Fluid restriction good for chronic HF: Aye or nay?

Allowing patients with chronic heart failure (HF) to drink as much fluid as they need appears to present no additional risks, including for hospitalization and death, as shown in the FRESH-UP study presented at ACC.25. This finding challenges the current US and EU recommendations to limit daily fluid intake to 1.5 L for this population.

Three months into the trial, patients experienced similar changes in Kansas City Cardiomyopathy Questionnaire Overall Summary Scores (KCCQ-OSS) — a measure of symptoms and physical limitations associated with living with HF — regardless of whether they were allowed liberal fluid intake or had fluid restricted to under 1.5 L daily (74 vs 72 points).

The adjusted between-group difference in improvement was 2.17 points favouring liberal fluid intake (95 percent confidence interval [CI] -0.06 to 4.39; p=0.060). However, it did not meet expectations for a statistically significant finding. [Nat Med 2025; doi:10.1038/s41591-025-03628-4]

“This suggests that we have no reason to believe that fluid restriction would be better for stable HF,” said senior investigator Dr Roland van Kimmenade, a cardiologist at Radboud University Medical Centre in Nijmegen, Netherlands, during a press conference at ACC.25.

A contentious issue

Fluid restriction is commonly recommended for HF patients. It has long been considered beneficial because it counteracts the activated renin–angiotensin–aldosterone system and sympathetic nervous activity. This is based on the idea that limiting fluid intake would help prevent congestion episodes. However, little evidence supports this approach, and it remains a topic of ongoing debate among experts.

Cutting back on fluids also bothers patients, according to van Kimmenade. “Our study questions the benefit of fluid restriction in patients with chronic HF.”

The multicentre, open-label trial included 504 adult patients with chronic HF and New York Heart Association classes II and III symptoms. From 2021 to 2024, the patients were randomly assigned to fluid restriction (<1.5 L intake/day) or liberal fluid intake. Those with hyponatraemia and severe kidney failure were excluded from the study. Patients who had recent changes in HF therapy, had recent HF hospitalization or revascularization, or who underwent cardiac device implantation within 3 months before randomization were also excluded.

The mean age of the patients was 69 years. Approximately 67 percent were male, and almost 98 percent were White. The mean left ventricular ejection fraction (LVEF) was 40 percent, and about half of the cohort had reduced EF. Twenty-two percent had diabetes; mean estimated glomerular filtration rate (eGFR) was 62 mL/min/1.73 m². The majority were taking renin-angiotensin-aldosterone system inhibitors and beta-blockers. Sixty percent were on SGLT2 inhibitors.

Researchers had hoped that FRESH-UP would improve the quality of life (QoL) of the patients assigned to liberal fluid intake. However, after 3 months of follow-up, patients who consumed as much fluid as they wanted experienced only a slight increase in their QoL. Conversely, those on restricted fluid intake showed only a slight decrease. Even the differences in KCCQ scores were negligible.

The liberal-fluid recommendation was not linked with any adverse outcomes, including no differences in mortality, hospitalizations, use of intravenous loop diuretics, acute kidney injury, or changes in loop diuretics. 

Van Kimmenade said there was no signal of any benefit from fluid restriction either. “It is unlikely that fluid restriction would change outcomes for patients with more severe HF.”

Fluid monitoring difficult for patients

Van Kimmenade acknowledged that the study was inspired by patients. “They’re telling us: ‘You’re giving me this advice to restrict fluid intake, but how is this helping me?”

He said patients with HF did not like to keep track of how much they had drunk, nor decide whether they could have a cup of coffee in the morning or a cup of tea in the afternoon.

Not only is fluid monitoring difficult. Fluid restriction can also impact a patient’s QoL. Several studies have shown that fluid restriction is a risk factor for increased thirst distress in patients with HF. [Eur J Heart Fail;2013;15:141-149; J Cardiovasc Nurs 2020;35:19-25]

In the FRESH-UP study, thirst distress, measured using the Thirst Distress Scale, was significantly higher in the restricted-fluid group (18.6 points vs 16.9 points with liberal fluids; p<0.001).

Shifting focus

Invited discussant Dr Shelley Hall from Baylor University Medical Centre in Dallas, Texas, US, chair of the ACC Heart Failure and Transplant Council, said she was delighted to hear the results of the FRESH-UP trial.

“It's not just about whether patients live or die anymore. There are so many treatments improving mortality now that our focus needs to shift to QoL. It has become increasingly important,” she emphasized. “We have done such a good job with our interventions in HF that we need to start focusing on the QoL of our patients.”

Take-home messages

Regular fluid intake varies by age and sex. For healthy individuals, the average daily fluid intake is 3.46 L (14.6 cups) for men and about 2.75 L (11.6 cups) for women.

In FRESH-UP, reported fluid intakes among HF patients were approximately 1.76 L in the liberal group and 1.48 L in the restrictive group (p<0.001).

“One of the nice things about the results for us old-timers is that it validates our raised eyebrows when the [limit was raised] from 2 L to 1.5 L,” Hall said. “2 L is fine for most patients. Let’s be a little kinder to our patients and ourselves. We don't have to be so harsh in pounding fluid restriction.”

A good recommendation would be for patients to drink to quench their thirst, rather than whatever amount they want, Hall advised.