Methods: This project is a prospective observational study at the McGill University Health Center adult medical and surgical ICUs. HbA1c is measured at the admission to the ICU. The data are being collected prospectively using Microsoft access data entry. The following parameters will be recorded on admission: admitting diagnosis, sex, age, height, weight, body mass index (BMI), Acute Physiology and Chronic Health Evaluation (APACHE) II score, previous diagnosis of DM, whole blood HbA1c level, blood and plasma glucose levels. With power 80%, type I error 5% and with an expected 25% mortality difference between patients with HbA1c≥6.5 and <6.5, the required sample size is 1800 patients. The data will be presented as mean ± SD unless otherwise specified and statistical significance will be set as P < 0.05. All p-values presented will be 2-tailed.