The recently published PREFER study highlights a number of points, both old and new. It has been recognised for some time that pre-menopausal women suffer from fatigue. It has been assumed that much of this is due to mild anaemia secondary to iron deficiency.
In recent times, however, there has been some interest in the possible effects of correcting iron deficiency independent of any change in haemoglobin. This was highlighted in the FAIR-HF study of intravenous iron in heart failure1, and also in the recently published study of intravenous iron therapy in pulmonary arterial hypertension2. The PREFER study also contributes to the concept that correcting iron deficiency may have benefits above and beyond any change in haemoglobin.
The study demonstrated a significant improvement in fatigue, as assessed by the Piper Fatigue Scale, following a single administration of intravenous ferric carboxymaltose to iron-deficient pre-menopausal women, even in those without significant anaemia. This suggests that iron deficiency contributes to fatigue in these patients independent of any change in haemoglobin. As such, this study provides further randomised controlled evidence for positive effects of intravenous iron in non-anaemic iron-deficient subjects.
Interestingly, there were improvements in fatigue in the PREFER study in some subjects following the placebo injection. This demonstrates the importance of having a placebo group in studies examining a soft endpoint such as fatigue. In the PREFER study, however, the improvement following intravenous iron was significantly greater than placebo.
Globally, there is a huge number of pre-menopausal woman who potentially suffer from mild anaemia, iron deficiency, and fatigue, and the PREFER study indicates a possible role for intravenous iron in patients who are intolerant of oral iron, or where this treatment has proved ineffective.
The full article is available in the April 2014 issue of PLoS One. For a brief summary of the key points from the article, please click here.