P280 The clinical significance of hypophosphataemia after intravenous iron infusions for iron deficiency anaemia

Introduction Intravenous (IV) iron is commonly used to treat iron deficiency in patients with severe anaemia or intolerance to oral iron supplements. Ferric carboxymaltose (FCM) is an IV iron known to cause a fall in serum phosphate in up to 70% of patients. Although several isolated patient cases with severe hypophosphataemia-related symptoms post-FCM administration have been published, the clinical significance of this side effect has not been studied in a wider population. The purpose of this retrospective study was to examine the clinical relevance of IV iron-induced hypophosphataemia in a UK population to inform clinical practice and implement service improvements. Methods The medical notes of 321 randomly selected patients, who received an FCM infusion at UCLH during the audit period (April 2016-December 2018), were retrospectively examined. After excluding patients without a post-FCM phosphate measurement, the records of 209 patients, who received 224 courses of FCM, were analysed. Of those patients, 162 received FCM as inpatients and 47 as outpatients. A treatment course consisted of one or two infusions depending on the patient’s iron need. If the time interval between two infusions was >4 weeks, each infusion was analysed as a separate course. Data were separated into two groups depending on whether or not hypophosphataemia (defined as phosphate Results The overall incidence of hypophosphataemia increased from 3.4% at baseline to 27.7% post-FCM. Among the courses reporting hypophosphataemia, 8.1% showed severe hypophosphataemia (defined as phosphate A statistically significant drop in the mean phosphate level occurred post-FCM administration. The drop was more substantial in patients with hypophosphataemia post-FCM, where the phosphate level was reduced by ~50% (p Conclusions The incidence of hypophosphataemia following FCM administration was high. Hypophosphataemia was persistent. The incidence of hypophosphataemia at 60 days post-FCM was 40%.Treatment was necessary in 24% of courses reporting hypophosphataemia; an average of 4.4 phosphate infusions were administered per patient. This impacts on the patient and on the utilisation of healthcare resources.