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.