Hyponatremia Is Associated With Increased Mortality in Children on the Waiting List for Liver Transplantation

Background. Our aim was to determine whether hyponatremia is associated with waiting list or posttransplantation mortality in children having liver transplantation (LT). Methods. A retrospective analysis of the united network for organ sharing/organ procurement transplantation network database on pediatric LT performed between 1988 and 2016 was conducted. Hyponatremia was defined as a serum sodium of 130 mEq/L or below. Subjects were divided into 2 age groups: I (0-6 y old) and II (7-18 y old). Patient survival before and after LT, as well as graft survival, were compared in patients with and without hyponatremia. Multivariable Cox proportional hazards models were constructed for perioperative mortality. Results. Data from 6606 children were available for analysis of waiting list mortality, and 4478 for postoperative mortality. The prevalence of hyponatremia at the time of registration was 2.8% and 3.7% at the time of LT. Waiting list mortality in patients with hyponatremia was significantly higher in group I (P < 0.001) but not in group II (P = 0.09). In group I, the relative risk of mortality adjusted to pediatric end-stage liver disease score was significantly associated with hyponatremia (P < 0.001). A sodium level below 130 mEq/L (hazard ration [HR] = 1.7), younger age (group I) (HR = 2.01), and need for dialysis (HR = 2.3) were independent predictors for increased waiting list mortality. There was no difference in overall postoperative patient or graft survival related to hyponatremia. Conclusions. Hyponatremia is associated with increased waiting list mortality for pediatric LT candidates, particularly in younger children. Future studies examining incorporation of age-specific serum sodium levels into organ allocation policies in children seems warranted based on our findings.