Risk Stratification for Sarcopenic Obesity in Nonalcoholic Fatty Liver Disease

Abstract

We read with great interest the study by Chun et al and would like to congratulate the authors on providing more evidence on the presence of sarcopenia in those with nonalcoholic fatty liver disease (NAFLD) and its association with adverse outcomes, including liver fibrosis, cardiovascular disease, and mortality.1Chun H.S. et al.Clin Gastroenterol Hepatol. 2022; (In press)Google Scholar Obesity and sarcopenia appear to be synergistic culprits with higher morbidity and mortality when present simultaneously than when present separately.2Emhmed Ali S. et al.Life (Basel). 2021; : 11PubMed Google Scholar In addition, our systematic review and meta-analysis of 22 studies involving over 6000 individuals with cirrhosis revealed a 2.6-fold (95% confidence interval [CI], 2.28–2.98) increased mortality risk in patients with sarcopenia.3Tantai X. et al.J Hepatol. 2022; 76: 588-599Abstract Full Text Full Text PDF PubMed Scopus (42) Google Scholar The authors developed and validated a model to identify those with NAFLD who would be considered to be high-risk patients with sarcopenic obesity (SO) (ie, patients who were at high risk for developing liver cirrhosis [Fibrosis-4 >3.25] or cardiovascular disease [CVD] [atherosclerotic CVD score >20]).1Chun H.S. et al.Clin Gastroenterol Hepatol. 2022; (In press)Google Scholar The factors most associated were being male, being older, having a low sarcopenic index, and having metabolic syndrome.1Chun H.S. et al.Clin Gastroenterol Hepatol. 2022; (In press)Google Scholar In their long-term analysis, the mortality rate in patients at high risk for SO were 10.57-fold (95% CI, 1.28–88.04) higher than in those at low risk for SO, concluding that primary prevention of CVD is highly beneficial for the high-risk population of patients with NAFLD and SO. The global prevalence of NAFLD is increasing, and NAFLD may soon become the leading cause of end-stage liver disease.4Le M.H. et al.Clin Gastroenterol Hepatol. 2022; 20: 2809-2817Abstract Full Text Full Text PDF PubMed Scopus (0) Google Scholar,5Le M.H. et al.Clin Mol Hepatol. 2022; 28: 841-850Crossref PubMed Scopus (3) Google Scholar It is thus important that studies similar to the authors’ continue, and that there is further study of the pathophysiologic interaction between NAFLD and sarcopenia. Our current understanding is that the primary characteristic of SO is a loss of skeletal muscle due to infiltration of fat into the muscle, and the loss of skeletal muscle mass and function is one of the generally accepted “multiple-hit” hypotheses regarding the mechanism of NAFLD, which may occur through the presence of insulin resistance, vitamin D deficiency, and chronic low-grade inflammatory response.6Kim J.A. et al.Hepatol Int. 2019; 13: 674-687Crossref PubMed Scopus (0) Google Scholar In conclusion, we thank the authors for their outstanding work, which provides crucial evidence for the utilization of detailed SO stratification analysis and modeling of high-risk predictive factors to assess the progression of NAFLD and/or occurrence of CVD. Future expansion of the sample cohort to include real-world patients from more diverse racial ethnic backgrounds and geographic regions would boost the validity of this conclusion. Without effective medications, this approach of high-risk stratification will assist in identifying patients with NAFLD who may be at greater risk for poor outcomes.