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

Table 3 Methods and outcomes when measuring muscle function in the setting of cirrhosis and liver transplant

Study	Method	Outcomes	Notes/limitations
Andersen et al[37]	Isokinetic strength of flexion and extension of six joints	Upper and lower extremity strength was decreased in cirrhotics vs controls	Only included patients with alcohol related cirrhosis
		Lower extremity strength was associated with lean body mass and mid arm circumference, an effect independent of severity of liver disease, neuropathy, biochemical data and recent alcohol use	The majority of patients had Child-Pugh A or B classification Included 24 cirrhotics and 24 controls
Tarter et al[98]	Isokinetic strength measured by upper and lower extremity peak force, peak torque, total work and power	Most measures of strength were decreased in cirrhotic patients vs controls	Study included 49 with alcoholic cirrhosis, 42 with non-acoholic cirrhosis and 50 controls
		There was no difference in any measure between those with alcohol vs non-alcohol related cirrhosis	No patient had consumed alcohol in greater than one year prior to testing
Beyer et al[35]	Maximal oxygen uptake measured on a cycle ergometer SMWT Isokinetic knee flexion and extension	Maximal oxgen uptake, SMWT and isokinetic knee strength increased over the first six months after transplant compared to pretransplant values No changes were noted between six and 12 mo after transplant	Small study with only 17 patients having post transplant data and 13 patients completing both pretransplant and posttransplant assessment of maximal oxygen uptake Used a supervised exercise program after transplant
Epstein et al[38]	Symptom limited cardiopulmonary testing on a cycle ergometer	When examining patients that went on to transplant, a significantly higher proportion of patients that died within the first 100 post-operative days had a peak oxygen consumption < 60% predicted and had oxygen consumption at the anaerobic threshold < 50% predicted peak oxygen consumption	Median MELD at the time of exercise testing was low (7-12) The median time from exercise testing to transplant was long (471 ± 300 d)
Prentis et al[39]	Symptom or exertional limited cardiopulmonary testing on a cycle ergometer	Sixty tested patients went on to liver transplant with a 10% 90 d mortality	Mean MELD at transplant was low (< 20)
		Mean aerobic threshold was higher in survivors and was only variable in multivariate analysis that was associated with mortality	Compared to above study (Epstein 2004[38]), the authors did not make comparisons to population based reference values, but used ROC curve analysis to define thresholds associated with outcomes
		Optimal anaerobic threshold associated with survival was > 9 mL/min per kg
		Anaerboic threshold > 11 mL/min per kg was associated with shorter stay in critical care setting
Carey et al[34]	Six minute walk test	Candidates awaiting liver transplant had decreased SMWT distance (369 ± 122 m), significantly lower than reference values	Included patients too ill to walk, and designated zero m for this group
		When controlling for other factors including age and MELD, SMWT distance was significantly associated with wait list mortality (HR = 0.58, 95%CI: 0.37-0.93)
		ROC analysis found cut off value of 250 m having the highest sensitivity and specificity for mortality	Designated patients removed from the list as a waitlist death
Alameri et al[36]	Six minute walk test	Patients with cirrhosis had significantly diminished SMWT distance (306 ± 111 vs 421 ± 47 m, P < 0.0001)	Used Child-Pugh to assess severity of liver disease, no data on MELD
		SMWT was an independent predictor of survival and was inversely correlated with Child-Pugh classification
		The lowest quartile walked < 250 m

SMWT: Six minute walk test; MELD: Model for end stage liver disease.