['To investigate whether preinduction glucose is an important predictor for perioperative insulin management in patients undergoing cardiac surgery.', 'Prospective cohort study.', 'Large community hospital.', '80 consecutive patients scheduled for cardiac surgery.', 'Patients were subdivided into those with a preinduction blood glucose of 110 mg/dL or lower with or without history of diabetes (group 1) and those with a preinduction blood glucose of above 110 mg/dL with or without history of diabetes (group 2). In group 1, there were no known diabetics. In group 2, 31% (11/35) had diabetes (group 2DM), while 24/35 (69%) did not (group 2NDM). An insulin infusion was started intraoperatively and adjusted according to a strict protocol in order to maintain normoglycemia (80-110 mg/dL) until discharge from intensive care.', 'In patients with preinduction glucose above 110 mg/dL, whether or not previously treated for diabetes, perioperative insulin requirements were higher, and intraoperative insulin management was more difficult than in those with lower preinduction glucose. In patients with a preinduction glucose above 110 mg/dL, hospital stay was longer, and inhospital mortality was significantly higher than in those with lower preinduction glucose. Multivariate analyses showed that preinduction glycemia was a good predictor of intraoperative insulin consumption, as was the body mass index (BMI) for intensive care and total insulin needs.'] Are preinduction glycemia and body mass index important predictors of perioperative insulin management in patients undergoing cardiac surgery?