The liver fibrosis‐8 index is a predictor for all‐cause mortality in cardiovascular disease patients: A cohort study

Abstract Aims Participants with cardiovascular diseases (CVD) often exhibit liver function abnormalities, hepatic fibrosis and cirrhosis. The extent of liver fibrosis is closely related to the prognosis of CVD. However, the association between the liver fibrosis‐8 (FIB‐8) index, a marker of liver fibrosis, and all‐cause mortality in CVD participants remains unclear. This study aims to investigate the relationship between the FIB‐8 index and all‐cause mortality among individuals with CVD. Materials and Methods A total of 1727 CVD American participants were enrolled from the National Health and Nutrition Examination Survey (NHANES) spanning from 1999 to 2018. Initially, we constructed weighted COX regression models and performed sensitivity analyses to examine the correlation between the FIB‐8 index and all‐cause mortality in CVD participants. Subsequently, we employed restricted cubic spline (RCS) to visualize their linear relationship. Finally, the stratified analyses and interaction tests of covariates were performed and presented in the forest plot. Results A total of 1727 participants were included in our study, with a mean age of 61.68 ± 0.47 years, with men accounting for 59.19%. After adjustment for relevant covariables, weighted COX regression models indicated that the hazard ratio (HR) and 95% confidence interval (95% CI) for the association between the FIB‐8 index and all‐cause mortality in CVD participants was 1.21 (1.12, 1.30). Sensitivity analysis was then conducted, revealing that the results remained stable. In fully adjusted model, individuals in quartiles 3 and 4 demonstrated significant statistical differences compared to the lowest FIB‐8 index quartile, with HR (95% CI) values of 1.88 (1.23, 2.87) and 2.17 (1.33, 3.53), respectively. Subsequently, RCS showed a linear relationship between the FIB‐8 index and all‐cause mortality among CVD participants. Finally, the interaction test revealed that no other covariables had significant interactions with the FIB‐8 index in this study. Conclusions A positive and linear correlation was observed between the FIB‐8 index and all‐cause mortality among CVD adult participants in NHANES from 1999 to 2018. Our findings indicated that the FIB‐8 index could serve as an excellent indicator for assessing all‐cause mortality within the CVD population. The lower the FIB‐8 index, the lower the all‐cause mortality among CVD participants.