Objective: This study sought to determine whether aggressive glycemic control (90-120 mg/dL) would result in more optimal clinical outcomes and less morbidity than moderate glycemic control (120-180 mg/dL) in diabetic patients undergoing coronary artery bypass graft (CABG) surgery.
Summary of background data: Maintaining serum glucose levels between 120 and 180 mg/dL with continuous insulin infusions decreases morbidity in diabetic patients undergoing CABG surgery. Studies in surgical patients requiring prolonged ventilation suggest that aggressive glycemic control (<120 mg/dL) may improve survival; however, its effect in diabetic CABG patients is unknown.
Methods: Eighty-two diabetic patients undergoing CABG were prospectively randomized to aggressive glycemic control (90-120 mg/dL) or moderate glycemic control (120-180 mg/dL) using continuous intravenous insulin solutions (100 units regular insulin in 100 mL: normal saline) beginning at the induction of anesthesia and continuing for 18 hours after CABG. Primary end points were the incidence of major adverse events (major adverse events = 30-day mortality, myocardial infarction, neurologic events, deep sternal infections, and atrial fibrillation), the level of serum glucose, and the incidence of hypoglycemic events.
Results: There were no differences in the incidence of major adverse events between the groups (17 moderate vs 15 aggressive; P = 0.91). Patients with aggressive control had a lower mean glucose at the end of 18 hours of insulin infusion (135 ± 12 mg/dL moderate vs 103 ± 17 mg/dL aggressive; P < 0.0001). Patients with aggressive control had a higher incidence of hypoglycemic events (4 vs 30; P < 0.0001).
Conclusions: In diabetic patients undergoing CABG surgery, aggressive glycemic control increases the incidence of hypoglycemic events and does not result in any significant improvement in clinical outcomes that can be achieved with moderate control. Clinical Trials.gov (ID #NCT00460499).