Reduction of to less than 100 mmol in heart failure (SODIUM-HF): an international, open-label, randomised, controlled trial

Heart failure (HF) is associated with abnormalities leading to sodium and water retention, hence reduction of sodium intake has been suggested as an approach to prevent fluid overload and adverse clinical outcomes but high-quality results from large trials are missing.

The SODIUM-HF trial aimed to investigate the effects of dietary sodium reduction on clinical outcomes in patients with HF.

This study was the largest and longest trial to test a strategy of dietary sodium reduction for ambulatory patients with HF.

A low sodium diet didn’t improve clinical endpoints however, it may improve quality of life and New York Heart Association (NYHA) functional class. 

SODIUM-HF is an international, open-label, randomised, controlled trial (NCT02012179). Patients were enrolled across six countries and assigned to either the low sodium treatment arm and had a sodium target of 1500 mg/day, or the usual care treatment arm and received a general advice on restricting sodium intake.  

• Composite of cardiovascular related hospitalisation, cardiovascular-related emergency department visit, and all-cause death within 12 months after randomisation

• Time to first event within the event type within 12 and 24 months
• Quality of life as measured via the Kansas City Cardiomyopathy Questionnaire (KCCQ) overall summary score
• Clinical summary score
• Physical limitation score
• Change in 6-min walk distance
• Change in NYHA functional class

• 18 years or older
• Chronic HF (defined as NYHA functional class 2–3)
• Receiving optimally tolerated guideline-directed medical therapy

• Average dietary sodium intake < 1500 mg/day  
• Serum sodium concentration < 130 mmol/L
• An estimated glomerular filtration rate < 20 mL/min per 1·73 m² or haemodialysis-dependent renal failure
• Admission to hospital for a cardiovascular cause in the past month

• 806 patients were randomly assigned to a low sodium diet or usual care
• From baseline to 12 months, the median sodium intake decreased from 2286 mg/day to 1658 mg/day in the low sodium treatment arm and from 2119 y - 2073 mg/day in the usual care treatment arm with the median difference of 415 mg/day at 12 months (p<0.0001)
• Within 12 months, in the low sodium treatment vs usual care treatment arms respectively:
  • 15% vs. 17% experienced the primary endpoint [Hazard ratio (HR), 0.89; 95% confidence interval (CI), 0.63–1.26]
  • 6% vs. 4% of patients had all-cause death (HR, 1.38; 95% CI, 0.73–2.60; p=0·32)
  • 10% vs. 12% experienced cardiovascular-related hospitalisation (HR, 0.82; 95% CI, 0.54 –1.24; p=0·36)
  • 4% vs. 4% of patients had cardiovascular-related emergency department visits (HR, 1·21; 95% CI, 0·60–2·41; p=0·60)
• Within 12 months, the increases in the overall summary score, the clinical summary score, and the physical limitation score on the KCCQ were significantly greater in the low sodium diet treatment arm than in the usual care treatment arm
• There was a significantly greater likelihood of improving NYHA class with the low sodium treatment arm (odds ratio, 0.59; 95% CI, 0.40–0.86; p=0.0061)
• No significant differences in other secondary endpoints or safety events were reported

SODIUM-HF delivers an update to current evidence and ascertains that in ambulatory patients with HF a dietary intervention was feasible and effective in reducing sodium intake but did not have an impact on the clinical outcomes. There were, however, small improvements in quality of life and NYHA functional class. 

• Patients were not blinded to the assigned treatment
• Patients in the usual care treatment arm may have chosen to reduce their sodium intake
• No data or urinary biomarkers were collected
• The trial was concluded early