We sought to examine body composition using bioimpedance analysis in patients with metabolic dysfunction-associated fatty liver disease (MAFLD, 2014 males and 949 females). Factors linked to the fat-free mass index (FF index) were examined using univariate and multivariate analysis. An FF index < 18 kg/m2 in males and an FF index < 15 kg/m2 in females were defined as having decreased skeletal muscle mass. The median age and body mass index (BMI) were 55 years and 25.4 kg/m2 in males, and 57 years and 25.4 kg/m2 in females, respectively. The FF index strongly correlated with muscle mass index both in males (r = 0.999) and females (r = 0.999). The prevalence of patients with an FF index < 18 kg/m2 in males and an FF index < 15 kg/m2 in females was well stratified according to age, BMI, severity of FL, and FIB4 index. In the males, in the multivariate analysis, BMI (p < 0.0001), fat mass index (p < 0.0001), and waist circumference (p = 0.0050) were found to be significant factors linked to FF index. In the females, in the multivariate analysis, BMI (p < 0.0001) and fat mass index (p < 0.0001) were found to be significant. In conclusion, fat accumulation as reflected by BMI, which is an easily available marker, could be a useful indicator for the skeletal muscle mass in MAFLD.
Keywords: BMI; MAFLD; fat-free mass; sarcopenia; skeletal muscle mass.