Aims/IntroductionDiabetes is a major risk factor for coronavirus disease 2019 (COVID‐19) severity. We aimed to retrospectively investigate the rates of patients with no diabetes, untreated diabetes, treated diabetes, COVID‐19‐related diabetes and the factors associated with bleeding complications in a cohort of patients with severe COVID‐19.Materials and MethodsThis was a multicenter, retrospective, observational study. Participants were COVID‐19 patients enrolled in the Cross‐sectional ICU Information Search System (CRISIS) from February 2020 to March 2022. Patients were classified into four groups according to diabetes status and treatment status. Hemorrhagic complications were defined as bleeding requiring transfusion of four or more red blood cell units, a drop of hemoglobin of ≥2 g in 24 h and retroperitoneal, airway or intracranial bleeding. Logistic regression analysis was carried out to examine factors associated with bleeding complications.ResultsA total of 1,076 patients were included in the analysis. The rates of patients in the no diabetes, untreated diabetes, treated diabetes and COVID‐19‐related diabetes groups were 17.4, 23.0, 23.9 and 35.7%, respectively. Bleeding complications were observed in 7.5% of all patients. Glycated hemoglobin level and renal failure were significantly correlated with bleeding complications (odds ratio 1.16, 95% confidence interval 1.02–1.33 and 2.77, 95% confidence interval 1.16–6.63, respectively). Patients with diabetes, including those with COVID‐19‐related diabetes, accounted for approximately 83% of all cases.ConclusionsIn patients with severe COVID‐19 with high glycated hemoglobin and renal failure, we recommend additional attention to the course of COVID‐19, given the risk of bleeding complications.