Association between triglyceride glucose-body mass index and postoperative atrial fibrillation (POAF) in patients undergoing coronary artery bypass grafting (CABG): a retrospective study

Background Postoperative atrial fibrillation (POAF) is a common complication after off-pump coronary artery bypass grafting (OPCABG), affecting 20–40% of patients. Insulin resistance (IR) may contribute to POAF pathogenesis, as obesity and metabolic syndrome are independent AF risk factors. IR-related markers such as the triglyceride-glucose index (TyG), triglyceride glucose-body mass index (TyG-BMI), and atherogenic index of plasma (AIP) have shown predictive value for cardiovascular events. However, their utility for POAF prediction in OPCABG remains unclear. We aimed to evaluate the predictive value of these IR indices for POAF in OPCABG patients and to develop a risk model incorporating these indices for improved risk stratification. Methods We retrospectively studied 757 adult patients undergoing isolated OPCABG at a single center (December 2020–June 2022). Whether IR indexes could predict POAF after OPCABG was investigated. Results Of 757 patients, 205 (27.08%) developed POAF. In logistic regression, higher TyG and TyG-BMI were independently associated with greater POAF risk after full adjustment. RCS analysis demonstrated a nearly linear increase in POAF risk with higher TyG, and a J-shaped relationship for TyG-BMI. AIP showed an almost linear, monotonic risk increase without a clear threshold. Incorporating these IR indices into the clinical baseline model significantly improved predictive performance, as evidenced by statistically significant improvements in both continuous net reclassification (NRI) and integrated discrimination (IDI). Predictive gains were most pronounced in patients with diabetes mellitus. The incremental value of IR indices was also evident in patients ≥65 years and in males. Conclusion Preoperative IR indices—especially TyG and TyG-BMI—are independent predictors of POAF in OPCABG patients. TyG index and TyG-BMI index also improve POAF risk stratification, particularly in patients with type 2 diabetes.