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

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: Recruiting
• Conditions: Heart Failure
• Intervention / Treatment: Behavioral: Free fluid intake

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: Interventional
• Enrollment (Estimated): 326
• Phase: Not Applicable

Contacts and Locations

• Study Contact: Name: Carolin Nymark, PhD; Phone Number: +46725955887; Email: carolin.nymark@ki.se

Study Locations

• Sweden
  • Stockholm, Sweden, 17176
    • Recruiting
    • Karolinska University Hospital
    • Contact: Carolin Nymark, PhD; Phone Number: +46725955887; Email: carolin.nymark@regionstockholm.se

Participation Criteria

Eligibility Criteria

• 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

How is the study designed?

Design Details

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

Number of Arms

2

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
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

Outcome Measure	Measure Description	Time Frame
NT-proBNP	Specific biomarkers for heart failure (blood test)	12 weeks
B-lines	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

Outcome Measure	Measure Description	Time Frame
Heart failure symptoms	Symptoms of heart failure measured by questionnaires	12 weeks
HRQoL	Health related quality of life measured with EQ5D	12 weeks
Physical Capacity	Physical Capacity measured by six minutes walktest	12 weeks
Hospital readmissions	Hospital readmissions within three months	12 weeks
Thirst distress		12 weeks
Self-Care	Self-care in chronic illness, measured by a questionnaire	12 weeks
IVC	Ultrasound of Inferior Vena Cava (IVC) diameter and respiratory variation.	12 weeks
Pleural effusion	Lungultrasound with screening for pleural effusion	12 weeks
Heart failure events	Contact with helathcare due to heart failure symtoms, increased use of diuretics with/without admission etc.	12 weeks

Collaborators and Investigators

• Sponsor: Region Stockholm
• Collaborators: Capio Sankt Görans Hospital; Ersta Hospital, Sweden
• Investigators: Principal Investigator: Carolin Nymark, PhD, Karolinska Universitetssjukhuset, Heart and Vascular Center

Study record dates

Study Major Dates

• Study Start (Actual): February 14, 2024
• Primary Completion (Estimated): December 1, 2028
• Study Completion (Estimated): December 1, 2028

Study Registration Dates

• First Submitted: June 16, 2023
• First Submitted That Met QC Criteria: June 27, 2023
• First Posted (Actual): July 5, 2023

Study Record Updates

• Last Update Posted (Actual): February 24, 2026
• Last Update Submitted That Met QC Criteria: February 20, 2026
• Last Verified: February 1, 2026

More Information

Terms related to this study

• Keywords: Quality of life; Heart failure; Lung ultrasound; B-lines; Hospital readmissions; Intervention; Fluid restriction; Physical capacity; Symptoms; Fluid intake; NT-ProBNP; Thirst distress
• Additional Relevant MeSH Terms: Cardiovascular Diseases; Heart Diseases; Heart Failure
• Other Study ID 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