Sarcopenia in nonalcoholic fatty liver disease: new challenges for clinical practice

Introduction: Sarcopenia is increasingly recognized in patients with nonalcoholic liver disease (NAFLD). Initially recognized as a consequence of advanced liver disease, there is now emerging evidence that sarcopenia may be a novel risk factor for the development of NAFLD, with a role in fibrosis and disease progression.Areas covered: This review examines the epidemiology, pathogenesis, and complex interplay between NAFLD and sarcopenia. Furthermore, the authors discuss the challenges with diagnosis of sarcopenia in the clinic and the evidence-based management of sarcopenia in patients with NAFLD. A MEDLINE and PubMed search was undertaken using the terms; 'sarcopenia,' 'frailty,' 'muscle,' 'obesity,' 'non-alcoholic fatty liver disease,' 'non-alcoholic steatohepatitis', and 'cirrhosis' up to 31 September 2019.Expert opinion: Sarcopenia may be masked by the co-existence of morbid obesity, which is most notable in patients with NAFLD. Sarcopenia is a key indicator of adverse outcomes in patients with cirrhosis, such as hepatic decompensation, poor quality of life and premature mortality. Patients with NAFLD and advanced fibrosis/cirrhosis should undergo anthropometric measures (handgrip strength), dry body mass index, and measures of physical frailty (including muscle function, not just mass) to enable targeted early interventions of nutrition (low fat, 1.5 g/kg/day protein intake, 2-3 hourly food intake) and exercise (combined resistance and aerobic).