Fluid restriction does not improve health in heart failure patients

People with heart failure have long been advised to limit the amount of fluids they consume each day to help reduce congestion, or the buildup of fluid in the lungs and extremities, but that advice provides no benefit, according to a study presented at the American College of Cardiology’s Annual Scientific Session (ACC.25).

Heart failure occurs when the heart becomes too stiff or too weak to effectively pump blood throughout the body. Congestion is a common symptom that can cause swelling and shortness of breath. To help reduce this, U.S. and European medical guidelines recommend limiting daily fluid intake to about six cups (1,500 milliliters). However, evidence for this recommendation is lacking and experts have debated whether restricting fluid intake is necessary.

This study is the first large randomized controlled trial to evaluate how liberal versus restricted fluid intake impacts health status in patients with heart failure. The results showed a trend toward improved health status for those with unrestricted fluid intake but the difference between study groups was not statistically significant for the study’s primary endpoint. Thirst was higher in those with fluid restriction, while there was no difference in any of the exploratory safety outcomes.

Our conclusion is that in patients with stable heart failure there is no need for fluid restriction. This is an important message to heart failure patients all over the world and can be implemented immediately.”

Roland van Kimmenade, MD, cardiologist at Radboud University Medical Center in Nijmegen, Netherlands, and study’s senior author

The trial, called FRESH-UP, enrolled 504 people with heart failure at seven medical centers in the Netherlands. Study participants were 69 years old on average, about two-thirds were men, and all had heart failure with mild to moderate symptoms but were comfortable at rest. About half of the participants had heart failure with reduced ejection fraction and half had preserved ejection fraction, representing the two types of heart failure. Most participants were taking standard heart failure medications and about half were taking loop diuretics, a type of drug that helps to manage swelling and fluid retention.

Half of the participants were assigned to limit their daily fluid intake to 1,500 mL and half were instructed to drink as much as they wished. At three months, researchers assessed participants’ health status using the Kansas City Cardiomyopathy Questionnaire (KCCQ) and found no statistically significant difference between groups.

Researchers said that several factors may have affected the results. One unforeseen finding was that about half of the patients had not been advised to limit their fluid intake before enrolling in the study. Second, participants had higher scores for health status at baseline than expected. Given that the study population had a relatively high baseline health status and many were already on a regimen of liberal fluid intake, it was challenging for the study to demonstrate a significant benefit from liberal fluid intake versus fluid restriction. According to the researchers, this may have led to the non-significant results of the primary outcome.

Overall, the difference in fluid intake between the two groups was relatively modest. Patients assigned to fluid restriction consumed an average of 1,480 mL per day and those assigned to unrestricted fluid intake consumed an average of 1,760 mL per day, an average difference of less than 10 ounces. Participants assigned to restrict their fluid intake reported more thirst. Importantly, there were no differences between groups in terms of death, heart failure hospitalizations, need for intravenous diuretics or acute kidney injury at six months.

“We did not find any signal in the primary or safety outcomes that fluid restriction contributes to anything or that liberal fluid intake would lead to any harm,” van Kimmenade said. “Accordingly, our results question the need for fluid restriction in patients with stable heart failure.”

Although the study was conducted in a single country, researchers said that the findings would likely be generalizable to other developed countries where some clinicians routinely advise fluid restriction for patients with heart failure and others do not.

The study was funded by the Dutch Heart Foundation and a Radboud UMC /Maastricht UMC inter-university grant.

This study was simultaneously published online in Nature Medicine at the time of presentation.