Sodium restriction may not impact morbidity, mortality in patients with heart failure
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Key takeaways:
- Sodium restriction does not appear to affect morbidity and mortality in patients with heart failure but does offer quality of life benefits.
- Moderate sodium intake may be best for this population.
A narrative review found no evidence that sodium restriction affects morbidity and mortality in patients with heart failure.
“Overall, there is no evidence that severe sodium restriction reduces the incidence of mortality and hospitalization in patients with heart failure,” Paolo Raggi, MD, PhD, professor of medicine at the University of Alberta and academic director of Mazankowski Alberta Heart Institute in Edmonton, Alberta, Canada, wrote in the European Journal of Clinical Investigation. “Quality of life and functional class may improve slightly with sodium restriction.”
Extended sodium restriction ‘not sustainable’
Raggi wrote that the American Heart Association’s recommendation of restricting sodium to less than 1.5 g per day and WHO’s recommendation of restricting it to less than 2 g per day are influenced by the results of the DASH-Sodium trial and some small observational studies. However, he wrote, although DASH-Sodium showed an improvement in BP and a reduction in CV events in participants who restricted their sodium intake, the trial phase of the study was only 30 days, and other studies have shown that severely reducing sodium intake in the long term is not sustainable in the general population. Of note, he wrote, the randomized TOHP-II trial failed to show that very low sodium intake lowered the primary endpoint of diastolic BP at 36 months.
Sodium restriction does lower BP, but “the effect wanes with time, likely due to the intervention of compensatory mechanisms and the inability to sustain a severe sodium restriction,” he wrote.
The Salt Substitute and Stroke Study (SaSS) of patients at elevated risk for new or recurrent stroke, in which participants using a potassium-based salt substitute had lower rates of stroke, CV events and death than those consuming sodium as usual, suggests that substitution may be a better method to preserve heart health than sodium restriction alone, Raggi wrote.
The largest randomized trial of sodium restriction in patients with HF, SODIUM-HF, was stopped early for futility, showing no difference vs. usual sodium consumption in the primary outcome of death, CV hospitalization or CV-related ED visits, though quality of life and NYHA class improved in the sodium-restriction group compared with the control group, he wrote, noting the results were consistent with those of observational studies and meta-analyses of sodium restriction in the HF population. In addition, he wrote, potassium-based salt substitutes may raise risk for hyperkalemia in patients with HF.
There is also no solid evidence that fluid restriction provides clinically meaningful benefits for patients with HF, he wrote.
‘A moderate sodium intake ... seems prudent’
“There is no proven clinical benefit to be derived from a strict sodium intake, with or without fluid intake restriction,” Raggi wrote. “A moderate sodium intake of 3 g to 4.5 g per day seems prudent to afford an overall better quality of life and functional status for patients with heart failure, with the understanding that this will not improve life expectancy and hospitalization rate. For patients with recurrent hospital admissions with fluid overload, an intake of 2 g to 3 g per day may be recommendable.”
He wrote that moderate sodium intake can be achieved by emphasizing consumption of fruits and vegetables and avoiding prepared meals that are typically high in sodium.
“Doctors often resist making changes to age-old tenets that have no true scientific basis; however, when new good evidence surfaces, we should make an effort to embrace it,” Raggi said in a press release.
Reference:
- Is it time to stop recommending strict salt restriction in people with heart failure? https://www.eurekalert.org/news-releases/1049098. Published June 26, 2024. Accessed June 26, 2024.
Perspective
Back to TopJennie Stanford, MD, FAAFP, DipABOM
It is important to distinguish between different types of HF, whether it is due to systolic or diastolic heart dysfunction, as they respond differently to varying treatments. In both cases, it can be a challenge to maintain good blood output from the heart and avoid excess fluid in parts of the body. However, patients with systolic HF (reduced ejection fraction) are more likely to have recurrent hospital admissions for decompensation and fluid overload. Sodium is important to our overall fluid balance because water likes to follow sodium. While the kidneys can regulate water and sodium excretion to some degree, the more sodium that is consumed, the more water the body retains. As a result, in HF, where maintaining optimal fluid balance is often difficult, excess sodium can be problematic.
However, sodium is necessary for many functions in the body, including muscle contraction, nerve function and metabolic processes. Studies have demonstrated that limiting sodium below the recommended intake in patients with HF may increase the risk for death.
While the American College of Cardiology often recommends a sodium intake of 2,300 mg per day in patients with HF, sodium recommendations should be individualized to each patient, based on a number of factors. Patients should speak with their doctor or health care professional about the best recommended sodium intake for their overall health.
Many approaches to sodium limitations have been suggested in patients with HF, as this paper outlines. While severe sodium limitations to < 1.5 g of sodium per day in patients with HF were widely recommended in the past, the evidence to support this is limited at best. Furthermore, this is hardly sustainable in the long term, even for the most careful of patients.
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