Iron before heart surgery cut transfusions but bought one extra day at home
ITACS randomised 955 anaemic adults to intravenous iron or placebo before elective cardiac surgery. Fewer patients needed a transfusion, but the primary benefit was a median of one day alive and at home.
| Group | Value (%) |
|---|---|
| Intravenous iron | 61.1 |
| Placebo | 68.2 |
Anaemia is common in people waiting for heart surgery, and it predicts a rockier recovery: more transfusions, longer stays, more complications. Correcting the iron deficiency that often underlies it seems an obvious fix, and iron infusions are already used in some blood-management programmes on that logic. But observational links between anaemia and poor outcomes do not prove that topping up iron beforehand changes them — the anaemia may be a marker of sicker patients rather than the thing driving the harm. ITACS, published in the BMJ on 19 August, is the largest randomised test of whether treating it changes what matters to patients [s1]. The answer is a qualified one.
ITACS was an international, double-blind, placebo-controlled randomised trial run at 33 hospitals across 10 countries, enrolling participants between July 2016 and December 2023 [s1]. It randomised 955 adults with anaemia who were scheduled for elective cardiac surgery to a single 1000 mg dose of intravenous iron or to placebo, given between 1 and 26 weeks before the operation [s1]. Participants, clinicians and data collectors were all masked to which infusion a patient received [s1]. The trial was sponsored by Bayside Health with funding from Australia's National Health and Medical Research Council and Monash University, and lists no commercial sponsor [s2].
What the trial measured
The designers chose a patient-centred primary outcome rather than a laboratory one: the number of days a person was alive and at home in the 90 days after surgery [s1]. It is a composite that captures death, prolonged admission and readmission in a single count, and it is harder to move than a blood test.
Of 2,993 people screened, 955 were enrolled, and 921 of the 939 eligible modified intention-to-treat participants were assessed for the primary outcome [s1]. The median number of days alive and at home was 81.1 (interquartile range 74.8 to 83.7) in the iron group and 80.0 (69.5 to 83.6) in the placebo group [s1]. The adjusted median difference was 1.0 day, with a 95.4% confidence interval running from 0.0 to 2.1 days and a P value of 0.041 [s1]. The result cleared the conventional threshold for statistical significance, but only just, and the lower bound of the interval sits on zero.
The transfusion finding was cleaner. A red cell transfusion was given during the hospital stay to 262 patients (61.1%) in the iron group and 302 (68.2%) in the placebo group, a relative risk of 0.90 (95% confidence interval 0.82 to 0.99, P=0.027) [s1]. No differences were seen for major complications or for length of hospital stay [s1].
How to read a one-day difference
A single day at home over three months is a small effect, and it is worth being plain about that rather than dressing it up. The trial's own authors frame intravenous iron as an effective component of patient blood management in this setting, resting the case mainly on the drop in transfusions rather than on the primary endpoint [s1]. That is a defensible reading: transfusions carry their own risks and costs, and cutting them by roughly a tenth in relative terms across a large surgical population is not trivial.
But the primary outcome is the number the trial was built to answer, and on that measure the benefit is at the edge of detectability. Readers should be wary of coverage that leads with "iron speeds recovery after heart surgery" without noting that the recovery in question amounts to a median of one day, on an interval that touches zero [s1]. The trial does not show that iron prevents deaths or serious complications; it was not powered to, and it did not [s1].
There are limits worth stating. The enrolment window stretched across more than seven years, during which transfusion practice itself has grown more conservative [s1]. The single fixed dose and the wide pre-surgery timing window mean the trial tests one strategy, not the full range of ways iron might be given. And a composite like days alive and at home, while patient-relevant, can be pushed by any of its components without telling a reader which one moved.
What to watch
ITACS registered on ClinicalTrials.gov as NCT02632760, and its full protocol and pre-specified analyses are logged there for anyone checking the numbers against the plan [s2]. The practical question now is one of value: whether a modest, mostly transfusion-driven benefit justifies routinely infusing iron into anaemic patients weeks before surgery, and in which patients the effect is largest. Guideline committees weighing blood-management programmes will have to decide how much weight a one-day median difference can bear.
Sources
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