Prevalence of and Impact on the Outcome of Myosteatosis in Patients with Hepatocellular Carcinoma: A Systematic Review and Meta-Analysis

Simple Summary: Hepatocellular carcinoma (HCC) is recognized as one of the most prevalent malignancies worldwide, presenting a substantial healthcare challenge. Myosteatosis, known as the accumulation of fat in the muscles, has raised an escalating interest among patients with several malignancies. The aim of our systematic review/meta-analysis was to assess the prevalence of myosteatosis in individuals diagnosed with HCC. Our study revealed that myosteatosis is highly prevalent in HCC patients and is associated with more severe underlying liver disease and higher mortality rates. Our findings also suggest that the prevalence of myosteatosis in HCC patients varies depending on the etiology of the liver disease, while variations in myosteatosis prevalence were observed regardless of whether body mass index-based or gender-based criteria were used. Background: Limited data exist on the prevalence of myosteatosis (i.e., excess accumulation of fat in skeletal muscles) in hepatocellular carcinoma (HCC) patients, and no systematic review or meta-analysis has been conducted in this context. Methods: We searched for articles published from inception until November 2023 to assess the prevalence of myosteatosis in patients with HCC. Results: Ten studies with 3316 patients focusing on myosteatosis and HCC were included. The overall prevalence of myosteatosis in HCC patients was 50% [95% Confidence Interval (CI): 35-65%]. Using the body mass index-based criteria (two studies), the prevalence was 34%, while gender-based criteria (eight studies) yielded 54% (p = 0.31). In Asian studies (n = 8), the prevalence was 45%, compared to 69% in non-Asian countries (two studies) (p = 0.02). For viral-associated HCC (eight studies), the prevalence was 49%, rising to 65% in non-alcoholic fatty liver disease-associated cases (three studies) and 86% in alcoholic liver disease-associated cases (three studies) (p < 0.01). The prevalence of myosteatosis was higher in Child-Pugh class C (3 studies, 91%) than in A (7 studies, 73%) or B (6 studies, 50%) (p = 0.02), but with no difference between Barcelona Clinic Liver Cancer stage A (3 studies, 66%), B (4 studies, 44%) and C (3 studies, 62%) (p = 0.80). Patients with myosteatosis had a significantly higher mortality (six studies) (Relative Risk: 1.35 (95%CI: 1.13-1.62, p < 0.01). Conclusion: The prevalence of myosteatosis is high in HCC patients and is associated with more severe liver disease and higher mortality rates.