The C-reactive protein-triglyceride-glucose index predicts new-onset atrial fibrillation after ST-segment elevation myocardial infarction.

Background: New-onset atrial fibrillation (NOAF) is a common complication following primary percutaneous coronary intervention (PCI) for ST-segment elevation myocardial infarction (STEMI), with a reported incidence of 6.3%-8.0%. It represents a significant risk factor for major adverse cardiovascular events (MACE) in this patient population. The C-reactive protein-triglyceride-glucose index (CTI), a composite biomarker reflecting both inflammatory (via high-sensitivity C-reactive protein, hs-CRP) and metabolic (via the triglyceride-glucose index, TyG index) pathways, has demonstrated prognostic potential for predicting MACE and mortality. Nevertheless, its specific utility in predicting NOAF among STEMI patients undergoing primary PCI has not been investigated. Methods: This retrospective study included 696 patients (mean age 63.9 ± 12.97 years) diagnosed with acute ST-elevation myocardial infarction. Clinical data were collected to calculate the TyG index = ln[TG(mg/dL) ×  FBG(mg/dL)/2] and the CTI = 0.412 × [CRP(mg/L)] + ln[(TG(mg/dL) × FBG(mg/dL))/2]. NOAF was defined as atrial fibrillation occurring for the first time within 30 days after primary PCI. Multivariate logistic regression was used to assess the association between CTI and NOAF. Receiver operating characteristic (ROC) analysis was used to evaluate the predictive value of the CTI, the TyG index and high-sensitivity hs-CRP, with area under the curve (AUC) differences being determined via DeLong's test. Results: Of 696 initially screened participants, 62 (8.9%) developed NOAF. Multivariate analysis (stepwise forward method) confirmed CTI, Age, LVEF, and IRA-RCA as independent predictors of post-primary PCI NOAF. In ROC analysis, the CTI demonstrated superior discriminative power for NOAF with an AUC of 0.741, compared to the TyG index (AUC = 0.686) and hs-CRP (AUC = 0.664), and the Delong test confirmed that these differences were statistically significant. Combining CTI with conventional clinical indicators further improved NOAF risk stratification (AUC = 0.795). Conclusions: CTI is an independent risk factor for post-primary PCI NOAF in STEMI patients. It exhibits superior predictive value for NOAF compared to hs-CRP or TyG index alone, making it a clinically useful tool for risk stratification in this patient population.