Hyponatremia is associated with increased mortality and rehospitalization in patients hospitalized for heart failure.
Previous studies have demonstrated that hyponatremia is associated with worse in-hospital outcomes in patients with heart failure, but data is lacking on long-term adverse effects in these patients.
The authors of “Hyponatremia Is an Independent Predictor of Adverse Clinical Outcomes in Hospitalized Patients Due to Worsening Heart Failure,” published in the Journal of Cardiology, assessed the records of 1,659 patients in the Japanese Cardiac Registry of Heart Failure in Cardiology database to determine whether hyponatremia was associated with negative in-hospital as well as long-term outcomes.
Researchers looked at patient characteristics, clinical status on admission, and management during hospitalization according to serum sodium concentration on admission. One hundred seventy-six patients (10.6%) had serum sodium concentration <135mEq/mL on admission, whereas 1,483 (89.4%) had serum sodium concentration at admission of ≥135mEq/mL.
Nearly 60% of the cohort was male, and average age was 70.7 years. More than one-third (33.9%) of patients had ischemic heart failure, and mean left ventricular ejection fraction for the group was 42.4%.
After adjusting for covariates, the researchers reported that hyponatremia was independently associated with in-hospital death (OR 2.453, 95% CI 1.265-4.755, p=0.008). Hyponatremia was also significantly associated with adverse long-term outcomes including all-cause death (OR 1.952, 95% CI 1.433-2.657), cardiac death (OR 2.053, 95% CI 1.413-2.983), and rehospitalization due to worsening heart failure (OR 1.488, 95% CI 1.134-1.953).
Based on these results, the authors concluded that hyponatremia “was independently associated with not only in-hospital but also long-term adverse outcomes in patients hospitalized with worsening heart failure.”