New data question benefit of fluid restriction in chronic heart failure
Key takeaways:
- Fluid restriction has long been recommended for patients with HF.
- Restricted vs. liberal fluid restriction did not impact health status for patients with HF.
CHICAGO — A new study that looked at how liberal vs. restrictive fluid restriction impacts health status for patients with chronic heart failure found no added risks or benefits with either strategy, researchers reported.
Results of the FRESH-UP study were presented at the American College of Cardiology Scientific Session and simultaneously published in Nature Medicine.
“Fluid restriction in heart failure has been recommended to patients with heart failure for decades [based] on the intuitive assumption that patients should have a fluid restriction in order to prevent episodes of congestion. However ... although restricting fluid is a common recommendation for patients with heart failure, evidence in this area is of low quality,” Roland van Kimmenade, MD, cardiologist at Radboud University Medical Centre in Nijmegen, the Netherlands, said during a press conference.
Overall, 504 adults diagnosed with NYHA class II/III HF at least 6 months before enrollment were included in the FRESH-UP study. Participants were randomly assigned to fluid restriction of no more than 1,500 mL per day or liberal fluid intake with no restriction.
The primary outcome was health status at 3 months as assessed by Kansas City Cardiomyopathy Questionnaire overall summary score (KCCQ-OSS) adjusted for baseline values with analysis of covariance. The key secondary outcome was 3-month Thirst Distress Scale.
Baseline characteristics were similar between the two groups. Two-thirds were men, the mean age was 69 years and nearly all were white.
Most patients were taking renin-angiotensin-aldosterone system inhibitors, mineralocorticoid receptor antagonists and beta-blockers and approximately half were prescribed an angiotensin receptor-neprilysin inhibitor, SGLT2 inhibitor and/or loop diuretics. No paients had any change to their HF medical therapy within 14 days of enrollment.
During a 3-month period, the change in health status as assessed by KCCQ-OSS favored liberal fluid intake over restricted intake; however, the difference was not significant (adjusted mean difference, 2.17 points; 95% CI, –0.06 to 4.39; P = .06).
In subgroup analyses, the researchers found no significant differences between liberal or restricted fluid intake for the primary outcome, but the trend continued to favor liberal intake, according to van Kimmenade.
Patients with HF assigned to restricted fluid intake reported higher thirst distress compared with those assigned liberal intake (18.6 vs. 16.9; P = .001).
In addition, participants assigned to liberal fluid intake reported higher KCCQ clinical summary score (mean, 75.9 vs. 74.5; P = .032) and KCCQ total summary score (mean, 78.5 vs. 77.2; P = .02) compared with restricted fluid intake.
“The difference in KCCQ after adjustment for baseline scores after 3 months was 2.7 and in favor of liberal fluid uptake. However, the primary endpoint was not met,” van Kimmenade said during the press conference. “If we look at the Thirst Distress Scale, it was higher in the fluid restriction group; patients in the restriction group definitely suffered more from thirst. No differences were observed for safety events between the two groups. Therefore, the FRESH-UP study questions the benefit of fluid restriction in chronic heart failure patients.”
There were no significant differences for any other secondary outcome, including death, all-cause hospitalization, HF hospitalization and acute kidney injury, according to the results.
After the presentation, discussant Shelley A. Hall, MD, FACC, HF and transplant cardiologist and chief of transplant cardiology, mechanical circulatory support and advanced heart failure at Baylor Dallas, said, “For the old timers out there, it validates our eyebrow raise when they dropped the fluid restriction from 2 L to 1,500 mL. We can't manage volume in the hospital and yet we are trying to put stricter restrictions on patients. I was delighted to see the results of this trial. To say we were right: 2 L is absolutely fine.
“The other aspect is they were thirsty. When you're thirsty all the time, it's consuming. All you can think about is going and getting a drink. What I would take away from this trial is: Let's be a little kinder to our patients and ourselves; we probably don't have to be so harsh in pounding fluid restriction,” Hall said.
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I'm not sure this study closes the book on fluid restriction for chronic HF. It didn't quite meet statistical significance and it's a modest-sized study.
Directionally, it certainly supports the concept that liberal fluid intake is fine in HF, and certainly it looked like patients with the liberal fluid intakes, based on KCCQ scores, felt better after 3 months, whereas patients on fluid restriction did not, and felt thirsty.
The secondary endpoint was definitely a positive for liberal fluid intake in terms of the P value, and those assigned to fluid restriction definitely were thirsty without any benefit. That certainly supports the idea that liberal fluid intake is probably fine, and that we've harped on fluid restriction for all these years as part of the hallmark of care of patients with HF. That began in an era where we didn't have the four pillars of guideline-directed medical therapy. We've changed morbidity and mortality in that disease so much during the last 30-plus years. When I trained, perhaps fluid restriction had more of a benefit because we just weren't doing anything else for our patients. Now that we have the four classes of medications making a difference, we don't need to fluid restrict and we can have patients feel better by liberalizing their fluid intake.
You still have to wonder about patients with significant renal dysfunction. Patients in FRESH-UP had primarily normal renal function. The question in patients with more significant renal dysfunction is, are they going to get into trouble with liberal fluid intake? That remains an open question and might be a harder study to do.
University of Virginia Health
University of Virginia Health System Cardiovascular
Vice President, American College of Cardiology
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Van Kimmenade R, et al. Late-breaking clinical trials IV. Presented at: American College of Cardiology Scientific Session; March 29-31, 2025; Chicago (hybrid meeting).
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