Elevated serum tyrosine concentration is associated with a poor prognosis among patients with liver cirrhosis

Abstract

AIM: Chronic liver insufficiency is often associated with changes in amino acid metabolism. We evaluated whether change in serum amino acid concentrations had prognostic value among patients with liver cirrhosis. METHODS: This retrospective study evaluated 158 patients who had been hospitalized with cirrhosis. Baseline serum concentrations of branched-chain amino acids (BCAAs) and tyrosine, as well as the BCAA-to-tyrosine ratio, were evaluated. Cox proportional hazards analysis was used to calculate the hazard ratios for factors that were associated with mortality or liver transplantation. RESULTS: Among the 158 patients, baseline measurements showed decreased serum BCAA concentrations for 59 patients (37.3%), elevated serum tyrosine concentrations for 80 patients (50.6%), and a decreased BCAA-to-tyrosine ratio for 114 patients (72.2%). During a median follow-up period of 3.0 years, death or liver transplantation occurred at a rate of 0.136 cases/1 person-year. Multivariable analysis showed that transplant-free survival was independently predicted by older age, male sex, comorbid hepatocellular carcinoma, Child-Turcotte-Pugh score, and serum tyrosine concentration. Receiver operating characteristic curve analysis showed that a serum tyrosine concentration of >110 µmol/L was the optimal cut-off value for predicting transplant-free survival (adjusted hazard ratio 1.89, 95% confidence interval 1.15-3.11, p = 0.012). Kaplan-Meier analysis showed a significant difference in the 5-year transplant-free survival probability between patients with high and low serum tyrosine concentrations (42.1% vs. 60.7%, p < 0.001). CONCLUSIONS: Elevated serum tyrosine concentration, but not changes in serum BCAA concentration or the BCAA-to-tyrosine ratio, may indicate a high risk of death or liver transplantation for patients with liver cirrhosis.

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