Potential Confounders in Identification of Sarcopenia in Cirrhosis
Authors: Yildiray Topcu, Fatih Tufan, Mehmet Akif Karan
Journal: Clinical Gastroenterology and Hepatology (2016)

We read the article by Tandon et al1Tandon P. et al.Clin Gastroenterol and Hepatol. 2016; (Epub ahead of print)Google Scholar entitled, "A Model to Identify Sarcopenia in Patients With Cirrhosis," which provides a simple assessment tool for the presence of sarcopenic muscle mass. The findings of this study indicated that utilization of body mass index and thigh muscle thickness measured by ultrasound might enable accurate identification of sarcopenia. We would like to comment on this well-designed and performed study. There is growing interest in research about sarcopenia and its risk factors. Although several definitions have been proposed, the most widely accepted assessment consists of muscle mass, muscle strength, and muscle function evaluation.2Cruz-Jentoft A.J. et al.Age Ageing. 2010; 39: 412-423Google Scholar Thus, performance of all 3 of these assessments is recommended for the accurate identification of sarcopenia. In this study, muscle strength was assessed using a widely used method, handgrip strength measurement. However, measurement of usual gait speed is recommended as the first step in the screening of sarcopenia.2Cruz-Jentoft A.J. et al.Age Ageing. 2010; 39: 412-423Google Scholar Because usual gait speed is a measure of functionality, there is a trend toward considering it as the most important component of sarcopenia.3McLean R.R. et al.J Gerontol A Biol Sci Med Sci. 2014; 69: 576-583Google Scholar Second, a possible confounder regarding sarcopenia is the fat infiltration in the muscles.4Therkelsen K.E. et al.Age (Dordr). 2016; 38: 31Google Scholar Because muscle mass plus the fat content of the muscles is taken into account rather than lean muscle mass when ultrasound-guided measurement is performed, obesity may lead to underestimation of the rate of sarcopenia. The absence of a significant difference between the muscle strength of sarcopenic and nonsarcopenic women (Supplementary Table 4; 18.5 ± 6.6 vs 21.6 ± 6.8 in sarcopenic and nonsarcopenic women, respectively, P = .1)1Tandon P. et al.Clin Gastroenterol and Hepatol. 2016; (Epub ahead of print)Google Scholar and the absence of an association between muscle strength and sarcopenia in women, unlike it was seen in men, suggest that the rate of sarcopenic muscle mass might have been underestimated, especially in women in this study. Third, there is an important association between vitamin D and muscle functions. Patients with cirrhosis are at increased risk for vitamin D deficiency because they tend to have less sunlight exposure and activation of vitamin D may be impaired because of liver dysfunction. We suggest that measurement of 25-hydroxy-vitamin D and parathyroid hormone levels may provide information about an important confounder of sarcopenia. Finally, an accurate measurement of muscle strength requires cooperation of the subjects. Notably, hepatic encephalopathy, which was not mentioned as an exclusion criterion in this study, might have influenced accurate assessment of muscle strength. We suggest that consideration of these factors is important to identify sarcopenia more accurately in patients with cirrhosis in future observational and interventional studies. A Model to Identify Sarcopenia in Patients With CirrhosisClinical Gastroenterology and HepatologyVol. 14Issue 10PreviewThe severe depletion of muscle mass at the third lumbar vertebral level (sarcopenia) is a marker of malnutrition and is independently associated with mortality in patients with cirrhosis. Instead of monitoring sarcopenia by cross-sectional imaging, we investigated whether ultrasound-based measurements of peripheral muscle mass, measures of muscle function, along with nutritional factors, are associated with severe loss of muscle mass. Full-Text PDF ReplyClinical Gastroenterology and HepatologyVol. 14Issue 11PreviewWe thank Topcu et al for their interest in our research. Their letter outlines the potential challenges with diagnosing sarcopenia in cirrhosis. Full-Text PDF