Association Between Rate of Hypernatremia Correction and Mortality: A Retrospective Cohort Study Across a Regional Health System.

Background: Rate of correction in severe hypernatremia remains controversial. Although data increasingly supports rapid correction, hypernatremia is still often treated similarly to hyponatremia with a maximum rate of correction of 8-12 mmol/L per day due to concerns of neurological complications. This retrospective cohort study investigated the association between the rate of correction in hypernatremia and mortality. A secondary objective was to evaluate whether any adverse neurological outcomes were attributable to rapid correction.

Methods: A retrospective cohort study of patients with severe hypernatremia (serum sodium ≥155 mmol/L) was conducted across a health system in the United States between January and December 2023. Rates of correction were calculated using the time between peak serum sodium values and first eunatremic (serum sodium ≤145 mmol/L) or last known values. Patients were categorized by their hypernatremia correction rates into slow (≤8 mmol/L/day) or rapid (>8 mmol/L/day) correction groups. Mortality was compared between the two groups using Fisher's exact test and survival analysis for 90-day and one-year intervals. Multivariate Cox regression analysis was performed to evaluate for association between the rate of correction and mortality.

Results: Among 150 included patients, 33 underwent rapid correction. The slow correction group had higher Charlson Comorbidity Indices compared to the rapid correction group. No significant differences in 90-day (43% vs 33%, p=0.42) and one-year mortality rates (63% vs 52%, p=0.23) were observed between the slow and rapid correction groups. Subsequent chart review revealed no documented adverse neurological outcomes attributable to rapid correction. Multivariate analysis did not identify a significant association between correction rate and mortality (hazard ratio 1.00, p=0.27).

Conclusions: These findings add to the growing evidence challenging traditional concerns about rapid correction of hypernatremia in adults, suggesting that rapid correction rates exceeding 8 mmol/L/day do not increase mortality or cause adverse neurological events. These results support reconsidering rigid correction limits and highlight the need for further research on individualized treatment strategies.