Association of Early Nephrology Consultation with Mortality in Patients with Severe Hyponatremia

Background: Hyponatremia is the most common electrolyte disorder and is encountered by physicians across multiple specialties. Its management requires precise correction of the serum sodium level, which may benefit from the involvement of specialists, particularly nephrologists. This study aimed to evaluate the impact of nephrology consultation on mortality. Methods: This retrospective observational study included patients with severe hyponatremia (serum sodium level ≤120 mEq/L) at admission or during hospitalization between January 2014 and June 2024 in two tertiary care centers. Nephrology consultation was defined as any therapeutic involvement by nephrologists within 24 hours of the onset of severe hyponatremia. The association of nephrology consultation with in-hospital and 30-day mortality was assessed using inverse probability of treatment weighting based on propensity scores. Results: A total of 942 patients were included in the analysis, of whom 342 (36%) received nephrology consultation and 600 (64%) did not. The median (interquartile range) age was 73 (62–82) years, 430 (46%) patients were female, and serum sodium levels were 118 (116–119) mEq/L. In weighted logistic regression analyses, nephrology consultation was associated with lower in-hospital and 30-day mortality (odds ratio OR, 0.55; 95% confidence interval CI, 0.37–0.83 and OR, 0.62; 95% CI, 0.40–0.96, respectively). Osmotic demyelination syndrome occurred in three patients, with no significant difference in incidence between the two groups ( P = 0.27). Conclusions: Early nephrology consultation was associated with lower in-hospital and 30-day mortality in patients with severe hyponatremia, underscoring the importance of collaboration between nephrologists and other specialties in its management.