Factors associated with mortality in patients presenting to the emergency department with severe hypernatremia

Hypernatremia is a common electrolyte disorder associated with prolonged hospitalization and death. Severe hypernatremia is defined as a serum sodium (Na⁺) concentration >160 mmol/L. To the best of our knowledge, there is little information on patients with severe hypernatremia, Na⁺ >160 mmol/L. Therefore, in this study, we aimed to determine the frequency, demographic and clinical characteristics, comorbid conditions and treatment strategies in patients presenting to the emergency department with severe hypernatremia, and also to evaluate the effects of these factors on mortality. A retrospective chart review was performed on patients presenting to the emergency department between January 2011 and June 2014. Patients with Na⁺ >160 mmol/L were screened retrospectively via the hospital electronic information management system and patient medical record files. During the 3.5 years of screening, 256 patients (0.04 %) with Na⁺ >160 mmol/L presented to the emergency department. The mean age of the patients included in the study was 74.4 ± 15.2 years, mean Na⁺ level was 168.7 ± 7.4 mmol/L and, mean mortality was 49.5 % during the hospitalization. Multivariable Cox regression analysis showed that low systolic blood pressure, low pH, Na⁺ >166 mmol/L, increased plasma osmolarity, mean sodium reduction rate ≤−0.134 mmol/L/h, dehydration, and, pneumonia to be independently associated with mortality. This study describes the demographic and clinical characteristics of patients with Na⁺ >160 mmol/L in a large population along with comorbid conditions, incidence, treatment strategies and, its association with mortality.