Association Between the Preoperative Triglyceride-Glucose Index and Acute Kidney Injury in Patients With Chronic Kidney Disease Undergoing Cardiac Surgery

Background: Acute kidney injury (AKI) is a major complication of cardiac surgery, particularly in patients with pre-existing chronic kidney disease (CKD), who are at higher risk due to their compromised renal function. This study investigated the association between the triglyceride-glucose (TyG) index, a marker of insulin resistance, and postoperative AKI in CKD patients undergoing cardiac surgery to enhance risk stratification and perioperative management.Methods: This retrospective study included 542 patients with impaired renal function (estimated glomerular filtration rate (eGFR) 15-60 mL/min/1.73 m2) undergoing cardiac surgery from January 2018 to December 2019. The TyG index was calculated as Ln(fasting triglycerides [mg/dL] x fasting blood glucose [mg/dL]/2), and outcomes were defined as postoperative AKI (per Kidney Disease: Improving Global Outcomes (KDIGO) criteria), in-hospital mortality, and length of hospital stay. Multivariate logistic regression and subgroup analyses assessed the association between TyG and these endpoints.Results: Among the 542 patients, 55.7% developed AKI, and the in-hospital mortality rate was 7.6%. In the multivariate regression analysis, the odds ratio for AKI with each unit increase in LnTyG was 0.43 (95% CI 0.02-8.70, p = 0.579), while in the standardized TyG, it was 0.96 (95% CI 0.77-1.21, p = 0.754). Subgroup analyses, stratified by age, sex, CKD stage, and diabetes status, revealed no significant associations across all strata (all p for interaction > 0.05).Conclusion: The TyG index is not significantly associated with AKI or prognosis after cardiac surgery in patients with kidney dysfunction. Further studies are needed to elucidate the role of insulin resistance in the pathogenesis of AKI.