Sarcopenia and liver transplant: The relevance of too little muscle mass

Table 2 Measures, definitions and outcomes relating to sarcopenia in the setting of cirrhosis and liver transplant

Study	Method	Definitions used/proposed	Outcomes	Notes/Limitations
Selberg et al[96]	BIA, phase angle	> 5.4° normal 4.4°-5.4 borderline < 4.4° abnormal	Phase angle < 5.4° associated with significantly lower survival	Phase angle may remain normal in cases of severe tissue loss when proportional losses of extracellular mass and body cell mass may occur
Kaido et al[11]	BIA, multiphase device (InBody 720; BioSpace, Tokyo, Japan)	< 90% skeletal muscle mass compared to standard or body cell mass below 23.0 kg	Survival was significantly decreased in recipients with low skeletal muscle mass or low body cell mass	No data is provided on volume status, although Child-Pugh classification is given
	Percent skeletal muscle mass against a standard and calculated body cell mass			Nutritional supplementation with branched chain amino acids improved survival in those with low skeletal muscle mass
Englesbe et al[15]	CT, combined area of right and left psoas muscle area at the highest level of the 4th lumbar vertebra Control population was 248 trauma patients	Percentile cutoffs for total psoas area in transplant population 1910 mm2 50th percentile 1420 mm2 25th percentile 950 mm2 5th percentile	Decreased psoas muscle area associated with higher risk of mortality 25th percentile HR = 1.88 5th percentile HR = 3.46	Retrospective definitions of sarcopenia were not derived from the control trauma patients, but were based on percentiles from the transplant population Included CT scans either 90 d before or after transplant; majority of scans were after transplant
Tandon et al[12]	CT or MRI, cross sectional area of muscle at 3rd lumbar vertebra (psoas, paraspinals, transversus abdominis, rectus abdominis and internal and external obliques)	Total L3 skeletal muscle area ≤ 52.4 cm2/m2 in males ≤ 38.5 cm2/m2 in females	Sarcopenia present in 41% of wait listed candidates Higher wait-list mortality with sarcopenia (HR = 2.36, 95%CI: 1.23-4.53) Greatest effect was in those with low MELD score	Retrospective Only study to report use of both MRI and CT
Montano-Loza et al[18]	CT cross sectional area of muscle at 3rd lumbar vertebra (psoas, paraspinals, transversus abdominis, rectus abdominis and internal and external obliques) Muscle identified by Housfield unit between -29 and + 150	Total L3 skeletal muscle area ≤ 52.4 cm2/m2 in males ≤ 38.5 cm2/m2 in females	Sarcopenia present in 40% of cirrhotics Sarcopenia was independent risk factor for mortality (HR = 2.28, P = 0.008) One year survival for cirrhosis with sarcopenia was 53% compared to 83% in cirrhosis without sarcopenia	Prospective data
Hamaguchi et al[14]	CT, cross sectional psoas muscle area at level of umbilicus Intramuscular fat accumulation of multifidus muscle (multifidus muscle Housfield units/subcutaneous fat Housfield units)	ROC curves selected from study data for best accuracy in predicting death Intramuscular adipose tissue content -0.375 in males and -0.216 in females Psoas muscle mass normalized for height ≤ 6.868 cm2/m2 in males ≤ 4.117 cm2/m2 in females	Pretransplant increased intramuscular adipose tissue content (OR = 3.898, 95%CI: 2.025-7.757) and decreased psoas muscle mass (OR = 3.635, 95%CI: 1.896-7.174) were associated with mortality	Used umbilical level which can vary based on body habitus Constructed cutoffs based on diseased population Included intramuscular fat content as a measure of muscle quality
Tsien et al[13]	CT cross sectional at mid 4th vertebra level	Psoas muscle area normalized 5th percentile cutoffs ≤ 12.27 cm2/m2 in males less than 50 yr of age	Sarcopenia was seen in 62.3% prior to transplant and increased to 86.8% after transplant	Includes serial measures in the same patients
	Total cross sectional area of psoas, paraspinals and abdominal wall muscles (rectus abdominis, oblique and transversus abdominis) normalized to height	≤ 10.12 cm2/m2 in males more than 50 yr of age ≤ 10.47 cm2/m2 in females less than 50 yr of age ≤ 10.33 cm2/m2 in females more than 50 yr of age	Only 6.1% had reversal of sarcopenia after transplant and 75% without pretransplant sarcopenia developed it after transplant	Mean time from transplant to post-transplant CT was about one year (13.1 ± 8.0 mo)
	Reference ranges derived from 109 healthy control subjects undergoing CT for unspecified abdominal pain	Total abdominal muscle area normalized 5th percentile cutoffs ≤ 60.09 cm2/m2 in males less than 50 yr of age ≤ 48.97 cm2/m2 in males more than 50 yr of age ≤ 53.43 cm2/m2 in females less than 50 yr of age ≤ 41.28 cm2/m2 in females more than 50 yr of age	Reduction in muscle after transplant was associated with new onset diabetes mellitus	Since follow up scan was done for indications (ie HCC surveillance, infection, pain, increased aminotransferases) the potential for significant selection bias exists
Masuda et al[9]	Cross sectional CT of psoas muscle at L3 Calculated area by multiplying major and minor axis of psoas (a × b ×∏)	< 800 cm in men < 380 cm in women	3 and 5 yr survival with sarcopenia was 74.5% and 69.7% respectively, without sarcopenia was 88.9% and 85.4% respectively (P = 0.02)	Enteral nutrition given in immediate post operative period appeared to decrease risk of sepsis when sarcopenia was present
	Compared to a reference group of healthy donors		Sepsis was seen in 17.7% with sarcopena, 7.4% without sarcopenia (P = 0.03)

MELD: Model for end stage liver disease; CT: Computed tomography.