Elevated glycosylated haemoglobin (HbA1c) is a risk marker in coronary artery bypass surgery

Objective. To evaluate if glycosylated haemoglobin 1 (HbA1c) was associated with increased risk of infection and mortality after coronary artery bypass grafting (CABG). Design. Prospective observational study. Preoperative HbA1c concentrations were correlated to outcome in patients followed for an average of 3.5 years after CABG. Results. HbA1c was ≥6% in 68% of 161 patients with diabetes mellitus (DM) and in 3% of 444 patients without DM. Superficial sternal wound infection was observed in 13.9% if HbA1c ≥6% versus in 5.5% if <6% (p=0.007). Mediastinitis occurred in 4.9% if HbA1c≥6% and in 2.1% if HbA1c<6% (p=0.20) (Hazard ratio (HR) 1.9, 95% CI 0.6-5.9). Follow-up mortality was 18.9% in patients with HbA1c≥6% compared to 4.1% if HbA1c<6% (p<0.001) with HR 5.4, (95% CI 3.0-10.0) after multivariable adjustment. The risk of death was similar regardless of DM diagnosis. Conclusions. HbA1c ≥6% was associated with an increased risk of postoperative superficial sternal wound infections and a trend for higher m...