Ultrasound parameters of thigh soft tissues and their association with clinically significant fatigue and reduced muscle strength in patients with non-alcoholic fatty liver disease

Fatigue is a common systemic symptom of nonalcoholic fatty liver disease (NAFLD), negatively impacting quality of life and treatment adherence. Muscle dysfunction may contribute to its pathogenesis, but ultrasound characteristics of skeletal muscles in NAFLD have not been well studied. Objective: to assess the associations between ultrasound features of thigh soft tissues, muscle strength, and fatigue in NAFLD patients. Material and methods. This single-center study included 154 individuals with NAFLD (median age, 56 years; 59.1% women). All participants underwent ultrasound assessment of the quadriceps femoris, measurement of muscle strength using handgrip dynamometry and the five-times sit-to-stand test (5TSTS), and fatigue assessment with the Fatigue Assessment Scale (FAS). Clinically significant fatigue (CSF) was defined as FAS ≥22. Results. CSF was identified in 36.4% of participants and was associated with greater thigh subcutaneous fat thickness (ρ=0.202; p=0.003), lower relative handgrip strength (ρ=–0.187; p=0.032), longer 5TSTS duration (ρ=0.269; p=0.002), and smaller area and width of the rectus femoris (p<0.05 for all). In logistic regression, thigh subcutaneous fat thickness was the only independent predictor of CSF (p=0.009). The area under the ROC curve for subcutaneous fat thickness was 0.646 (p=0.008). Conclusion. Fatigue in NAFLD is linked to structural and functional muscle alterations. Thigh ultrasound may serve as a non-invasive method for detecting muscle dysfunction and stratifying CSF risk in clinical and research settings.