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Limited evidence to support reduced salt intake for heart failure patients
Although restriction of salt intake is recommended in many cardiovascular guidelines, high-quality evidence is lacking to support or repudiate advice to reduce salt intake in patients with heart failure, according to research published in JAMA Internal Medicine.
“Recent estimates suggest that more than 26 million people worldwide have heart failure,” Kamal R. Mahtani, PhD, deputy director at the Centre for Evidence Based Medicine at the University of Oxford, England, and colleagues wrote. “The syndrome is associated with major symptoms, significantly increased mortality, and extensive use of health care. Evidence-based treatments influence all these outcomes in a proportion of patients with heart failure. Current management also often includes advice to reduce dietary salt intake, although the benefits are uncertain.”
Mahtani and colleagues systematically reviewed randomized clinical trials to investigate whether reduced dietary salt in adult inpatients or outpatients with heart failure (n = 479) is clinically supported and beneficial. The researchers identified 2,655 studies, but only nine were eligible for inclusion.
The studies included measured primary outcomes including cardiovascular-associated mortality, all-cause mortality and adverse events, such as stroke and myocardial infarction, as well as secondary outcomes including hospitalization, length of inpatient stay, change in New York Heart Association (NYHA) functional class, adherence to dietary low-salt intake and changes in BP. Risk for bias varied among the studies.
There was insufficient data to determine if reduced dietary salt intake was associated with the primary outcomes of interest. Regarding the secondary outcomes, restriction of salt intake demonstrated no improvement in NYHA functional class in two outpatient-based studies, but significantly improved NYHA functional class in two other studies.
“Despite broad advocacy, uncertainty remains about the robustness of advice to reduce salt intake in patients with heart failure. ... A paucity of robust high-quality evidence was available to support or refute current guidance. Well-designed, well-described, and adequately powered studies are needed to reduce uncertainty about the use of this intervention,” Mahtani and colleagues concluded.
In an accompanying editorial, Clyde W. Yancy, MD, MSc, chief of cardiology in the department of medicine at Northwestern University Feinberg School of Medicine, wrote that the findings by Mahtani and colleagues are “worth contemplating.”
Patients with heart failure may benefit more by shifting from sodium restriction to a DASH (Dietary Approaches to Stop Hypertension)-like diet, according to Yancy.
“A pivot is long overdue,” he wrote. “The SODIUM-HF (Study of Dietary Intervention Under 100 mmol in Heart Failure) is under way. This is a good step forward but not enough. Further trials studying the DASH diet and other candidate diets in heart failure should be performed. Before we persist with unyielding recommendations for aggressive sodium restriction at significant costs for uncertain benefits and unknown harm, do the trials.” – by Alaina Tedesco
Disclosures: Mahtani and colleagues report receiving funding from the National Health Service National Institute of Health Research School for Primary Care Research. Yancy reports no relevant financial disclosures.