Association between triglyceride-glucose index and postoperative delirium following cardiac surgery: a multicenter retrospective analysis

BACKGROUND: Postoperative delirium (POD) after cardiac surgery correlates with adverse outcomes, increasing healthcare burdens and hindering patient recovery.The triglyceride-glucose (TyG) index, a marker of insulin resistance, shows cardiovascular prognostic value.This study sought to explore the association between the TyG index and the development of POD in patients undergoing cardiac surgery. METHODS: This multicenter retrospective cohort study included 1,850 patients (MIMIC-IV: n = 1,461; Yuhuangding: n = 389). A four-knot restricted cubic spline (RCS) regression analyzed the nonlinear relationship to determine the TyG threshold. Multivariable logistic regression and propensity score matching (PSM) controlled for baseline differences.Subgroup analyses were conducted. RESULTS: Patients with POD exhibited significantly higher TyG indices compared to non-POD patients (MIMIC-IV cohort: 9.06 vs. 8.83, P < 0.001). Using the optimal threshold derived from RCS regression, participants were stratified into two groups: Q1 (< 8.91) and Q2 (≥ 8.91). Multivariable logistic regression revealed that a TyG index ≥ 8.91 was independently associated with an increased risk of POD (adjusted OR 1.767, 95% CI: 1.406-2.219, P < 0.001). This association remained statistically significant in PSM-adjusted analyses across multiple regression models. These findings were validated in the Yuhuangding Hospital cohort. Subgroup analyses demonstrated significant interaction effects in specific patient populations. CONCLUSION: This study establishes a robust and independent association between an elevated TyG index and increased risk of POD in cardiac surgery patients, suggesting that the TyG index may serve as a valuable biomarker for identifying patients at risk of postoperative delirium.