Hyponatremia at the Emergency Department: a case-control study

Area of Science:

• Emergency Medicine
• Clinical Chemistry
• Internal Medicine

Background:

• Hyponatremia (HNA) is a frequent electrolyte imbalance linked to increased patient morbidity and mortality.
• Understanding the incidence and prognostic implications of HNA in the Emergency Department (ED) is crucial for patient outcomes.

Purpose of the Study:

• To determine the incidence of hyponatremia (HNA) in patients presenting to the Emergency Department (ED).
• To evaluate the prognostic value of HNA regarding patient outcomes, including hospital admission, complications, and mortality.

Main Methods:

• A retrospective observational case-control study was conducted over 10 months in an ED.
• Hyponatremic patients (Na<130 mmol/L) were matched 1:1 with normonatremic controls (Na 135-145 mmol/L) based on age, gender, and admission month.

Main Results:

• Hyponatremia (HNA) was identified in 2.4% of patients undergoing blood analysis.
• HNA patients exhibited higher rates of pre-existing asthma/COPD, solid tumors, diuretic use, and vomiting.
• HNA was associated with increased hospital/ICU admission, a higher incidence of complications (digestive, septic, respiratory, renal, cardiovascular), and a greater mortality rate (10% vs. 3%).

Conclusions:

• Hyponatremia (HNA) affects 2.4% of ED patients and is independently associated with the presence of solid tumors.
• HNA is an independent predictor of hospital death, underscoring its role as a significant prognostic marker.