Fibrosis‐4 index reflects the severity of tricuspid regurgitation and patient prognosis in atrial fibrillation

Abstract Aims Atrial fibrillation is a prevalent disease with increased risk of tricuspid regurgitation (TR), which can worsen prognosis by causing right heart remodelling. Fibrosis‐4 index (FIB‐4), a composite marker originally developed for liver fibrosis, has been revealed of prognostic value in heart failure. We aimed to clarify the association between FIB‐4 and the severity of TR as well as the prognosis. Methods and results We conducted a retrospective cohort study in a medical centre, identifying atrial fibrillation patients with complete biochemical and echocardiographic data for evaluation. Up to 4919 patients were included. The median age was 75 years, 60.0% ( n = 2952) of patients were male, 40.8% ( n = 2008) of patients had significant mitral regurgitation, 52.1% ( n = 2564) of patients had significant TR, and 34.4% ( n = 1691) had both. The median level of FIB‐4 was 2.33. Using multivariable regression, a positive correlation was observed between significant TR and FIB‐4. With a median follow‐up duration of 3.9 years, mortality occurred in 2694 (54.8%) patients. The high FIB‐4 group (>2.67) was associated with an increased risk of all‐cause death (adjusted hazard ratio [aHR] 1.357, 95% confidence interval [CI] 1.183–1.555, p < 0.001) when compared with the low FIB‐4 group (<1.3). In subgroup of isolated TR, high FIB‐4 was also associated with significantly higher risks of all‐cause mortality (aHR 1.930, 95% CI 1.330–2.801). Conclusions In patients with atrial fibrillation, FIB‐4 was positively associated with TR severity and an increased risk of all‐cause mortality. FIB‐4 serves as a simple, non‐invasive tool for prognostic stratification of TR and possible surrogate marker for timely intervention.