Comparative rates of adverse events with different formulations of intravenous iron.

Although this is a retrospective analysis of intravenous iron use in a large hospital system, it is the Harvard system and the analysis was carefully done and statistically sound. The study does not include either ferric carboxymaltose or iron isomaltoside as neither are available in the United States. The third of the new compounds, ferumoxytol (the only one of the three new compounds that can be administered as a large doses in a short period of time and is approved in the US) is included but the number of doses is quite small as it was new at the time of data collection.

The study corroborates other intra-institutional analyses and all published prospective studies that show new safety signal differences among the available formulations. Unlike other inferential publications that use spontaneous adverse event reporting (a method that is flawed, specifically proscribed by the FDA, rife with misrepresentative and inaccurate data) this and other direct comparisons support the conclusion that iron sucrose and ferric gluconate offer no advantage in terms of safety, efficacy or ease of administration over low molecular weight iron dextran, the only one of the older formulations that may be administered safely as a total dose infusion. It has been recommended in many publications and by various organizations’ guidelines (e.g. NCCN) that high molecular weight iron dextran be avoided and, appropriately, it was not included in the analysis.

Those of us working in this field are eagerly awaiting comparisons between the newer preparations. It is my opinion, based on very limited observations that they will all be equally effective and safe.

– Michael Auerbach