Impact of hyperglycemia on perioperative mortality after coronary artery bypass graft surgery

Objective: The roles of perioperative hyperglycemia and diabetes in the risk stratification of patients undergoing coronary artery bypass graft surgery are unclear. The aim of this study is to explore the influence of perioperative hyperglycemia on postoperative mortality.

Method: A prospective, observational study of 5050 patients undergoing cardiopulmonary bypass for coronary artery bypass graft surgery at 70 international centers was conducted, with 7500 measured variables per patient and outcomes adjudicated centrally. Postoperative blood glucose levels measured from the day of surgery to postoperative day 3 were available for 4799 patients. Multivariable logistic regression was used to determine the association of hyperglycemia with hospital mortality.

Results: A total of 164 patients died during hospitalization (3.2%). Mortality was significantly higher in the diabetic population compared with the nondiabetic population (4.2% vs 2.9%; P = .02). In nondiabetic patients, maximum postoperative blood glucose between 250 and 300 mg/dL (adjusted odds ratio, 2.56; 95% confidence interval, 1.18-5.57; P = .02) and maximum blood glucose of 300 mg/dL or greater (adjusted odds ratio, 2.74; 95% confidence interval, 1.22-6.16; P = .01), compared with maximum blood glucose less than 200 mg/dL, and postoperative insulin treatment (adjusted odds ratio, 2.04; 95% confidence interval, 1.12-3.70), were independent risk factors for an increased risk of in-hospital mortality. In diabetic patients, hyperglycemia was not associated with a higher mortality risk.

Conclusions: Postoperative hyperglycemia is associated with increased in-hospital mortality in nondiabetic patients after coronary artery bypass graft surgery. In diabetic patients, hyperglycemia was not associated with mortality.