Dietary sodium restriction in heart failure (HF) is a traditional component of HF care, but the sparse data on its impact on outcomes are conflicting. Nevertheless, the concept has physiological face validity, and American College of Cardiology/American Heart Association guidelines support “some degree” of sodium restriction in patients with symptomatic HF, in a class IIa recommendation based on expert consensus. Now, investigators have analyzed observational data on sodium restriction from HART, an NIH-sponsored study.
The substudy cohort contained 130 patients with symptomatic HF and restricted sodium intake (mean, <2,500 mg/day) and 130 propensity-score–matched patients with unrestricted intake (mean age, 63.5; 56% men; 75% with reduced ejection fraction). A food-frequency questionnaire was used to assess sodium intake at baseline and annually for 3 years. Propensity-score matching accounted for differences in demographic and clinical characteristics.
Sodium restriction was associated with a higher risk than unrestricted intake for the combined primary endpoint, death or HF hospitalization (42.3% vs. 26.2%; hazard ratio, 1.85), due to a significantly higher hospitalization rate. In secondary analyses, the risk was significantly higher in patients not treated with angiotensin-converting enzyme inhibitors or angiotensin receptor blockers than among those receiving these medications.
Reaching conclusions from this study is difficult because sodium intake was based only upon patient report and, more important, because of the observational study design, which is inevitably prone to unmeasured confounding. However, the study highlights the lack of evidence for a routine practice in HF care. Perhaps, planned studies — including a large randomized trial examining clinical outcomes with a low-sodium diet (SODIUM-HF; NCT02012179; N=1000) and a much smaller study assessing the quality-of-life impact of the DASH diet (GOURMET-HF; NCT02148679; N=60) — will provide more robust evidence. Until then, the benefits of the knee-jerk impulse to recommend strict sodium restriction to patients with HF are simply unknown. Although the current guideline recommendation for more modest restriction (<3 g daily) for patients with symptomatic heart failure seems reasonable, it is admittedly not evidence-based.
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- Hummel SL and Konerman MC.Dietary sodium restriction in heart failure: A recommendation worth its salt? JACC Heart Fail ; :. (http://dx.doi.org/10.1016/j.jchf.2015.10.003)
- Yancy CW.The uncertainty of sodium restriction in heart failure: We can do better than this. JACC Heart Fail ;:.