Hyponatremia is associated with an increased risk of mortality on the liver transplantation (LT) waiting list. Although the incorporation of the serum sodium (Na) level into the Model for End-Stage Liver Disease score may reduce wait-list mortality, concerns remain about a potential association between pre-LT hyponatremia and decreased post-LT survival. Furthermore, the relationship between pre-LT hypernatremia and post-LT survival remains unexplored. The purpose of this study was to investigate the impact of the entire spectrum of pre-LT serum Na levels on post-LT outcomes. We identified 19,537 patients from 2003 to 2010 for whom serum Na levels immediately before LT were available. The patients were divided into 3 groups [hyponatremic (Na ≤ 130 mEq/L), normonatremic (Na = 131-145 mEq/L), and hypernatremic (Na > 145 mEq/L)], and their post-LT outcomes were compared. There was no difference in in-hospital mortality or 90-day survival between patients with hyponatremia and patients with normonatremia. A fraction of the patients (2.4%) had hypernatremia, which was associated with increased in-hospital mortality (11.2% versus 4.2%, P < 0.001) and diminished 90-day survival (86.4% versus 94.0.%, P < 0.001). After adjustments for important clinical variables, the association of pre-LT hypernatremia with posttransplant mortality remained significant with a hazard ratio of 1.13 for each unit increase in the Na level > 145 mEq/L (P < 0.001). The duration of the hospitalization after LT was significantly longer for hypernatremic patients (P < 0.001). In conclusion, hyponatremia per se does not affect post-LT survival. Pre-LT hypernatremia is a highly significant risk factor for post-LT mortality.
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