SUN-752 Exploring an Underrated Aspect of Intravenous Ferric Carboxymaltose Therapy: Real World Data Exploring Hypophosphataemia and The Need for Monitoring

Abstract Disclosure: R. Singh: None. K. Finch: None. M. Kumar: None. Background: Ferric carboxymaltose (FCM - Ferrinject, Vifor Pharma) is widely used in clinical practice to treat iron deficiency anemia (IDA) due to its efficacy, convenience and increasing evidence in heart failure and CKD. However, its association with hypophosphatemia can impact on patients' quality of life. There are no current guidelines on monitoring for hypophosphatemia following FCM. Objective: Real-world study investigating the frequency of hypophosphatemia following FCM administration. Method: This single center retrospective cohort study investigated the prevalence of hypophosphatemia amongst inpatients receiving FCM. All patients prescribed FCM were identified from the hospital’s electronic prescribing system for a 12-month period (August 2022-23), then stratified by age, sex, ethnicity and indication for FCM. Data was collected from the admission case notes. The primary objective was to determine the incidence, severity and treatment of hypophosphatemia following FCM. Results: 1074 patients were identified as having FCM, 388 had incidental pre-injection phosphate levels recorded and 145 had corresponding post-injection levels (notably none for monitoring for hypophosphatemia), forming the study cohort. The study participants were predominantly white British (98%) and older (median 81yrs (IQR 72-87yrs)) with 61% female and 39% male. The participants were sampled from medicine 81%, orthopedics 15%, day care unit (PIU) 3%, surgery <1%. Pre and post-FCM mean phosphate levels were, 1.03 mmol/L and 0.88mmol/L, respectively. Post-FCM hypophosphatemia was observed in 34% (50 patients). Of these, 48 received treatment for hypophosphatemia, 36 with oral phosphate replacement (Phosphate Sandoz effervescent tablets) and 12 receiving intravenous replacements (500ml Phosphate Polyfusor, with 25% requiring 2 infusions) following clinical assessment of severity. For patients treated with IV phosphate, the mean pre-FCM phosphate level was 0.80 mmol/L, dropping to a mean of 0.39 mmol/L post-injection. Among patients who developed hypophosphatemia, 87.7% were treated with FCM for iron deficiency anemia (IDA), 1.8 % heart failure, 7% acute bleeding, and 3.5% had IDA with underlying immune thrombocytopenia (ITP). Conclusion: This study has shown a significant lack of routine monitoring for hypophosphatemia in patients receiving FCM. 34% of patients receiving FCM were found to have incidental hypophosphatemia, of these 96% were treated with phosphate replacement and a 25% of these deemed to need intravenous phosphate replacement. It is very likely a significant proportion of patients with this complication are missed. We recommend a protocol for monitoring for this complication post FCM. Presentation: Sunday, July 13, 2025