Iron Infusion Boosts Exercise Capacity in Heart Failure
A single intravenous iron dose improved exercise capacity in heart failure patients with preserved ejection fraction and iron deficiency.
Updated on Nov. 9, 2026 in Heart Disease
A randomized trial found that one intravenous iron infusion improved exercise capacity in patients with heart failure with preserved ejection fraction and iron deficiency. The findings were published in Circulation and presented at the American Heart Association meeting.
Why it matters
Heart failure with preserved ejection fraction is difficult to treat, and the results suggest iron deficiency may be a modifiable contributor to reduced exercise capacity. Because oral iron has not benefited heart failure patients in prior studies, intravenous delivery offers a different treatment route for clinicians to consider.
In the 65-person IRON-MET HFpEF trial, peak VO2 rose about 10% at 12 weeks in the 44 patients given a single 1,000-mg IV dose of ferric derisomaltose, while it was unchanged in the 21 placebo patients. Longer-term durability and benefits in more diverse populations have not yet been established.
The players
Mass General Brigham Heart and Vascular Institute
A Boston-based cardiovascular research and clinical institution where the investigators conducted the IRON-MET HFpEF study.
Harvard Medical School
The Boston-based medical school whose affiliated investigators, including the lead and senior authors, led the trial.
The details
Participants with symptomatic HFpEF and iron deficiency, with a median age of 68 and 72% women, underwent cardiopulmonary exercise testing before and 12 weeks after infusion. Iron improved blood iron bioavailability, 6-minute walk distance, anaerobic-threshold VO2, and NYHA functional class relative to placebo, though patient-reported health scores did not differ significantly and no serious adverse events were linked to supplementation.
Timeline
November 8, 2026: Findings published in Circulation and presented at the American Heart Association meeting.
12 weeks: Follow-up exercise testing after infusion showed improved VO2.
Health Landscape
The IRON-MET trial builds on earlier negative results for oral iron in heart failure, shifting attention to intravenous delivery as a way around poor gut absorption. It fits a broader push to treat HFpEF, a condition with limited proven therapies, by addressing modifiable factors like iron deficiency.
For people with heart failure and iron deficiency, the findings suggest intravenous iron may improve exercise tolerance, but it is not yet a standard treatment. Patients should discuss iron testing and options with their cardiologist, as long-term benefits and broader safety data remain under study.
The takeaway
Iron deficiency is a treatable factor in some heart failure patients, and testing for it may be worthwhile. Larger, longer studies will determine whether intravenous iron changes outcomes that matter most to patients.
What happens next
The next step is a study to determine whether intravenous iron can improve long-term clinical outcomes in HFpEF patients.
Further reading
Explore more on Heart Disease in the United States.
More information
Read the Circulation journal article on the IRONMET-HFpEF trial.
Source note: This article includes information reported by News-Medical.
