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Comment on "The Important Role for Intravenous Iron in Perioperative Patient Blood Management in Major Abdominal Surgery: A Randomized Controlled Trial".

To the Editor: I t is with interest that we read the article by Froessler et al reporting a randomized controlled study of the use of parenteral iron to correct preoperative anemia and reduce perioperative blood transfusion in patients undergoing major abdominal surgery. The authors conclude that the use of parenteral iron preoperatively in those patients deemed to be anemic due to iron deficiency was of significant benefit, in particular, that it was associated with reduced perioperative blood transfusion, higher preoperative hemoglobin concentration, and reduced length of stay. This was consistent with prior meta-analysis reporting similar results with the use of intravenous iron preparations. Clearly, as they state, a reduction in the requirement for perioperative allogeneic blood transfusion is desirable for a number of reasons, including the relative scarcity of it as a healthcare resource, concerns with transmission of blood borne infection, other adverse effect such as transfusion reaction, an association with increased postoperative complications, and the underlying concern that blood transfusion has the potential to increase the risk of disease recurrence after cancer surgery. However, recruitment into their study was based on the measurement of iron stores using ferritin, transferrin saturation, and hemoglobin levels. This is potentially problematical since many patients undergoing major abdominal surgery do so for cancer and have evidence of a systemic inflammatory response (eg, C-reactive protein >10 mg/L as measured in their study). The systemic inflammatory response is known to perturb these measurements such that there is an apparent iron deficiency. Moreover, the presence of a preoperative systemic inflammatory response is recognized to predict poor outcomes in patients undergoing cancer surgery. Therefore, the systemic inflammatory response is potentially an important confounder with clear implications for the preoperative treatment of iron deficiency and the interpretation of study results. It is clear from the C-reactive protein measurements that a proportion of the patients in the study by Froessler et al had evidence of systemic inflammation before surgery and given the above, iron deficiency was apparent rather than real in these patients and as a consequence some patients may not have benefited from an iron infusion. Indeed, it may be speculated that the benefit of the iron infusion was confined to those patients who did not have evidence of systemic inflammation. We encourage the authors to report such analysis and other workers considering the use of iron infusion, to correct anemia, to monitor the systemic inflammatory response in the pre and postoperative period.