Diabetes is not a risk factor for hospital mortality following contemporary coronary artery bypass grafting

The outcome of coronary artery bypass grafting (CABG) in diabetic patients has traditionally been worse than in non-diabetic patients. Recent studies have suggested an improvement in outcome in diabetic patients undergoing contemporary CABG. However, the direct impact of diabetes on mortality and morbidities following CABG remains unclear. We retrospectively analyzed prospectively collected data of 2725 CABG patients from January 1998 to December 2005: one thousand and eighty-five (40%) diabetics and 1640 (60%) non-diabetics [mean age 65+/-11 years, 1882 (69%) male]. Subgroup analysis was performed for two study periods (1998-2002 vs. 2003-2005). The overall hospital mortality was 1.8% [n=50; diabetics: 2.4%, non-diabetics: 1.5% (P=0.07)]. The mortality rate among diabetics decreased from 3.1% in 1998-2002 to 1.0% in 2003-2005 (P=0.021). Diabetes was not an independent predictor of hospital mortality but predicted the occurrence of deep sternal wound infection (OR=3.77). Diabetes significantly decreased long-term survival [1-year and 5-year survival 94.7+/-0.7% and 81.9+/-1.4% for diabetic vs. 95.4+/-0.5% and 85.9+/-1.0% for non-diabetic patients (P=0.01)]. Excellent results following contemporary CABG can be expected in diabetics with a similar mortality compared to non-diabetics. Therefore, our data suggest that diabetes may, in fact, not be a risk factor for adverse outcome following CABG. However, long-term survival in diabetics remains significantly inferior compared to non-diabetics.