The impact of serum sodium concentration on mortality after liver transplantation: A cohort Multicenter study

Modification of the current allocation system for donor livers in the United States to incorporate recipient serum sodium concentration ([Na]) has recently been proposed. However, the impact of this parameter on posttransplantation mortality has not been previously examined in a large risk-adjusted analysis. We assessed the effect of recipient [Na] on the survival of all adults with chronic liver disease who received a first single organ liver transplant in the UK and Ireland during the period March 1, 1994 to March 31, 2005 (n = 5,152) at 3 years, during the first 90 days, and beyond the first 90 days, adjusting for a wide range of recipient, donor, and graft characteristics. Compared to those with normal [Na] (135-145 meq/L; n = 3,066), severely hyponatremic recipients ([Na] <130 meq/L, n = 541), had a higher risk-adjusted mortality at 3 years (hazard ratio [HR] 1.28; 95% confidence interval [Cl], 1.04-1.59; P < 0.02). The excess mortality was, however, confined to the first 90 days (HR 1.55; 95% Cl, 1.18-2.04; P < 0.002) with no significant difference thereafter. This was also true for hypernatremic recipients ([Na] >145 meq/L, n = 81), who had an even greater risk-adjusted mortality compared to normonatremic recipients (overall: HR 1.85; 95% Cl, 1.25-2.73; P < 0.002;<= 90 days: HR 2.29; 95% Cl, 1.42-3.70; P < 0.001; >90 days: HR 1.12; 95% Cl, 0.55-2.29; P = 0.8), whereas mildly hyponatremic recipients ([Na] 130-134 meq/L, n = 1,127) had similar risk-adjusted mortality to those with normal [Na] at the same time points. In conclusion, recipient [Na] is an independent predictor of death following liver transplantation. Attempts to correct the [Na] toward the normal reference range are an important aspect of pretransplantation management.