Hepatic metabolic burden and all-cause mortality across glucose metabolism statuses in a cardiovascular-kidney-metabolic syndrome population: insights from the National Health and Nutrition Examination Survey (NHANES)

BACKGROUND: Hepatic metabolic burden is an integral component of cardiometabolic risk. However, the association of hepatic metabolic burden assessed by the fatty liver index (FLI) with all-cause mortality in cardiovascular-kidney-metabolic (CKM) syndrome has not been well described when individuals are stratified by glucose metabolism status. Therefore, this study aimed to evaluate the association between FLI and all-cause mortality across different glucose metabolism states in adults with CKM syndrome. METHODS: Data were derived from the National Health and Nutrition Examination Survey (NHANES) 1999-2018. Adults with CKM syndrome according to the AHA/ADA framework were included and categorized by glucose metabolism status as normoglycemia, prediabetes, or diabetes. Hepatic metabolic burden was assessed using FLI. Weighted multivariable Cox proportional hazards models and restricted cubic spline (RCS) analyses were applied to examine the associations between FLI and all-cause mortality across glucose metabolism status. Additionally, joint analyses with combined FLI (FLI ≥ 60 vs.