Effect of glycaemic control on coronary artery bypass grafting outcomes - a United Kingdom centre experience.

Objectives: Assess whether pre-operative HbA_1c demonstrates positive predictive value relating to outcomes following coronary artery bypass grafting (CABG) in diabetes patients.

Methods: Retrospective analysis of outcomes and mortality following CABG; examining the effects of diabetes and HbA_1c.

Results: Post-operative length of stay (LOS) was prolonged in elective and urgent diabetes patients;7.3 ± 2.1 versus 6.4 ± 1.6 days and 9.0 ± 1.9 versus 7.6 ± 1.8 days, respectively; (p < 0.001). Sternal and leg wound infection rate was higher in elective diabetes group compared to no-diabetes group; 7% versus 3% (p < 0.01) and 3% versus 1% (p < 0.05), respectively. Pneumonia rate increased in elective and urgent diabetes patients; 19% versus 8% (p < 0.001) and 21% versus 15% (p < 0.05), respectively. Diabetes increased new-onset atrial fibrillation; 26% versus 14% (p < 0.001), and doubled blood transfusion rate; 28% versus 14% (p < 0.001) in elective patients; with similar findings in urgent patients. Long-term mortality was higher with diabetes compared to no-diabetes in elective patients; 15% versus 5%, (p < 0.001), and urgent patients; 10% versus 2%, (p < 0.001). Elevated HbA_1c showed significant positive predictive value relating to long-term mortality, and rates of pneumonia, blood transfusion, wound infection in elective and urgent diabetes patients; (p < 0.001). Elevated HbA_1c was an independent predictor of long-term mortality (hazard ratio:5.27, 95% CI:2.53-10.99; p < 0.001), superficial wound infection (odds ratio (OR):18.23, p < 0.001) and delayed discharge (OR:8.15, p < 0.001).

Conclusions: Diabetes patients have prolonged LOS and increased morbidity following CABG. HbA_1c is predictive of morbidity and long-term mortality in diabetes patients, and pre-operative HbA_1c screening is justified in all surgical patients.