The prevalence of elevated hemoglobin A1c in patients undergoing coronary artery bypass surgery

Background: Diabetes mellitus has become a major health issue in the United States and contributes to morbidity and mortality from coronary artery disease. Despite lifestyle changes and medications that have been shown to decrease complications and death, many persons have poor glycemic control. The purpose of this study is to determine the prevalence of elevated Hemoglobin A1c levels, a marker of glycemic control in patients presenting for coronary artery bypass surgery, and to determine if risk factors for diabetes mellitus could identify those patients with an elevated hemoglobin A1c. Methods: All patients undergoing coronary artery bypass surgery had hemoglobin A1c levels determined immediately preoperatively. Proportions were used to describe the number of patients with elevated levels. Linear regression and receiver operator characteristic curves were used to evaluate the accuracy of risk factors to identify patients with elevated levels. Results: 83 of 87 (95%) diabetic patients had elevated A1c levels (>= 6.0%), with 55 of 87 (63%) having inadequate control - A1c levels >= 7.0. 93 of 163 (57%) non-diabetic patients had elevated A1c levels (>= 6.0%), with 19 (12%) having levels >= 7.0%. Risk factors for diabetes mellitus poorly predicted which patient had elevated A1c levels. Conclusion: The prevalence of elevated hemoglobin levels in patients undergoing coronary artery bypass surgery is high and routine measurement should be done to permit institution of lifestyle modifications and medication changes that decrease complications and death from diabetes mellitus.