Which level of preoperative glycated haemoglobin (HbA1c) affect early morbidity and mortality after cardiac surgery?

BackgroundDiabetics account for 34 per cent of all patients undergoing coronary artery bypass graft (CABG) surgery, and have higher rates of postoperative mortality. Furthermore, they are at risk for ICU admission postoperatively due to complications of hyperglycaemia, which in turn increases hospital mortality.AimsThe purpose of this study was to evaluate the level of glycated haemoglobin (HbA1c) in patients undergoing cardiac surgery, and to establish it is an independent predictor for postoperative mortality and morbidity.Methods This retrospective study was conducted at King Fahd University Hospital. Files of 146 diabetic patients who underwent cardiac surgery in the period between September 2015 to June 2018 were included. One hundred and five patients met the inclusion criteria. Depending on the results of HbA1c preoperatively, patients were divided into 2 groups: Group A, with a HbA1c > =8.5 per cent, accounting for 33 patients, and Group B with a HbA1c < =8.4 per cent accounting for 71 patients.Results This study included 79 males and 25 females, with ages ranging in between 17 to 87 years old, with no significant difference between both groups in age and sex. A significant difference was found between Group A and Group B in postoperative mortality (p-value < 0.002). No significant difference was found when comparing length of hospital stay, wound infection postoperatively, reoperation, or readmission.ConclusionThere was a significant difference in mortality postoperativly between the two groups, with patients who had higher HbA1c levels experiencing higher mortality. Since our sample size was small, we recommend that further studies be done in multiple centres