[Serum sodium concentration profile for cirrhotic patients and its effect on the prognostic value of the MELD score]

To analyze the characteristics of serum sodium in decompensated cirrhosis and evaluate the prognostic ability of the model for end-stage liver disease (MELD) in Na-containing models. Patients diagnosed with decompensated cirrhosis at our hospital were enrolled for study between June 2005 and October 2010. Patients were classified among three groups, according to serum sodium concentration: less than 125 mmol/L, 125 to 135 mmol/L, and more than 135 mmol/L. Mortality rates among the three groups were compared by Kaplan-Meier survival analysis. In addition, the different serum sodium concentrations were analyzed for correlations between Child-Pugh score and complication incidence rates of portal hypertension. The area under the receiver operating characteristic (ROC) curve (AUC) was used to compare the predictive abilities of MELD, MELD-Na, and the integrated (i) MELD scores for 3-month, 6-month and 1-year mortalities. A total of 467 patients were analyzed, and 50.54% had hyponatremia ( less than 135 mmol/L). Sodium concentration was correlated with mortality, and Kaplan-Meier survival analysis indicated that mortality was significantly higher in each subgroup with lower sodium concentration (all, P = 0.000). Likewise, sodium concentration decreased in conjunction with increased severity of decompensation, as classified by Child-Pugh scoring (sodium: A more than B more than C; mortality: A less than B less than C). With the exception of digestive tract bleeding, complication incidence rates of hepatic encephalopathy, ascites, spontaneous bacterial peritonitis, and hepatorenal syndrome increased when sodium concentration decreased. For predicting 3-month mortality, the AUC scores of MELD were not significantly different from the MELD-Na and iMELD scores (P more than 0.05). For predicting 6-month and 1-year mortality, the AUC scores of MELD-Na and iMELD were significantly higher than those of MELD (P less than 0.05). Hyponatremia is correlated with mortality and complications in decompensated cirrhosis patients. Incorporation of Na into the MELD may enhance it's prognostic ability.