Prevalence of Hypernatremia Among Medically Hospitalized Patients and the Related Clinical Outcomes

Hypernatremia is frequently observed, with prevalence varying widely depending on hospital clinical settings. It has been identified as an indicator of mortality and morbidity in critically ill patients. This study aimed to examine the prevalence, health implications, and predictors of hypernatremia among hospitalized patients with medical illnesses.

This retrospective study included adult patients (≥ 18 years) admitted to a tertiary care hospital. Serum sodium levels were documented upon admission and at the time of discharge. Hypernatremia was defined as a sodium concentration > 145 mmol/L.

A total of 424 patients met the inclusion criteria, of whom 34 (8.02%, 95% Cl: 5.78-11.02%) had hypernatremia on admission. There were 189 (44.6%) female patients, and the median age was 59.0 (IQR = 40.5-73.0) years. Aging was associated with severe hypernatremia (p< 0.010), and patients with severe hypernatremia had lower concentrations of potassium and albumin (p< 0.010). Patients who received normal saline (0.9%) during hospitalization showed a significant improvement in sodium concentration at discharge compared to the concentrations upon admission (141.0 vs. 149.5 mmol/L; p< 0.01). Patients with hypernatremia experience a considerably higher risk of inpatient mortality (p =0.024). Serum albumin concentration had negative associations with the likelihood of hypernatremia (adjusted odds ratio (aOR) = 0.92, 95% CI: 0.88-0.96; p< 0.010) and inpatient mortality (aOR = 0.82, 95% CI: 0.79-0.87; p< 0.001).

Hypernatremia is prevalent among older adults and patients with hypovolemia. It is often associated with hypokalemia and hypoalbuminemia and may potentially lead to adverse health outcomes, including increased inpatient mortality.