Correcting serum sodium slowly was associated with longer length of stay and excess mortality.

Rapid overcorrection of hyponatremia has been associated with osmotic demyelination syndrome (ODS), but data also suggest that correcting sodium slowly might be associated with longer hospital length of stay and excess in-hospital mortality. To examine the relation between serum sodium correction rates and clinical outcomes, researchers performed a retrospective study of more than 3000 patients with severe hyponatremia (<120 mEq/L) who were admitted to two Massachusetts hospitals during a 25-year period.

The cohort was divided into three groups according to calculated correction rates: Slow (<6 mEq/L/24 hours), moderate (6 to 10 mEq/L/24 hours), and fast (>10 mEq/L/24 hours). About one third of the cohort fell into each group. The moderate-correction group was chosen as a reference, as that rate aligns with guideline recommendations.

In adjusted analyses, slow correction was associated with higher in-hospital mortality. Fast correction was associated with shorter hospital length of stay and lower mortality in a multivariable analysis, but with no difference in mortality in a propensity-weighted analysis. The overall incidence of ODS in the entire cohort was low (7 patients; 0.2%), and 5 of those cases occurred in patients with sodium correction rates of ≤8 mEq/L/24 hours.

Comment

The prevailing concern when treating patients with severe hyponatremiatraditionally has been to avoid rapid overcorrection of serum sodium levels. These data argue that repleting serum sodium too slowly might be the more important problem. ODS is an uncommon complication of correcting sodium levels and appears to occur because of patients’ clinical factors (e.g., alcohol-use disorder, other electrolyte derangements) rather than because of fast sodium correction.