ICU admission rates, oxygen requirements, length of stay (LOS), and in-hospital mortality. Results: Diabetic patients experienced significantly more severe illness compared to non-diabetics. They demonstrated markedly higher rates of ICU admission (OR=1.474, 95% CI: 1.038–2.094; p=0.030) and oxygen supplementation needs (p < 0.05). LOS was significantly longer in the diabetic group (p <0.05). While the mortality rate was clinically higher in diabetic patients (16.9% vs. 15.9%), the difference was not statistically significant. Advanced age (≥65 years), male sex, and hypertension were identified as primary predictors of severity. Conclusion: Our findings confirm that DM is a primary driver of COVID-19 severity and resource utilization in Turkey, consistent with the national 'TurCoviDia' study. The increased need for ICU care and respiratory support underscores the necessity for early clinical intervention and rigorous glycemic management to improve prognostic outcomes.