Impact of organ dysfunction on outcomes in pediatric hypernatremia: a retrospective observational study.

Background: Hypernatremia is associated with increased mortality risk in pediatric patients. However, its impact on outcomes remains unclear. This study aimed to clarify the clinical backgrounds of contemporary children with hypernatremia and identify prognostic factors, including the impact of organ dysfunction on mortality.

Methods: We conducted a retrospective observational study of children under 18 years of age with hypernatremia (serum sodium ≥ 150 mmol/L) at a tertiary pediatric hospital in Japan between December 2021 and May 2023. Patient characteristics, clinical course, mortality rate, and occurrence of intracranial hemorrhage were analyzed. Kaplan-Meier and multivariable Cox proportional hazard analyses assessed 180-day survival and mortality risk factors.

Results: Out of 9,208 children admitted, 116 (1.2%) with hypernatremia were finally analyzed; 91% had underlying chronic diseases and 91% had hospital-acquired hypernatremia. Before onset, 85% had medication related to hypernatremia, 80% received intravenous fluids, and 63% were managed with nil per os. Survival rates were 87.9%, 83.6%, and 81.9% at 30, 90, and 180 days from the onset of hypernatremia, respectively. Cox proportional hazard analysis reveal that four or more organ dysfunctions (odds ratio 5.83, 95%CI 1.92-17.7, P = 0.002) significantly correlated with death, after adjusting for intravenous fluids and peak sodium level. Two patients (2%) developed new subdural hematomas after the onset of hypernatremia.

Conclusions: Pediatric hypernatremia predominantly occurs in medically complex children and is mostly hospital-acquired. The number of organ dysfunctions is a strong predictor of mortality in children with hypernatremia.