The Impact of Elevated Hemoglobin A1C (HbA1c) and Related Comorbidities on Morbidity and Mortality of Patients Undergoing Coronary Artery Bypass Grafting

Objective: The objective of the study was to identify the impact of elevated hemoglobin A1C (HbA1c) and related co-morbidities on morbidity and mortality of patients undergoing coronary artery bypass grafting.

Methods: A total of 575 patients who underwent coronary artery bypass grafting (CABG) in the Department of Cardiothoracic and vascular surgery, King George's Medical University, Lucknow from June 2015 to July 2017, were enrolled and preoperative HbA1c levels were obtained. The Portland protocol for insulin was used to achieve tight glucose control of patients as part of an effort to reduce morbidity and mortality. The multivariate risk factors for operative morbidity and mortality were analyzed.

Results: In-hospital mortality was significantly higher for patients with HbA1c  7% and also the incidence of postoperative morbidities like wound infection, renal dysfunction and arrhythmias were significantly increased. These patients had more blood loss and received more blood products and had prolonged ventilatory time and spent more time in the hospital than patients with HbA1c less than 7%.

Conclusion: HbA1c may be a more accurate predictor of outcomes than merely a diagnosis of diabetes, with the added benefit of quantification of diabetes as a risk factor. The elevated HbA1c level was strongly associated with adverse events after coronary artery bypass grafting.