Self-Reported Sodium Intake and Sodium Vulnerability in Heart Failure With Preserved Ejection Fraction

Objective: To determine the pathophysiologic and prognostic meaning of patient self-reported sodium intake in heart failure (HF) with preserved ejection fraction (HFpEF).

Methods: This cohort analysis used data from the Treatment of Preserved Cardiac Function Heart Failure With an Aldosterone Antagonist (TOPCAT) trial of patients enrolled in the Americas. Tertiles of baseline self-reported sodium intake were used to assess the relationship between self-reported sodium intake and clinical presentation/outcome and interactions with treatment effect of spironolactone.

Results: Self-reported sodium intake of 1748 patients with HFpEF included in TOPCAT were divided according to tertiles of sodium intake (47% low, 35% moderate, and 18% high sodium intake). After covariate adjustment, lower self-reported sodium intake was associated with higher risk of HF hospital admission (P=.009). Patients with lower sodium intake had higher E-wave velocity, left ventricular end diastolic volume, and estimated plasma volume (P<.001). Lower sodium intake was associated with a larger treatment effect of spironolactone on HF hospitalizations (hazard ratio, 0.69; 95% CI, 0.53 to 0.91) vs the highest tertile (hazard ratio, 1.37; 95% CI, 0.79 to 2.38; interaction P=.030). In addition, linear mixed models indicated larger reductions in blood pressure, dyspnea, and edema (all interaction P<.001) in patients with lower sodium intake receiving spironolactone.

Conclusion: Low self-reported sodium level in HFpEF is associated with higher risk of HF hospital admissions and may indicate a sodium-vulnerable state; patients should not be falsely reassured that they are in a lower risk category despite greater adherence to medical recommendations.