Iron Deficiency in PREVENTT

We congratulate Toby Richards and colleagues1Richards T Baikady RR Clevenger B et al.Preoperative intravenous iron to treat anaemia before major abdominal surgery (PREVENTT): a randomised, double-blind, controlled trial.Lancet. 2020; 396: 1353-1361Summary Full Text Full Text PDF PubMed Scopus (49) Google Scholar for concluding the PREVENTT study, which sought to reduce the need for blood transfusion by giving preoperative intravenous iron to patients with anaemia before elective major abdominal surgery. Strategies to prevent transfusion need to be recognised and appropriately evaluated. The findings showed that preoperative iron infusion did not reduce the need for red blood cell transfusions; however, we disagree with the conclusion drawn that preoperative iron should not be recommended. Despite not selecting patients specifically for iron deficiency, Richards and colleagues1Richards T Baikady RR Clevenger B et al.Preoperative intravenous iron to treat anaemia before major abdominal surgery (PREVENTT): a randomised, double-blind, controlled trial.Lancet. 2020; 396: 1353-1361Summary Full Text Full Text PDF PubMed Scopus (49) Google Scholar showed efficacy of intravenous iron at improving haemoglobin concentration by the time of surgery (mean difference 4·7 g/L, 95% CI 2·7–6·8), and at 8 weeks and 6 months following intervention. The almost identical mean rates of transfusion at 30 days between the two groups (0·65 [SD 1·3] in the placebo group vs 0·61 [1·3] in the iron group) despite no difference in bleeding volumes, suggests a difference in transfusion practice. Although a large number of centres improved the study generalisability, it might also increase heterogeneity. Transfusion rates are known to be highly variable among centres—often dependent on local practice and individual clinician decisions rather than the patients’ clinical state.2Gombotz H Rehak PH Shander A Hofmann A Blood use in elective surgery: the Austrian benchmark study.Transfusion. 2007; 47: 1468-1480Crossref PubMed Scopus (218) Google Scholar For example, if a decision to transfuse is made on the intraoperative rate of blood loss rather than an estimate of red cell mass, then optimising the haemoglobin will not impact the transfusion decision at all. There was no reported standardised transfusion protocol; therefore, any benefit from iron therapy might be obfuscated by the heterogeneity in clinical decision making about the transfusion. Having a uniform approach to transfusion might be the preferred approach to reduce red blood cell use; however, it should not be the only goal of iron therapy. Patient blood management aims to improve (numerous and varied) patient outcomes through the optimisation of red cell mass and minimisation of blood loss.3Spahn DR Moch H Hofmann A Isbister JP Patient blood management: the pragmatic solution for the problems with blood transfusions.Anesthesiology. 2008; 109: 951-953Crossref PubMed Scopus (125) Google Scholar In this sense, the study by Richards and colleagues1Richards T Baikady RR Clevenger B et al.Preoperative intravenous iron to treat anaemia before major abdominal surgery (PREVENTT): a randomised, double-blind, controlled trial.Lancet. 2020; 396: 1353-1361Summary Full Text Full Text PDF PubMed Scopus (49) Google Scholar has shown a benefit. Somewhat surprisingly, increased haemoglobin was not associated with improved postoperative fatigue and there was a significant reduction in readmissions in the first 8 postoperative weeks (risk ratio 0·61, 95% CI 0·40–0·91). Richards and colleagues are right to suggest that much of the benefit shown in the study could be preserved by intrahospital iron therapy; however, without a standardised approach to transfusion, it should not be concluded that improving preoperative red cell mass cannot improve the need for blood transfusion. Further preoperative and postoperative studies noting the haemoglobin and iron status are required. Ideally, adequate time for the intravenous iron to have a therapeutic response should be allowed before surgery, which we understand can be difficult in patients requiring urgent surgery. We declare no competing interests. Preoperative intravenous iron to treat anaemia before major abdominal surgery (PREVENTT): a randomised, double-blind, controlled trialPreoperative intravenous iron was not superior to placebo to reduce need for blood transfusion when administered to patients with anaemia 10–42 days before elective major abdominal surgery. Full-Text PDF Open AccessIron deficiency in PREVENTTToby Richards and colleagues1 suggest that current guidelines on preoperative iron therapy should be reviewed after reporting non-superiority of preoperative intravenous iron over placebo in reducing the need for blood transfusion in adults with anaemia before elective major abdominal surgery. We strongly urge for caution, favouring a more nuanced approach that considers individual circumstances and clinical context when actively managing anaemia before surgery. Similarly to other studies,2,3 we showed benefits of administering preoperative intravenous iron (including a reduced need for subsequent transfusion of red blood cells [RBCs]) to patients with proven iron deficiency anaemia (ferritin <30 μg/L, or where C-reactive protein is elevated >5 mg/L, ferritin <100 μg/L or transferrin saturation of <20%). Full-Text PDF Iron deficiency in PREVENTTToby Richards and colleagues1 found no difference in the need for blood transfusions between the group receiving preoperative intravenous iron versus those receiving placebo. This finding is not surprising and was a consequence of poor study design that disregarded all knowledge on preoperative anaemia treatment, iron metabolism, and ferric carboxymaltose indications and contraindications. Full-Text PDF Iron deficiency in PREVENTT – Authors' replyWe thank Bernd Froessler and colleagues, Axel Hofmann and colleagues, and Anastazia Keegan and colleagues for their comments. In the PREVENTT trial1 we addressed the association between preoperative anaemia and increased blood transfusion, hospital stay, morbidity, and mortality after surgery. We did not know whether these associations were causal, specifically whether intravenous iron could correct anaemia, mediating a reduction in the associated risks to patients. Full-Text PDF