The influence of type 2 diabetes mellitus in patients undergoing coronary artery bypass graft surgery: an 8-year prospective cohort study

Abstract

Objective: To prospectively assess whether there are any outcome differences between patients with and without type 2 diabetes mellitus undergoing coronary artery bypass graft (CABG) surgery.

Study design: This was an 8-year, prospective hospitalization cohort study. Data were collected on 225 variables concurrently with hospital admission. The main outcome was total operative mortality. In addition, we evaluated 12 morbidity outcomes. To minimize confounding, we controlled for 16 other variables.

Results: A total of 6,711 patients were available for our analysis (diabetic patients, 2,178; and nondiabetic patients, 4,533). The diabetic patients were significantly more likely to be women, to have more left ventricular hypertrophy, to have a history of cerebrovascular disease, hypertension, and COPD, to have a greater body surface area, to have higher creatinine levels, to be African-American, to have undergone more elective procedures, to have a shorter pump time, and to have less of a history of tobacco use compared to nondiabetic patients (p < 0.05). Multiple regression analysis found no significant difference between the two groups for all 12 morbidity outcomes of interest. Diabetic patients experienced significantly more mortality than nondiabetic patients (relative risk, 1.67; 95% confidence interval, 1.20 to 2.30; p < 0.004).

Conclusion: Patients with type 2 diabetes who are undergoing CABG surgery experience significantly more total operative mortality compared to nondiabetic patients, even after controlling for multiple variables. There was no difference between the groups for 12 morbidity outcomes.