 In a previous study, we showed that tight blood glucose control with insulin during intensive care reduced morbidity and mortality of surgical intensive care patients. Whether this intervention also improves prognosis of medical intensive care patients remains unknown. The current prospective, randomized, controlled study will assess the impact of intensive insulin therapy on the outcome of patients in a medical intensive care unit. On admission, patients will be randomly assigned to either strict normalization of blood glucose 80-110 mgdl with intensive insulin therapy or the conventional approach, in which insulin infusion is initiated only when blood glucose exceeds 215 mgdl, to maintain blood glucose levels between 180 and 200 mgdl. 