Inclusion Criteria:  All diabetic patients admitted to ICU of internal medicine department from October 2020 to November 2021 by heart failure  Exclusion Criteria:  Age ≤18 years.  Hypoglycemia (plasma glucose <70 mg/dL) at initial presentation. An admission diagnosis of diabetic ketoacidosis or hyperosmolar hyperglycemic state. Patients with hemoglobin variants (e.g., sickle cell anemia, thalassemia) or with hematologic conditions (e.g., hemolytic anemia) that could interfere with the accuracy of the HbA1c assay.