Sarcopenia as a Risk Factor for Mortality in NAFLD: How Should We Diagnose It?

Objectives: Sarcopenia increases the risk of nonalcoholic steatohepatitis (NASH) and cirrhosis in patients with nonalcoholic fatty liver disease (NAFLD). Subsequently, poorly managed NAFLD can result in adverse health outcomes. Lifestyle interventions are effective for both NAFLD and sarcopenia; however, diagnosis of sarcopenia in this population is not well defined. This review aimed to examine current methods to diagnose sarcopenia in NAFLD patients.

Methods: MEDLINE, EMBASE, and CINAHL databases were searched for articles published until July 2023 using the terms "Non-alcoholic fatty liver disease," "NAFLD," "fatty liver," "sarcopenia," and "myoatrophy." Studies were excluded if they included pediatric populations, did not diagnose both sarcopenia and NAFLD, or included patients with alternate causes of liver disease.

Results: Twenty studies, predominantly from Asian countries (14 [70.0%]), involving 68 848 participants (45.5% females) were included. In 15 studies, most participants had a BMI > 25 kg/m². Heterogeneity in the tools used to diagnose NAFLD was identified, with abdominal ultrasound being the most commonly used. European, Asian, and Australasian Sarcopenia Working Groups had differing diagnostic definitions of sarcopenia. Of the three potential diagnostic elements of sarcopenia (muscle mass, strength, function), all studies measured muscle mass, commonly through bioelectrical impedance analysis (12 [60.0%]). Seven studies (35.0%) measured muscle strength, with the majority (n = 6) utilizing hand grip strength. Four (20.0%) measured muscle function, through gait speed or a timed up-and-go test.

Conclusions: The lack of standardization in sarcopenia diagnosis for NAFLD patients is concerning. A consistent definition is necessary to prevent this comorbidity from being overlooked, improve care, and outcomes.