To study the impact of poor glycemic control (Elevated HbA1c) on post-operative frequency of acute kidney injury after coronary artery bypass graft (CABG) surgery.

Abstract

Objective: To compare the frequency of acute kidney injury in diabetic patients with HbAlc ≥7% and HbA1c <7% undergoing CABG surgery and to determine the severity of AKI and adverse outcome in diabetic patients undergoing CABG surgery. Study Design: Comparative Cross-sectional study. Setting: The study was conducted in Cardiac Surgery Department, Faisalabad Institute of Cardiology, Faisalabad. Period: The duration of study was from 05/05/2023 to 04/05/2024. Methods: The present study involved 100 diabetic patients undergoing CABG surgery assimilated into two equal groups; Group-A (HbA1c ≥7.0%) and Group-B (HbA1c <7.0%). These patients were followed in the post-operative period and occurrence of AKI was noted along with its severity according to RIFLE criteria. These patients were managed as per department protocols and adverse outcome in the form of mortality was noted. Frequency of AKI, its severity and adverse outcome was compared between the groups. Results: The calculated mean age of the participants was 51.5 years, with a standard deviation of ±7.4 years. There was male predominance (M:F; 7.3:1). Following cardiac surgery, the mean of peak serum creatinine was significantly higher (1.25±0.36 vs. 1.03±0.24 mg/dl; p-value<0.001) while the mean glomerular filtration rate was significantly lower (66.14±21.17 vs. 75.96±17.52 mL/min/1.73m²; p-value=0.013) in patients with elevated HbA1c (≥7.0%). The frequency of post-operative AKI was significantly higher in patients with poor glycemic control (44.0% vs. 12.0%; p-value<0.001). Among the 28 patients having AKI, 15 (53.6%) patients were categorized as risk while 13 (46.4%) patients were categorized as injury under RIFLE criteria. Adverse outcome was noted in 4 (4.0%) patients. When compared the frequency of adverse outcome comparably higher in individuals with increased HbA1c ≥7.0% (8.0% vs. 0.0%; p-value=0.041) and AKI (14.3% vs. 0.0%; p-value=0.005). Conclusion: In diabetic patients undergoing CABG, poor preoperative glycemic control was identified as a key predictor of postoperative AKI and mortality. This emphasizes the importance of HbA1c in risk stratification and optimizing glycemic management for better patient outcomes.