Figure 4.

Kaplan–Meier survival curve analysis in total study population (A) and in subjects with preserved ejection fraction (HFpEF; B) or reduced ejection fraction (HFrEF; C), stratified by on‐admission serum sodium level and change of serum sodium level during hospitalization. Group 1=normonatremia on admission without any drop of serum sodium level during hospitalization; group 2=normonatremia on admission with a drop of serum sodium level during hospitalization; group 3=hyponatremia on admission without any drop of serum sodium level during hospitalization; group 4=hyponatremia on admission with a drop of serum sodium level during hospitalization.