Abstract
Background Heart failure (HF) is a major global cause of morbidity and mortality. Reliable prognostic markers are essential for guiding long-term management. The Fibrosis-4 (FIB-4) and Fibrosis-5 (FIB-5) indices, initially developed for staging liver fibrosis, have recently been proposed as predictors of cardiovascular outcomes. However, their comparative value in heart failure with reduced ejection fraction (HFrEF) remains unclear. Objectives To assess and compare the prognostic performance of FIB-4 and FIB-5 in predicting long-term mortality in HFrEF patients. Methods This dual-center retrospective study included 593 patients hospitalized with HFrEF between January 2015 and December 2023. The primary endpoint was 5-year all-cause mortality; secondary endpoints included 1-year mortality and hospital readmission. FIB-4 and FIB-5 were calculated from admission laboratory values. Receiver operating characteristic (ROC) analyses and multivariable logistic regression were performed to determine prognostic value. Results Over a median follow-up of 5 years, all-cause mortality was XX%. Both FIB-4 and FIB-5 predicted long-term mortality (AUC: X.XX and X.XX, respectively). In patients aged ≤75 years, FIB-5 showed superior discrimination compared with FIB-4 (AUC 0.662 vs. 0.584, p<0.05). In multivariable analysis adjusted for clinical and echocardiographic variables including right ventricular dysfunction, FIB-5 remained an independent predictor of 5-year mortality (OR 1.05, 95% CI 1.01–1.10, p=0.04). Conclusion FIB-4 and FIB-5 are both associated with mortality in HFrEF. FIB-5 demonstrated greater prognostic strength and independence from right ventricular function, supporting its potential as a practical risk stratification tool.