Muscle function is superior to muscle mass in predicting 90-day mortality in patients with acute-on-chronic liver failure: A prospective study

Low muscle mass has been found to be associated with adverse outcomes in patients with acute-on-chronic liver failure. However, data regarding the prognostic role of low muscle function are limited. Therefore, we aimed to investigate the predictive effect of low muscle function on 90-d mortality in patients with acute-on-chronic liver failure. This prospective study consecutively enrolled acute-on-chronic liver failure patients from March 2021 to October 2022. Muscle function was assessed using the liver frailty index, and the time-dependent receiver operating characteristic curve with the highest Youden index was used to determine the optimal cutoff values of liver frailty index for diagnosing low muscle function. The study included 126 acute-on-chronic liver failure patients. The median liver frailty index was 3.89 (0.83), with 51 (40.5) patients classified as having low muscle function. Multivariate Cox analysis identified low muscle function (hazard ratio = 4.309; 95% CI, 1.795-10.345; P = 0.001) and number of organ failures (hazard ratio = 4.202; 95% CI, 2.040-8.656; P < 0.001) as independent risk factors for 90-d mortality. However, the multivariate analysis did not retain the significant effect of low muscle mass. Furthermore, multivariable logistic analysis revealed that age (odds ratio = 1.042; 95% CI, 1.002-1.083; P = 0.038), organ failures (odds ratio = 2.572; 95% CI, 1.331-4.968; P = 0.005), and low muscle mass (odds ratio = 6.607; 95% CI, 2.579-16.927; P < 0.001) were independent risk factors for low muscle function. The prognostic value of low muscle function was found superior to that of low muscle mass in patients with acute-on-chronic liver failure. Therefore, it is important to assess the muscle function and develop potential targeted treatment strategies in this population.