Objectives: To assess the epidemiology of nonoptimal hyponatremia correction and to identify associated morbidity and in-hospital mortality.
Patients and methods: An electronic medical record search identified all patients admitted with profound hyponatremia (sodium <120 mmol/L) from January 1, 2008, through December 31, 2012. Patients were classified as having optimally or nonoptimally corrected hyponatremia at 24 hours after admission. Optimal correction was defined as sodium correction in 24 hours of 6 through 10 mmol/L. We investigated the association between sodium correction and demographic and outcome variables, including occurrence of osmotic demyelination syndrome (ODS). Baseline characteristics by correction outcome categories were compared using the Kruskal-Wallis test for continuous variables and the χ(2) test for categorical variables. Odds ratios for in-hospital mortality between groups were assessed using logistic regression. Adjusted differences in hospital length of stay (LOS) and intensive care unit (ICU) LOS were assessed using the Dunnett 2-tailed t test.
Results: A total of 412 patients satisfied inclusion criteria of whom 174 (42.2%) were admitted to the ICU. A total of 211 (51.2%) had optimal correction of their hyponatremia at 24 hours, 87 (21.1%) had undercorrected hyponatremia, and 114 (27.9%) had overcorrected hyponatremia. Both patient factors and treatment factors were associated with nonoptimal correction. There was a single case of ODS. Overcorrection was not associated with in-hospital mortality or ICU LOS. When adjusted for patient factors, undercorrection of profound hyponatremia was associated with an increase in hospital LOS (9.3 days; 95% CI, 1.9-16.7 days).
Conclusion: Nonoptimal correction of profound hyponatremia is common. Fortunately, nonoptimal correction is associated with serious morbidity only infrequently.
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