Restrictive Versus Liberal Fluid Intake in Acute Decompensated Heart Failure (RELIEF-AHF)

Restrictive Versus Liberal Fluid Intake in Acute Decompensated Heart Failure: a Randomized Trial

The aim of this clinical trial is to learn whether a thirst-driven, liberal fluid-intake strategy is comparable to a fluid-restriction strategy in patients hospitalized for acute decompensated heart failure (ADHF). The study will also assess the safety of the intervention and its effects on thirst and quality of life.

Patients hospitalized with ADHF will be asked to follow either a thirst-driven fluid-intake strategy or a fluid-restriction strategy during their hospital stay and for one month after discharge.

Study Overview

• Status: Recruiting
• Conditions: Acute Heart Failure (AHF)
• Intervention / Treatment: Behavioral: Thirst-driven, liberal fluid intake; Behavioral: Fluid restriction strategy

• Study Type: Interventional
• Enrollment (Estimated): 420
• Phase: Not Applicable

Contacts and Locations

• Study Contact: Name: Anders Hostrup Larsen, MD, PhD; Phone Number: 0045; Email: anders.hostrup@rm.dk

Study Locations

• Denmark
  • Herning, Denmark, 7400
    • Recruiting
    • Department of Cardiology, Gødstrup Hospital
    • Contact: Anders Hostrup Larsen, MD, PhD; Phone Number: 0045; Email: anders.hostrup@rm.dk

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: Adult; Older Adult
• Accepts Healthy Volunteers: No

Description

Inclusion Criteria:

1. Age >18 years

2. Hospitalized for ADHF as the primary diagnosis, meeting both of the following:

   1. ≥1 documented symptom of new or worsening heart failure (dyspnea, fatigue, decreased exercise tolerance, or symptom of end-organ hypoperfusion).
   2. Objective evidence of ADHF, defined as either:

   i. ≥2 physical signs (edema, ascites, pulmonary rales/crackles, increased JVP, S3 gallop, rapid weight gain due to fluid retention), OR ii. ≥1 physical sign AND ≥1 laboratory finding indicative of ADHF (BNP >500 ng/L or NT-proBNP >2000 ng/L if sinus rhythm, or BNP >750 ng/L or NT-proBNP >3000 ng/L if atrial fibrillation, radiological/ultrasound evidence of pulmonary congestion, echocardiographic sign [VCI >2.1 cm, LVOT VTI <15 cm, E/e' >14, D-dominant pulmonary venous inflow pattern], or invasive evidence [CVP >12 mmHg, PCWP >18 mmHg, CI <2.2 L/min/m2]).

3. Treatment with ≥40 mg IV furosemide (or equivalent)
4. Enrolment within 24 hours of admission
5. Ability to provide informed consent

Exclusion Criteria:

1. Requirement at admission for ICU-level care, or IV inotropic/vasopressor therapy for ADHF.
2. Na+ <125 mmol/L or Na+ >145 mmol/L.
3. End-stage chronic kidney disease on chronic dialysis or eGFR <15 mL/min/1.73 m2
4. Any condition which would make participation unsafe or substantially affect protocol adherence, as judged by investigator.

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Treatment
• Allocation: Randomized
• Interventional Model: Parallel Assignment
• Masking: Single

Number of Arms

2

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Experimental: Thirst-driven, liberal fluid intake	Behavioral: Thirst-driven, liberal fluid intake; Liberal fluid intake driven by thirst without restrictions
Active Comparator: Fluid restriction	Behavioral: Fluid restriction strategy; Fluid restriction of 1.5 L/day

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Time to clinical stability	Time from randomization to clinical stability. Clinical stability is defined as: Off IV loop diuretics for ≥ 24 hours without need for reinitiation of IV diuretics.; No evidence of pulmonary congestion, defined as both:i) No new or worsening dyspnea at rest compared with status at admission ii) Clear lung auscultation or clinically improved, or normal lung and/or vena cava ultrasound without evidence of congestion.; No new or worsening peripheral edema compared with status at admission.	From enrollment to 1 month follow-up

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Thirst Distress	Thirst Distress Scale for patients with Heart Failure (TDS-HF). Scores range from 8 to 40. Higher scores indicate greater thirst-related distress	From enrollment to 1 month follow up
Patient-perceived Quality of Life	Kansas City Cardiomyopathy Questionnaire (KCCQ). Scores range from 0 to 100, with higher scores indicating better health status.	From enrollment to 1 month follow up
Incidence of Treatment-Emergent Adverse Events (Safety and Tolerability)	Number of occurrences during hospitalization of clinical worsening (escalation of HF therapy, such as vasopressor/inotrope initiation, ICU transfer, dialysis, reinitiation of IV diuretics), electrolyte disturbances, worsening renal function, or in-hospital death, and similarly after one month including HF hospitalization	From enrollment to 1 month follow up

Collaborators and Investigators

• Sponsor: Gødstrup Hospital

Study record dates

Study Major Dates

• Study Start (Actual): May 1, 2026
• Primary Completion (Estimated): May 1, 2029
• Study Completion (Estimated): August 1, 2029

Study Registration Dates

• First Submitted: February 3, 2026
• First Submitted That Met QC Criteria: February 3, 2026
• First Posted (Actual): February 10, 2026

Study Record Updates

• Last Update Posted (Actual): May 7, 2026
• Last Update Submitted That Met QC Criteria: May 4, 2026
• Last Verified: February 1, 2026

More Information

Terms related to this study

• Keywords: Acute heart failure; Fluid Restriction; Thirst-driven fluid intake; Liberal fluid intake; Time to clinical stability
• Other Study ID Numbers: 1-16-02-56-26

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: UNDECIDED
• IPD Plan Description: Due to regulations by Region Committees on Health Research Ethics

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No