Contemporary Outcomes of Coronary Artery Bypass Grafting Among Patients With Insulin-Treated and Non–Insulin-Treated Diabetes

Background More than 40% of patients undergoing coronary artery bypass grafting (CABG) have diabetes. However, it is unknown how insulin treatment status influences cardiac surgical outcomes among patients with diabetes. Methods All isolated CABG, CABG plus aortic valve replacement or plus mitral valve repair/replacement procedures performed in 2012 were extracted from the California CABG Outcomes Reporting Program database. Patients were grouped into three categories: (1) no diabetes, (2) non–insulin-treated diabetes (NITDM), and (3) insulin-treated diabetes (ITDM). Demographic and clinical baseline characteristics and observed postoperative major adverse events, including 30-day mortality, stroke, deep sternal wound infection, prolonged ventilation, new dialysis requirement, renal failure, and 30-day readmission were compared. Multivariable logistic regression models were developed for predicting the impact of NITDM and ITDM on postoperative major adverse events. Results A total of 14,051 patients underwent isolated CABG or CABG plus aortic/mitral valve procedures in California during 2012; 6700 (47.7%) had no diabetes, 5165 (36.8%) had NITDM, and 2183 (15.6%) had ITDM. Compared with the nondiabetic and NITDM groups, the ITDM group was younger, more frequently women and nonwhite, and had a higher prevalence of preoperative comorbidities (all p < 0.05). After adjusting for baseline risk factors and surgery type compared with patients without diabetes, both NITDM and ITDM were associated with significantly increased risk of major adverse events [NITDM: adjusted odds ratio (AOR), 1.15, 95 % confidence interval (CI), 1.04 to 1.26, p = 0.005; ITDM: AOR, 1.49, 95% CI, 1.32 to 1.68, p < 0.0001]. A subgroup comparison indicated a similar gradient of risk for each category of cardiac surgery. Conclusions Patients with diabetes undergoing CABG have substantially increased risk of major adverse events. Patients with ITDM represent an especially high-risk group.