FIGURE 2.

The association of serum sodium at hospital presentation and mortality demonstrated a U-shaped pattern. Both hyponatremia and hypernatremia were significantly associated with mortality, which was more pronounced at the extremes of serum sodium, even after adjustment for demographic, comorbid conditions and illness severity (A). Following correction of serum sodium for serum glucose using the Katz (B) and Hillier (C) formulas, serum sodium levels in the hypernatremic range remained significantly associated with in-hospital death, but levels in the hyponatremic range were no longer associated with mortality. A serum sodium value of 140 mEq/L was used as the reference value.