Liberal or Restricted Fluid Intake in Patients With Heart Failure (FLUID-HF)

February 20, 2026 updated by: Carolin Nymark, Region Stockholm

Liberal or Restricted Fluid Intake in Patients With Heart Failure: a Non-inferiority Randomized Controlled Trial

Heart failure is the most common cause of admission to hospital and is associated with high morbidity and mortality. Treatment options consist of medical- and device treatment and self-care strategies, where fluid restriction has been one of the components in the self-care management of patients with chronic heart failure. The medical treatment has progressed and improved over the years and considerably over the last few years, which has decreased symptoms and improved physical function of these patients. Despite our great success in the medical treatment of heart failure, we still face challenges in hospital readmissions and treatment strategies. It contributes to the increased need of evidence on, if and how, fluid intake and fluid restriction should be used as a self-care method. Fluid restriction as a self-care treatment is still commonly recommended in heart failure management although the scientific clinical evidence is lacking. Fluid restriction is associated with a higher degree of thirst and lower rated quality of life, and there is no consensus on how fluid restriction should be used, no plan for individualized treatment and no agreement on how fluid restriction should be a part of the patient self-care treatment. There is therefore a need for knowledge on how heart failure patients are affected by fluid restriction regarding clincal signs and symptoms of heart failure, quality of life, physical function, readmission to hospital or heart failure events. The primary aim of the study is to investigate whether a free fluid intake is safe compared to a restricted fluid intake, regarding clinical signs of heart failure measured as the presence of B-lines and/or an increase in NT-proBNP. The secondary aim is to clarify whether an unlimited fluid intake can improve quality of life and reduce thirst without affecting heart failure symptoms, physical activity, hospital readmissions and/or heart failure events.

Study Overview

Status

Status

Indicates the current recruitment status or the expanded access status.
Recruiting

Conditions

Conditions

The disease, disorder, syndrome, illness, or injury that is being studied. On ClinicalTrials.gov, conditions may also include other health-related issues, such as lifespan, quality of life, and health risks.

Intervention / Treatment

Intervention / Treatment

A process or action that is the focus of a clinical study. Interventions include drugs, medical devices, procedures, vaccines, and other products that are either investigational or already available. Interventions can also include noninvasive approaches, such as education or modifying diet and exercise.

Detailed Description

Heart failure is the most common cause of admission to hospital and is associated with high morbidity and mortality. Treatment options consist of medical- and device treatment and self-care strategies, where fluid restriction has been one of the components in the self-care management of patients with chronic heart failure. The medical treatment has progressed and improved over the years and considerably over the last few years, which has decreased symptoms and improved physical function of these patients. Despite the improvement in medical treatment, we still face challenges in readmission to hospital and in treatment strategies. It contributes to the increased need of evidence on, if and how, fluid intake and fluid restriction should be used as a self-care method. Fluid restriction as a self-care treatment is still commonly recommended in heart failure management although the scientific clinical evidence is lacking. Fluid restriction is associated with a higher degree of thirst and lower rated quality of life, and there is no consensus on how fluid restriction should be used, no plan for individualized treatment and no agreement on how fluid restriction should be a part of the patient self-care treatment. There is therefore a need for knowledge on how heart failure patients are affected by fluid restriction regarding quality of life, physical function, signs and symptoms and readmission to hospital.

Study Type

Study Type

Describes the nature of a clinical study. Study types include interventional studies (also called clinical trials), observational studies (including patient registries), and expanded access.
Interventional

Enrollment (Estimated)

Enrollment

The number of participants in a clinical study. The "anticipated" enrollment is the target number of participants that the researchers need for the study.
326

Phase

Phase

The stage of a clinical trial studying a drug or biological product, based on definitions developed by the U.S. Food and Drug Administration (FDA). The phase is based on the study's objective, the number of participants, and other characteristics. There are five phases: Early Phase 1 (formerly listed as Phase 0), Phase 1, Phase 2, Phase 3, and Phase 4. Not Applicable is used to describe trials without FDA-defined phases, including trials of devices or behavioral interventions.
  • Not Applicable

Contacts and Locations

This section provides the contact details for those conducting the study, and information on where this study is being conducted.

Study Contact

Study Contact

The name and contact information for the person who can answer enrollment questions for a clinical study. Each location where the study is being conducted may also have a specific contact, who may be better able to answer those questions.

Study Locations

Participation Criteria

Researchers look for people who fit a certain description, called eligibility criteria. Some examples of these criteria are a person's general health condition or prior treatments.

Eligibility Criteria

Eligibility Criteria

The key requirements that people who want to participate in a clinical study must meet or the characteristics they must have. Eligibility criteria consist of both inclusion criteria (which are required for a person to participate in the study) and exclusion criteria (which prevent a person from participating). Types of eligibility criteria include whether a study accepts healthy volunteers, has age or age group requirements, or is limited by sex.

Ages Eligible for Study

  • Adult
  • Older Adult

Accepts Healthy Volunteers

No

Description

Inclusion Criteria:

  • Diagnosed with left ventricual heart failure (HFrEF, HFmEF)
  • Physical, cognitive and linguistic ability to carry out all aspects of the study

Exclusion Criteria:

  • Reversible cause of HF (thyroid disorders, severe anemia, etc.)
  • Hyponatremia at baseline (sodium <130 mmol/L)
  • eGFR at baseline <30mL/min/1.73m2
  • Scheduled cardiac surgery, coronary intervention (percutaneous coronary intervention or coronary artery bypass graft surgery) within 3 months
  • Myocardial infarction within 3 months
  • Comorbidity for which fluid restriction or unlimited fluid intake is advised
  • Life expectancy <6 months

Study Plan

This section provides details of the study plan, including how the study is designed and what the study is measuring.

How is the study designed?

Design Details

  • Primary Purpose: Prevention
  • Allocation: Randomized
  • Interventional Model: Parallel Assignment
  • Masking: None (Open Label)

Arms and Interventions

Participant Group / Arm

Participant Group / Arm

A group or subgroup of participants in a clinical trial that receives a specific intervention/treatment, or no intervention, according to the trial's protocol.
Intervention / Treatment

Intervention / Treatment

A process or action that is the focus of a clinical study. Interventions include drugs, medical devices, procedures, vaccines, and other products that are either investigational or already available. Interventions can also include noninvasive approaches, such as education or modifying diet and exercise.
Experimental: Free fluid intake
Patients have no restrictions of fluid intake
Behavioral: Free fluid intake
Patients are recommended a free fluid intake
No Intervention: Restricted fluid intake
Patients are recommended a restricted fluid intake of 1500 mL/day

What is the study measuring?

Primary Outcome Measures

Primary Outcome Measures

In a clinical study's protocol, the planned outcome measure that is the most important for evaluating the effect of an intervention/treatment. Most clinical studies have one primary outcome measure, but some have more than one.
Outcome Measure
Measure Description
Time Frame
NT-proBNP
Time Frame: 12 weeks
Specific biomarkers for heart failure (blood test)
12 weeks
B-lines
Time Frame: 12 weeks
The patients will be investigated with lung ultrasound to screen for B-lines (comet tail artifacts) to assess pulmonary congestion
12 weeks

Secondary Outcome Measures

Secondary Outcome Measures

In a clinical study's protocol, a planned outcome measure that is not as important as the primary outcome measure for evaluating the effect of an intervention but is still of interest. Most clinical studies have more than one secondary outcome measure.
Outcome Measure
Measure Description
Time Frame
Heart failure symptoms
Time Frame: 12 weeks
Symptoms of heart failure measured by questionnaires
12 weeks
HRQoL
Time Frame: 12 weeks
Health related quality of life measured with EQ5D
12 weeks
Physical Capacity
Time Frame: 12 weeks
Physical Capacity measured by six minutes walktest
12 weeks
Hospital readmissions
Time Frame: 12 weeks
Hospital readmissions within three months
12 weeks
Thirst distress
Time Frame: 12 weeks
12 weeks
Self-Care
Time Frame: 12 weeks
Self-care in chronic illness, measured by a questionnaire
12 weeks
IVC
Time Frame: 12 weeks
Ultrasound of Inferior Vena Cava (IVC) diameter and respiratory variation.
12 weeks
Pleural effusion
Time Frame: 12 weeks
Lungultrasound with screening for pleural effusion
12 weeks
Heart failure events
Time Frame: 12 weeks
Contact with helathcare due to heart failure symtoms, increased use of diuretics with/without admission etc.
12 weeks

Collaborators and Investigators

This is where you will find people and organizations involved with this study.

Sponsor

Sponsor

The organization or person who initiates the study and who has authority and control over the study.
Region Stockholm

Collaborators

Collaborators

An organization other than the sponsor that provides support for a clinical study. This support may include activities related to funding, design, implementation, data analysis, or reporting.
Capio Sankt Görans Hospital
Ersta Hospital, Sweden

Investigators

Investigators

A researcher involved in a clinical study. Related terms include site principal investigator, site sub-investigator, study chair, study director, and study principal investigator.
  • Principal Investigator: Carolin Nymark, PhD, Karolinska Universitetssjukhuset, Heart and Vascular Center

Study record dates

These dates track the progress of study record and summary results submissions to ClinicalTrials.gov. Study records and reported results are reviewed by the National Library of Medicine (NLM) to make sure they meet specific quality control standards before being posted on the public website.

Study Major Dates

Study Start (Actual)

Study Start

The actual date on which the first participant was enrolled in a clinical study. The "anticipated" study start date is the date that the researchers think will be the study start date.
February 14, 2024

Primary Completion (Estimated)

Primary Completion

The date on which the last participant in a clinical study was examined or received an intervention to collect final data for the primary outcome measure. Whether the clinical study ended according to the protocol or was terminated does not affect this date. For clinical studies with more than one primary outcome measure with different completion dates, this term refers to the date on which data collection is completed for all the primary outcome measures. The "anticipated" primary completion date is the date that the researchers think will be the primary completion date for the study.
December 1, 2028

Study Completion (Estimated)

Study Completion

The date on which the last participant in a clinical study was examined or received an intervention/treatment to collect final data for the primary outcome measures, secondary outcome measures, and adverse events (that is, the last participant's last visit). The "anticipated" study completion date is the date that the researchers think will be the study completion date.
December 1, 2028

Study Registration Dates

First Submitted

First Submitted

The date on which the study sponsor or investigator first submitted a study record to ClinicalTrials.gov. There is typically a delay of a few days between the first submitted date and the record's availability on ClinicalTrials.gov (the first posted date).
June 16, 2023

First Submitted That Met QC Criteria

First Submitted That Met QC Criteria

The date on which the study sponsor or investigator first submits a study record that is consistent with National Library of Medicine (NLM) quality control (QC) review criteria. The sponsor or investigator may need to revise and submit a study record one or more times before NLM's QC review criteria are met. It is the responsibility of the sponsor or investigator to ensure that the study record is consistent with the NLM QC review criteria.
June 27, 2023

First Posted (Actual)

First Posted

The date on which the study record was first available on ClinicalTrials.gov after National Library of Medicine (NLM) quality control (QC) review has concluded. There is typically a delay of a few days between the date the study sponsor or investigator submitted the study record and the first posted date.
July 5, 2023

Study Record Updates

Last Update Posted (Actual)

Last Update Posted

The most recent date on which changes to a study record were made available on ClinicalTrials.gov. There may be a delay between when the changes were submitted to ClinicalTrials.gov by the study's sponsor or investigator (the last update submitted date) and the last update posted date.
February 24, 2026

Last Update Submitted That Met QC Criteria

Last Update Submitted That Met QC Criteria

The most recent date on which the study sponsor or investigator submitted changes to a study record that are consistent with National Library of Medicine (NLM) quality control (QC) review criteria. It is the responsibility of the sponsor or investigator to ensure that the study record is consistent with the NLM QC review criteria.
February 20, 2026

Last Verified

Last Verified

The most recent date on which the study sponsor or investigator confirmed the information about a clinical study on ClinicalTrials.gov as accurate and current. If a study with a recruitment status of recruiting; not yet recruiting; or active, not recruiting has not been confirmed within the past 2 years, the study's recruitment status is shown as unknown.
February 1, 2026

More Information

Terms related to this study

Keywords

Additional Relevant MeSH Terms

Other Study ID Numbers

Other Study ID Numbers

Identifiers or ID numbers other than the NCT number that are assigned to a clinical study by the study's sponsor, funders, or others. These numbers may include unique identifiers from other trial registries and National Institutes of Health grant numbers.
  • K 2023-3124

Plan for Individual participant data (IPD)

Plan to Share Individual Participant Data (IPD)?

NO

Drug and device information, study documents

Studies a U.S. FDA-regulated drug product

No

Studies a U.S. FDA-regulated device product

No

product manufactured in and exported from the U.S.

No

This information was retrieved directly from the website clinicaltrials.gov without any changes. If you have any requests to change, remove or update your study details, please contact register@clinicaltrials.gov. As soon as a change is implemented on clinicaltrials.gov, this will be updated automatically on our website as well.

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