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Abstract: FR-PO0573

Overcorrection of Hyponatremia Remains Associated with Decreased Mortality at One Year

Session Information

Category: Fluid, Electrolytes, and Acid-Base Disorders

  • 1102 Fluid, Electrolyte, and Acid-Base Disorders: Clinical

Authors

  • Mallory, Austin L., University of Iowa Hospitals and Clinics, Iowa City, Iowa, United States
  • Nizar, Jonathan, University of Iowa Hospitals and Clinics, Iowa City, Iowa, United States
  • Jalal, Diana I., Iowa City VA Medical Center, Iowa City, Iowa, United States
  • Griffin, Benjamin R., Iowa City VA Medical Center, Iowa City, Iowa, United States
Background

Correction of hyponatremia at a rate >8 mEq/L within 24 hours has recently been associated with improved in-hospital and 30-day mortality. However, known complications of hyponatremia overcorrection such as osmotic demyelination or increased frailty may not manifest early enough following overcorrection to be captured by these metrics. We hypothesized that the harms of overcorrection would become more apparent at 90-day and 1-year time points.

Methods

We included patients admitted to the University of Iowa Hospital from 2014-2023 with hyponatremia defined as an admission sodium level ≤130 mEq/L. Overcorrection was defined as an increase of >8 mEq/L within 24 hours of admission. The primary outcome was 1-year mortality, and secondary outcomes were in-hospital, 30-day, and 90-day mortality. We adjusted for confounding using 3 different methods: inverse probably of treatment weighting (IPTW), propensity-score matching, and forward stepwise multivariable regression. Covariates included age, sex, race, eight comorbidities including heart failure, liver disease, and malignancy, and seven laboratory values including admission sodium.

Results

There were 15,663 admissions with sodium levels ≤130 mEq/L, 6,086 with ≤125 mEq/L, and 1,795 with ≤120 mEq/L. Approximately 85% of admissions were from unique patients at each sodium level. Rates of overcorrection were 7.1%, 12.7%, and 22.2%, respectively. Mortality rates (Figure 1) were significantly lower in the Overcorrection group at all time-points, and in this group did not vary based on initial sodium. Using three statistical approaches, Overcorrection was independently associated with decreased mortality at all time-points including 1-year mortality (aOR 0.39, 95% CI 0.27-0.55 in IPTW analysis).

Conclusion

Using a variety of statistical techniques and sodium inclusion thresholds, overcorrection of hyponatremia within 24 hours of admission remained independently associated with decreased mortality extending to 1 year of follow-up.

Figure 1. Mortality percentage based on overcorrection status, initial sodium level, and time from hospital discharge.

Digital Object Identifier (DOI)