Association of serum fibroblast growth factor 21 levels with skeletal muscle mass and mortality in chronic hemodialysis patients.

BACKGROUND/PURPOSE: Fibroblast growth factor 21 (FGF21) is a hormone that modulates metabolic pathways, which acts as a myokine under metabolic stress. We aimed to explore the association of serum FGF21 levels with skeletal muscle mass and mortality in patients on hemodialysis (HD). METHODS: Baseline serum FGF21 levels were measured, and a portable whole-body bioelectrical impedance device was used to assess skeletal muscle mass. One hundred twenty-four patients undergoing chronic HD were categorized into high- and low-FGF21 groups according to the median FGF21 value. RESULTS: Patients with low FGF21 values had lower body weight, body mass index, skeletal muscle mass index (SMI = skeletal muscle mass/height2), and serum triglyceride levels. Log serum FGF21 levels revealed a modest but positive correlation with SMI (r = 0.30, p = 0.001) and independently predicted SMI after multiple adjustment (ß = 1.59, p = 0.027). During a median follow-up period of 66 months, all-cause mortality and cardiovascular death rates did not differ significantly between the high- and low-FGF21 groups. We also failed to demonstrate FGF21 as an independent predictor of all-cause mortality. CONCLUSION: Serum FGF21 levels exhibited a positive association with skeletal muscle mass but were not predictive of mortality in patients undergoing chronic HD.