BACKGROUND & AIM Anthropometric data are associated with nonalcoholic fatty liver disease (NAFLD) development and progression. We investigated whether the quantity and quality of muscle and visceral fat assessed by computed tomography (CT) are associated with fibrosis severity in NAFLD.

METHODS In a prospective biopsy-confirmed NAFLD cohort of 521 patients, we measured skeletal muscle index (SMI), muscle attenuation (MA) and visceral adipose tissue index (VATI) via CT. Low skeletal muscle mass (LSMM) was defined using previously validated cut-offs. Myosteatosis and visceral adiposity were defined as the lowest and highest quartile, respectively. Significant fibrosis was defined as F2-F4 in liver histology.

RESULTS Patients with significant fibrosis had lower SMI and MA and higher VATI than those without. The significant fibrosis prevalence was significantly higher in subjects with LSMM (45.1% vs 30.8%, P = .005), myosteatosis (46.1% vs 29.7%, P = .001) and visceral adiposity (46.9% vs 29.9%, P = .001) than those without. The significant fibrosis risk increased with increasing numbers of body composition components (24.5%, 35.6%, 53.0% and 72.7% in patients with 0, 1, 2 and 3 components respectively). Multivariable analysis revealed that LSMM (OR, 1.72; 95% CI, 1.05-2.84), myosteatosis (OR, 1.65; 95% CI, 1.01-2.68) and visceral adiposity (OR, 1.75; 95% CI, 1.09-2.83) were independent predictors of significant fibrosis. Subjects with sarcopenia had a higher risk of significant fibrosis (OR, 2.17; 95% CI, 1.03-4.56).

CONCLUSION Muscle alterations and visceral adiposity assessed by CT are associated with significant fibrosis in NAFLD. LSMM and myosteatosis have additive values in prediction of significant fibrosis.