One-of-a-Kind Clinical Trial of Sodium Intake in Acute Heart Failure Patients Challenges Conventional Wisdom

Findings of OSPREY-AHF presented recently at Heart Failure Society of America meeting

Innovations in Cardiovascular Medicine & Surgery | Fall 2022

Dietary sodium restriction has been a mainstay of treatment for heart failure (HF) since the 1940s. However, new evidence from a placebo-controlled, randomized, double-blinded clinical trial of sodium in hospitalized HF patients – the first such trial of its kind – suggests that rethinking this approach may be warranted.

Robert Montgomery, MD

Robert Montgomery, MD, a heart failure specialist at University Hospitals Harrington Heart & Vascular Institute, recently presented results of the Oral Sodium to Preserve Renal Efficiency in Acute Heart Failure (OSPREY-AHF) trial at the annual meeting of the Heart Failure Society of America as a late-breaking clinical trial. In this trial, Dr. Montgomery and the research team randomly assigned 65 patients hospitalized with acute decompensated HF to 6 grams oral sodium chloride (NaCl) or placebo during intravenous diuretic therapy with furosemide over 96 hours, then measuring any change in the participants’ weight or kidney function.

Why Study Oral Sodium in HF?

The inspiration for this groundbreaking trial came from the literature on the potential benefit of adding hypertonic saline for hospitalized HF patients undergoing diuresis, Dr. Montgomery says.

“Some data supports giving NaCl in the form of hypertonic saline to decrease Renin-Angiotensin-Aldosterone System (RAAS) activation, decrease renal sodium avidity and increase diuretic response,” he says. “Numerous studies demonstrate that sodium restriction is associated with increased RAAS activation as well as increases in inflammatory markers. These findings challenge of the role of sodium restriction in hospital management of heart failure and have led to trials that consider a therapeutic role of providing sodium to patients with acute heart failure for its effect in attenuating neurohormonal activation during aggressive diuresis. With our study, we were looking to translate any potential benefits from the hypertonic saline literature to see what oral sodium could do.”

Dr. Montgomery says the OSPREY-AHF research team was also motivated by the relative lack of evidence and guideline support for sodium restriction in acute HF patients.

“Society guidelines have eased off on giving any recommendations for sodium restriction in acute heart failure,” he says. “When it comes to sodium restriction and heart failure, there is a gap in our evidence despite how widespread the practice is. In addition, randomized clinical trial data has shown that dietary sodium restriction in patients hospitalized with heart failure is not associated with differences in weight, clinical congestion or time to clinical stability.”

OSPREY-AHF Findings

Results from OSPREY-AHF showed no differences in weight or creatinine measurements for patients receiving oral sodium chloride vs. placebo, Dr. Montgomery says.

“Both groups, on average, lost weight, and both groups experienced a slight rise in their creatinine,” he says. “There was a difference in serum sodium, where it basically didn't change in the NaCl group, but it decreased on the placebo group. Blood urea nitrogen (BUN) increased in both groups, but increased more significantly in the placebo group.”

Although OSPREY-AHF results did not confirm findings seen in other studies with hypertonic saline, Dr. Montgomery says there is still much to be learned from the null result.

“The null result challenges our practice of NaCl restriction in acute HF, which is something prescribed thousands of times a day and millions of times a year,” he says. “And while our study was underpowered, the absence of demonstrable harm to NaCl during diuretic therapy suggests that larger clinical trials are possible and necessary.”

What Trial Results Mean for Clinical Practice

In the meantime, Dr. Montgomery says he hopes providers treating patients with acute HF will use the results of OSPREY-AHF to redouble their focus on strategies proven to be effective.

“There are things that we know work really, really well for heart failure,” he says. “We don't devote the same energy and resources to that as we do to sodium restriction. Patients who can’t keep up with the diet are labeled as non-compliant, difficult patients. I think it's much more important to ask about nutritional quality and barriers to healthy food in general, or to spend that time counselling on medication adherence. We should probably allocate resources to efforts like those and reallocate them away from dietary sodium restriction until we know it actually benefits patients. The bottom line is that the literature around sodium restriction is not as settled as many take for granted, and the choice of dietary restrictions of sodium in patients with acute heart failure may not be as beneficial as we think.”

Contributing Expert:
Robert Montgomery, MD
Heart Failure Specialist
University Hospitals Harrington Heart & Vascular Institute