Effect of Intravenous Ferric Carboxymaltose Treatment on Serum Phosphorus Levels in Non-Dialysis Patients with Chronic Kidney Disease: A Retrospective Observational Study

ABSTRACTObjective: Anemia is common in chronic kidney disease (CKD), particularly when the glomerular filtration rate (GFR) falls below 30 mL/min/1.73m2. Iron deficiency exacerbates anemia, and intravenous ferric carboxymaltose (FCM) is frequently used due to its rapid iron delivery and low risk of hypersensitivity. However, FCM has been linked to hypophosphatemia, with limited data in non-dialysis CKD patients. This study evaluated the occurrence of hypophosphatemia and changes in serum phosphorus after FCM therapy in this population.Methods: We retrospectively analyzed 113 adult non-dialysis CKD patients (stages 3A–5) who received intravenous FCM for iron deficiency anemia between 2022 and 2023. Patients had baseline and 1-month serum phosphorus and creatinine measurements; those with dialysis, acute infection, malignancy, active inflammation, phosphate binder use, or documented malnutrition were excluded. Phosphorus changes were compared across CKD stages, and factors associated with hypophosphatemia (