The principal investigator notes that some patients have seen benefits, including improvements in quality of life and less progression of heart failure over time.
WASHINGTON, DC – Eating less dietary sodium does not reduce mortality or hospital trips in heart failure (HF) patients with reduced or preserved ejection fraction, according to the SODIUM-HF trial.
Despite the lack of impact on clinical parameters, patients assigned to sodium restriction saw greater improvements at 6 months and 1 year in the global score and physical limitations on the Kansas City Cardiomyopathy Questionnaire (KCCQ) , and they had modest gains in NYHA functional class at 6 months and 1 year compared to a usual care group.
“The main takeaway from the overall trial is that although the primary endpoint of reduction in all-cause death, cardiovascular hospitalizations or emergency room visits was statistically neutral, there were a numerically lower number event rates in patients on a low-sodium diet or consuming less dietary sodium,” said Justin A. Ezekowitz, SODIUM-HF Principal Investigator, MBBCh (University of Alberta, Canada ), at the TCTMD.
In the multicenter study, patients randomized to a low-sodium diet limited their intake to less than 1,500 mg per day for one year. The study, which was presented here in a late-breaking trial session at the American College of Cardiology (ACC) 2022 Scientific Session and simultaneously published in the Lancetwas stopped early after enrolling only about half of the intended patient population.
Ezekowitz said the study was given a low number of event rates to detect a statistically significant difference, the gains in quality of life merit further investigation.
The trial recruited 806 patients from 26 medical centers in Canada, Australia, New Zealand, Mexico, Colombia and Chile. About one-third were hospitalized for HF in the past 12 months, and the median ejection fraction was 36%. Those assigned to a low-sodium diet (n=397) received nutritional and behavioral counseling as well as specialized menus to help them choose low-sodium foods, while those assigned to usual care (n=409) received general tips for limiting sodium.
The median daily sodium intake at baseline for the intervention group was 2286 mg, which declined to a median of 1658 mg at 1 year. The usual care group had a baseline median daily intake of 2119 mg, which fell slightly to a median of 2073 mg.
The primary composite outcome of CV hospitalization, emergency department visit, or all-cause mortality occurred in 15% of the low sodium diet group (60 events) and 17% of the usual care group at 1 year (70 events; P = 0.53), which remained constant across a variety of subgroups. Additionally, there were no significant differences between the groups in the individual components of the primary endpoint.
For the global KCCQ summary score, there was a mean difference between the groups of 3.38 points in the change from baseline to 12 months, 3.29 points in the clinical summary score and 3.77 points in the physical limitations. In an analysis stratified by gender, there was no treatment-gender interaction on quality of life. Additional analysis found no interactions between the primary outcome and baseline dietary sodium, baseline renin-angiotensin system inhibitor use, or geographic region.
With respect to NYHA functional class, patients on the low-sodium diet were more likely than those in the usual care group to show one class improvement at 12 months (P = 0.0061).
Thresholds and Future Considerations
The recommended amount of dietary sodium for patients with HF varies by guideline, with the Heart Failure Society of America recommending no more than 2,000 to 3,000 mg per day depending on symptoms and the American Heart Association advocating no more. of 1500 mg per day but recognizing that there is insufficient data to support a specific level of sodium intake for patients with symptomatic or advanced heart failure.
“I don’t think we know what the best threshold is,” Ezekowitz warned, noting that the guidelines for dietary sodium goals are based on epidemiological data. Although it can be daunting to ask patients to reduce their daily intake, he said SODIUM-HF shows that patients with HF can reduce their sodium intake without feeling coerced or limited in their choices.
“We’ve tried to carefully balance the diets, so we’re only changing dietary sodium rather than other factors, such as the amount of calories, protein, or potassium,” he said. “Unlike other diets, such as the DASH diet, which tests for lower sodium with higher potassium in the diets of people with hypertension, our goal was simply to test for a single component drop, and I think we’ve achieved that.”
Ezekowitz and colleagues state that it is possible that longer follow-up and/or a lower daily sodium threshold may lead to differences in mortality and hospitalization.