By Bianca Nogrady
A US randomised clinical trial has failed to find any improvement in exercise capacity associated with oral iron supplementation in iron-deficient patients with heart failure.
Writing in JAMA, researchers reported the results of a double-blind, placebo-controlled study in which 225 patients with reduced left ventricular ejection fraction and iron deficiency were randomised either to 150 mg of oral iron polysaccharide, twice daily for 16 weeks, or placebo.
The study showed no significant differences between the two groups in changes in peak oxygen uptake at 16 weeks, regardless of gender, haemoglobin levels, venous congestion or peak respiratory exchange ratio.
Researchers also saw no significant differences in changes in six-minute walk distance, ventilatory efficiency, plasma N-terminal pro-B type natriuretic peptide levels or health status according to the Kansas City Cardiomyopathy Questionnaire. However, oral iron was associated with increased hepcidin, transferrin saturation and ferritin levels.
The authors noted that their results contrasted with studies of intravenous iron supplementation in similar patient populations.
‘Also in contrast to previous studies with intravenous iron repletion, in this study, oral iron therapy produced minimal improvement in iron stores, implicating the route of administration rather than the strategy of iron repletion in the lack of clinical benefit,’ they wrote.
Associate Professor Jo-Dee Lattimore said it was a disappointing result from a well-conducted trial. ‘It’s always sad when a simple solution like oral iron doesn’t work, because we want the simple inexpensive things to work,’ said Professor Lattimore, a cardiologist at Sydney’s Royal Prince Alfred Hospital.
Absorption of oral iron presented a challenge, Associate Professor Lattimore told Cardiology Today, but that meant other forms of iron may still be an option.
‘It needs more studies to be more robust but it certainly doesn’t take intravenous iron out of the equation at this point in time,’ she said.
The authors also suggested that a longer trial or one using a higher dose of oral iron may have found beneficial effects, particularly in patients with low hepcidin levels.
JAMA 2017; 317: 1958-1966.
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