Impact of diabetes mellitus on outcomes in Japanese patients undergoing coronary artery bypass grafting.

Background And Purpose: There have been no large-scale studies on the impact of diabetes mellitus (DM) on outcomes in Japanese patients undergoing coronary artery bypass grafting (CABG).

Methods And Subjects: A multi-institutional retrospective cohort study was conducted in 14 Japanese centers. All adult patients who underwent isolated CABG from 2007 to 2008 were included (n=1522, mean age: 68.5years). The definitions of DM were all patients admitted with diagnosis of DM and preoperative glycated hemoglobin (Hb) A1c≥6.5%. Univariate and multivariate analyses were performed to identify the risk of morbidity and mortality.

Results: There were 849 DM and 572 non-DM patients. Preoperative mean HbA1c were 7.1% in the DM group and 5.7% in the non-DM group (p<0.0001). Preoperative, intraoperative, and 3-day average postoperative blood glucose (BG) were 146mg/dl, 172mg/dl, and 168mg/dl in the DM group, and 103mg/dl, 140mg/dl, and 136mg/dl in the non-DM group (all p<0.0001). Although there were no significant differences in postoperative cardiovascular events, the incidence of infection was significantly higher in the DM group than in the non-DM group (9.2% vs 6.1%, p=0.036) on the univariate analysis. The all-cause death was also relatively higher in the DM group than in the non-DM group (2.1% vs 1.1%, p=0.12), and this was likely related to infection.

Conclusion: DM patients had worse perioperative BG control, higher incidence of infection, and higher mortality than non-DM patients. These results indicate that perioperative BG control guidelines should be standardized to obtain better surgical outcomes in Japanese DM patients.