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).

CONCLUSION

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.