OBJECTIVE -To determine if glucose management in postcardiothoracic surgery patients with a combined intravenous (IV) and subcutaneous (SC) insulin regimen reduces mortality and morbidity in patients with diabetes and stress-induced hyperglycemia.RESEARCH DESIGN AND METHODS -Retrospective review of 614 consecutive patients who underwent cardiothoracic (CT) surgery in 2005 was performed to evaluate the incidence and treatment of postoperative hyperglycemia and operative morbidity and mortality. Hyperglycemic patients (glucose Ͼ6.05 mmol/l) were treated with IV insulin in the intensive care unit (ICU) followed by SC insulin (outside ICU). Subgroup analysis was performed on 159 coronary artery bypass grafting (CABG)-only patients.RESULTS -Among all CT surgeries, patients with a preoperative diagnosis of diabetes had higher rates of postoperative mortality (7.3 vs. 3.3%; P ϭ 0.03) and pulmonary complications (19.5 vs. 11.6%; P ϭ 0.02) but had similar rates of infections and cardiac, renal, and neurological complications on univariate analysis. However, on multivariate analysis, a preoperative diagnosis of diabetes was not a significant factor in postoperative mortality or pulmonary complications. In CABG-only patients, no significant differences were seen in outcomes between diabetic and nondiabetic patients. Independent of diabetic status, glucose Ն11 mmol/l on ICU admission was predictive of higher rates of mortality and renal, pulmonary, and cardiac postoperative complications.CONCLUSIONS -A combination of IV insulin (in the ICU) and SC insulin (outside the ICU), a less costly and less nursing-intensive therapy than 3 days of IV insulin postoperatively, results in a reduction of the increased surgical morbidity and mortality in diabetic patients after CT surgery. Diabetes Care 30:823-828, 2007