Skeletal muscle index and muscle attenuation with liver cirrhosis as survival prognosticators by sex

Background and Objectives: It has been proven that skeletal muscle index (SMI) and muscle attenuation (MA) are correlated with outcomes in liver cirrhosis. However, whether there are sex differences in these factors remains unknown. We aimed to analyze the predictive ability of SMI and MA for the prognosis of cirrhotic patients of different sexes and promote computed tomography (CT) use in body composition assessment. Methods and Study Design: CT images taken at the 3rd lumbar vertebra from 223 patients were quantified for body composition. A Cox regression model was used to assess associations between mortality and body composition. Timedependent receiver operating characteristic curves were calculated to evaluate the predictive ability of SMI and MA for the 1-, 3- and 5- year mortality of cirrhotic patients. Results: The majority of patients with liver cirrhosis were male (64.6%), and there was a weak linear correlation between SMI and MA in males (r=0.33, p<0.001). In the sex stratified multivariate Cox regression analysis, SMI in males (HR=0.95; 95% CI, 0.91-0.98; p=0.002) and MA in females (HR=0.91; 95% CI, 0.87-0.96; p<0.001) were independently associated with mortality. The areas under the curve (AUCs) of SMI (AUC=0.718) and MA (AUC=0.705) were similar in the 5-year mortality prediction of males, while in females, MA (AUC=0.797) had a stronger predictive ability than SMI (AUC=0.541). Conclusions: SMI in males and MA in females are independent prognostic factors for liver cirrhosis. For females, MA may be a more sensitive indicator of mortality prediction than SMI, while in males, they are equivalent.