Abstract 16232: Prognostic Significance of Hyponatremia among Ambulatory Heart Failure Patients with Preserved Ejection Fraction
Background: Hyponatremia is an established predictor of adverse outcomes in patients with heart failure (HF) and reduced ejection fraction (HFrEF). However, the prevalence and prognostic significance of hyponatremia among ambulatory patients of HF with preserved ejection fraction (HFpEF) is unknown.
Methods: In a national ambulatory cohort of Veterans with HFpEF (ejection fraction >=50%), we examined the association of hyponatremia with all-cause mortality.
Results: Among 2,843 patients with HFpEF, hyponatremia (serum sodium < 136 mEq/L) was present in 376 (13.2%) patients and hypernatremia (sodium levels > 145 mEq/L) in 52 (0.02%) patients. The demographic profile, co-morbidity burden and ACE inhibitor/beta blocker use was similar in patients with and without hyponatremia. However, hyponatremic patients had lower body mass index and hemoglobin levels (p<0.001) and higher serum BUN (p<0.001) compared with the rest of the patients. Over 2-year follow-up, 28.2% of hyponatremic patients died, compared with 18.5% non-hyponatremic patients (p<0.001). Based on Martingale residual plots, serum sodium had a linear association with all cause mortality. Time to event analysis demonstrated higher risk of death in hyponatremic patients (Figure; p <0.001). After adjustment for demographics, comorbidities and medications in a Cox proportional hazards model, hyponatremia was associated with increased all cause mortality [HR: 1.46, 95% CI: 1.17 - 1.81; p=0.001].
Conclusion: Hyponatremia is a strong independent predictor of mortality among ambulatory HFpEF patients. As in HFrEF, hyponatremia in HFpEF may represent neurohormonal activation, volume overload or excessive diuretic therapy and identifies a higher risk group.
- © 2012 by American Heart Association, Inc.