Role of Nutrition and Muscle in Cirrhosis

Most widely recognized complications in cirrhotic patients include ascites, hepatic encephalopathy, variceal bleeding, kidney dysfunction, and hepatocellular carcinoma; however, malnutrition and muscle wasting (sarcopenia) constitute common complications which negatively impact survival, quality of life, and response to stressors, such as infection and surgery in patients with cirrhosis. Despite the important role that malnutrition and sarcopenia play in the prognosis of patients with cirrhosis, they are frequently overlooked, in part because nutritional assessment can be a difficult task in patients with cirrhosis due to fluid retention and/or overweight. Moreover, patients with cirrhosis may develop simultaneous loss of skeletal muscle and gain of adipose tissue, culminating in the condition of "sarcopenic obesity." In addition, muscle depletion is characterized by both a reduction in muscle size and increased proportion of intermuscular and intramuscular fat-denominated "myosteatosis." Sarcopenia in cirrhotic patients has been associated with increased mortality, sepsis complications, hyperammonemia, overt hepatic encephalopathy, and increased length of stay after liver transplantation. Muscularity assessment with cross-sectional imaging studies has become an attractive index of nutritional status evaluation in cirrhosis, as sarcopenia reflects a chronic detriment in general physical condition, rather than acute severity of the liver disease. In this review, we discuss the current diagnostic methods to evaluate malnutrition and muscle abnormalities in cirrhosis and also analyze the current knowledge regarding incidence and clinical impact of malnutrition and muscle abnormalities in cirrhosis and their impact after liver transplantation. We also discuss existing and potential novel therapeutic strategies for malnutrition in cirrhosis, emphasizing the recognition of sarcopenia in cirrhosis in an effort to improve survival and reduce morbidity related to cirrhosis. Finally, we analyze new studies including sarcopenia with the MELD score that seems to allow better prediction of mortality among cirrhotic patients waiting for liver transplantation.