Incremental value of insulin resistance surrogate indices beyond the CHA2DS2-VASc score for predicting thromboembolic events in patients with chronic heart failure and atrial fibrillation.

BACKGROUND

Patients with chronic heart failure (CHF) and atrial fibrillation (AF) are at high risk of thromboembolic events. Although the CHA2DS2-VASc score is widely used for risk stratification, it may not fully capture metabolic dysfunction. Whether insulin resistance (IR) surrogate indices provide incremental information beyond the CHA2DS2-VASc score in patients with CHF and AF remains unclear.

METHODS

This retrospective cohort study included 4,474 patients with CHF and AF. IR surrogate indices were calculated, and thromboembolic events were defined as ischemic stroke or systemic embolism (IS/SE). Multivariable Cox regression models assessed the associations between these indices and thromboembolic risk. Their incremental value beyond the CHA2DS2-VASc score for 4-year IS/SE risk was evaluated using discrimination, reclassification, and clinical utility measures, with stratification by AF type.

RESULTS

During a median follow-up of 4.00 years, 349 IS/SE events occurred. After multivariable adjustment, the hazard ratios per 1-SD increase were 1.27 (95% confidence interval, 1.13-1.43) for the TyG index, 1.41 (1.28-1.56) for the TyG-BMI index, 1.27 (1.20-1.34) for METS-IR, and 1.13 (1.08-1.19) for the TG/HDL-C ratio (all P < 0.001). Risk increased progressively across tertiles of each index, and the associations remained consistent in competing-risk analyses. Adding METS-IR or the TyG-BMI index to the CHA2DS2-VASc score significantly increased the AUC from 0.637 to 0.682 and 0.673, respectively, and improved reclassification. Decision curve analysis showed greater net benefit for models incorporating IR surrogate indices, particularly METS-IR and the TyG-BMI index. The incremental predictive improvements appeared more evident in patients with non-paroxysmal AF.

CONCLUSIONS

IR surrogate indices were independently associated with IS/SE in patients with CHF and AF. METS-IR and the TyG-BMI index provided the most consistent incremental information beyond the CHA2DS2-VASc score, with more evident improvements observed in patients with non-paroxysmal AF.