Elevated triglyceride glucose index is associated with increased risk of postoperative acute kidney injury in coronary artery bypass graft patients: a multicenter cohort analysis

Objectives: The triglyceride glucose index (TyG) is commonly used to assess insulin resistance and has been linked to the prognosis of coronary atherosclerotic heart disease and related complications in diabetic patients. Nevertheless, the potential association of this index with postoperative acute kidney injury (AKI) following coronary artery bypass grafting (CABG) has yet to be clarified. Methods: This multicenter retrospective cohort study included 5427 patients who underwent isolated CABG and were recruited from six distinct cardiac centers, focusing on postoperative AKI. Preoperative serum creatinine levels were assessed, and renal function was continuously monitored over a 7-day postoperative period. The TyG index was calculated utilizing the initial fasting measurements of triglyceride and plasma glucose (PG) levels collected at the time of admission. Baseline demographic and clinical variables were obtained from the hospital information system. Patients were divided into quartiles based on their TyG index to assess the link between TyG levels and postoperative AKI. Results: Analysis showed significant differences in clinical and biological parameters among CABG patients based on TyG index quartiles ( P < 0.05). Logistic regression indicated a strong link between the TyG index and post-CABG AKI risk odds ratio (OR): 1.249; 95% confidence interval (CI), 1.105–1.411; P < 0.001, with the highest quartile (T4) having a notably higher risk compared to the lowest quartile (T1) (OR: 1.571; 95% CI, 1.247–1.981; P < 0.001). This association was especially significant in insulin-treated diabetic patients, who had the highest OR among all subgroups (OR: 3.982; 95% CI, 1.493–10.618; P = 0.006). Conclusions: This multicenter cohort study shows that the TyG index is strongly associated with postoperative AKI after CABG. Higher preoperative TyG levels effectively identify patients at elevated AKI risk, including those with diabetes – especially insulin-treated individuals. As a simple metabolic biomarker, the TyG index may help refine perioperative risk stratification and guide early preventive strategies in patients undergoing CABG.