Effect of fluid and dietary sodium restriction in the management of patients with heart failure and preserved ejection fraction: study protocol for a randomized controlled trial

BACKGROUND Although half of all patients with heart failure (HF) have a normal or near-normal ejection fraction and their prognosis differs little from that of patients with a reduced ejection fraction, the pathophysiology of HF with preserved ejection fraction (HF-PEF) is still poorly understood, and its management poorly supported by clinical trials. Sodium and fluid restriction is the most common self-care measure prescribed to HF patients for management of congestive episodes. However, its role in the treatment of HF-PEF remains unclear. This trial seeks to compare the effects of a sodium- and fluid-restricted diet versus an unrestricted diet on weight loss, neurohormonal activation, and clinical stability in patients admitted for decompensated HF-PEF. METHODS/DESIGN This is a randomized, parallel trial with blinded outcome assessment. The sample will include adult patients (aged ≥18 years) with a diagnosis of HF-PEF admitted for HF decompensation. The patients will be randomized to receive a diet with sodium and fluid intake restricted to 0.8 g/day and 800 mL/day respectively (intervention group) or an unrestricted diet, with 4 g/day sodium and unlimited fluid intake (control group), and followed for 7 days or until hospital discharge. The primary outcome shall consist of weight loss at 7 days or discharge. The secondary outcome includes assessment of clinical stability, neurohormonal activation, daily perception of thirst and readmission rate at 30 days. DISCUSSION Assessment of the effects of sodium and fluid restriction on neurohormonal activation and clinical course of HF-PEF can promote a deeper understanding of the pathophysiology and progression of this complex syndrome. TRIAL REGISTRATION NUMBER ClinicalTrials.gov identifier: NCT01896908 (date of registration: 8 August 2013).