Sodium Correction Rates and Associated Outcomes Among Patients With Severe Hyponatremia

BACKGROUND: Slow correction of severe hyponatremia is recommended to prevent osmotic demyelination syndrome but is associated with higher mortality. OBJECTIVE: To examine the association between sodium correction rates and death or delayed neurologic events. DESIGN: Retrospective cohort study. SETTING: Twenty-one community hospitals of an integrated health system in northern California. PATIENTS: Adults hospitalized with a serum sodium level of 120 mEq/L or lower between 2008 and 2023. INTERVENTION: Maximum 24-hour rate of serum sodium correction (slow [<8 mEq/L], medium [8 to 12 mEq/L], or fast [>12 mEq/L; reference]). MEASUREMENTS: The primary outcome was a composite of 90-day death or delayed neurologic events (new demyelination, paralysis, epilepsy, or altered consciousness between 3 and 90 days from admission). Standardized risk differences (RDs) were generated using targeted maximum likelihood estimation. Heterogeneity of effect was assessed across grades of predicted risk. RESULTS: 13 988 patients were hospitalized with severe hyponatremia during the study period (median age, 74 years; 63% female). Comorbidities included congestive heart failure (24%), liver disease (18%), alcohol dependence (14%), and metastatic cancer (10%). The primary outcome occurred in 3000 patients (21%); 90-day death occurred in 2554 (18%), and 90-day delayed neurologic events occurred in 587 (4%). Compared with slow 24-hour sodium correction, both medium (RD, -5.6 percentage points [95% CI, -7.1 to -4.0 percentage points]) and fast (RD, -9.0 percentage points [CI, -11.1 to -6.9 percentage points]) correction rates were associated with lower adjusted risk for the primary outcome. Risk differences increased with higher predicted risk, whereas risk ratios remained similar. LIMITATIONS: Residual confounding; outcome ascertainment using diagnostic codes. CONCLUSION: Faster sodium correction is associated with lower risk for 90-day death or delayed neurologic events. Treatment guidelines should be reexamined. PRIMARY FUNDING SOURCE: The Permanente Medical Group Rapid Analytics Unit Program.