['To investigate the influence of diabetes mellitus on the hemodynamic-stabilizing effect of clonidine during off-pump coronary artery bypass (OPCAB) surgery.', 'Prospective study.', 'Public, university-affiliated hospital.', '40 patients (32 male, 8 female) scheduled for OPCAB surgery.', 'Patients were divided into equal groups of diabetic and nondiabetic patients. All patients were given 150 microg oral clonidine 1 hour before induction. Anesthesia was induced and maintained with fentanyl, propofol, and sevoflurane. Propranolol was administered intermittently to maintain an adequate heart rate (HR; 50 to 70 bpm). Preoperative demographic data (fasting blood glucose concentration and hemoglobin A1c), dose of intraoperative drugs (propofol and propranolol), and outcome data (duration of intubation and duration of hospital stay after surgery) were analyzed.', 'In the diabetic and nondiabetic groups, the mean (+/-SD) plasma glucose values were 7.8 +/- 2.3 mmoL. L(-1) and 5.4 +/- 0.7 mmoL. L(-1), respectively (p < 0.05), and the mean (+/-SD) HbA1c values were 7.1 +/- 1.3% and 5.2 +/- 0.4%, respectively (p < 0.05). The mean propofol infusion rate was 2.8 +/- 0.9 mg. kg(-1). h(-1) in diabetic patients and 3.1 +/- 1.0 mg. kg(-1). h(-1) in nondiabetics (NS, p > 0.05). The total requirement for propranolol was 5.1 +/- 2.4 mg in diabetic patients and 1.6 +/- 1.1 mg in nondiabetics (p < 0.05).'] Does diabetes attenuate the hemodynamic stabilizing effects of oral clonidine during off-pump coronary artery bypass surgery?