The Impact of Diabetes on Early and Midterm Outcome of Patients Undergoing Coronary Artery Bypass Grafting Surgery

Background: Diabetic patients constitute about 25% of patients undergoing coronary artery bypass graft sur- gery (CABG). The impact of diabetes on the results of this operation, especially in Asian patients is not well understood. The present study aims to evaluate the effect of this important risk factor on the early and midterm outcome following CABG. Methods: This study was performed in Shahid Madani Heart Hospital, Tabriz, Iran from April 1998 to April 2003. Considering our inclusion and exclusion criteria, 1269 patients available for follow up were enrolled and evaluated for their early (30 days) and midterm mortality. Results: Diabetic patients constituted 332 (26.2%) of our patients. Female gender, hypertension, hyperlipid- emia and peripheral arterial disease (PAD) were more prevalent in diabetics. Early mortality was not signifi- cantly different between two groups (6.6% in diabetics vs. 5% in non-diabetics, P=0.300) and this was true for early cardiac death (6.3% in diabetics vs. 4.7% in nondiabetics, P=0.200). However, in midterm follow up of 4.1 ± 1.6 years, diabetic patients had significantly higher mortality (18.7% in diabetics vs. 11.2% in non- diabetics, P<0.001). Also total mortality was significantly higher in diabetics (25.3% in diabetics vs. 16.2% in non-diabetics, P<0.001). In univariate regression analyses diabetes was an independent risk factor for midterm mortality. Conclusion: Diabetes may not be an independent risk factor for early death following CABG. However, it is an important predictor of midterm mortality.