Background <p>Insulin resistance (IR) is closely associated with the development and recurrence of atrial fibrillation (AF). Several non-insulin-based surrogate markers of insulin resistance, including the triglyceride-glucose index (TyG), triglyceride-glucose-body mass index (TyG-BMI), metabolic score for insulin resistance (METS-IR), triglyceride-to-high-density lipoprotein cholesterol ratio (TG/HDL-C), estimated glucose disposal rate (eGDR), and C-reactive protein-triglyceride-glucose index (CTI), can be calculated from routine clinical biomarkers. However, the value of these indices in predicting recurrence after catheter ablation for AF remains unclear. In particular, CTI, a novel marker integrating inflammatory and metabolic status, has not been fully explored for its potential role in predicting post-ablation AF recurrence. This study aimed to systematically evaluate the association and predictive performance of six insulin resistance surrogate markers for AF recurrence after catheter ablation.</p> Methods <p>This retrospective two-center cohort study included 590 patients with nonvalvular AF who underwent first-time catheter ablation between January 2022 and March 2025. Six IR surrogate indices were calculated, and AF recurrence within 1 year was defined as the primary endpoint. Multivariable Cox regression, Kaplan-Meier analysis, restricted cubic spline (RCS) analysis, C-statistic, net reclassification improvement (NRI), and integrated discrimination improvement (IDI) were used to assess associations and predictive value.</p> Results <p>During 1-year follow-up, 167 patients experienced recurrence (28.31%). Multivariable Cox analysis showed that lower eGDR and higher TyG, TyG-BMI, METS-IR, and CTI were associated with increased recurrence risk, with more stable associations observed for eGDR, TyG-BMI, METS-IR, and CTI. Kaplan-Meier and RCS analyses further supported stratified differences and exposure-response relationships for some indices. For predictive performance, eGDR showed the most favorable overall performance, while CTI, TyG-BMI, and METS-IR also provided incremental predictive value. TyG and TG/HDL-C showed relatively limited incremental value. After false discovery rate correction, subgroup analyses showed generally consistent results.</p> Conclusion <p> Among the six IR surrogate indices, eGDR, CTI, TyG-BMI, and METS-IR were associated with AF recurrence after catheter ablation. eGDR showed the most favorable overall predictive performance. These indices may serve as adjunctive markers for post-ablation recurrence risk stratification, although prospective validation is needed.</p>