Incidence of Hypophosphatemia after Ferric Carboxymaltose Treatment: Single Center Experience

Abstract

Aim: The aim of this study was to evaluate the incidence of hypophosphatemia after ferric carboxymaltose (FCM) infusion and the factors affectinghypophosphatemia.Materials and Methods: Ninety-two patients who received FCM treatment for iron deficiency anemia (IDA) were included in the study. Phosphorus,calcium, magnesium, 25-hydroxy vitamin D, and parathyroid hormone levels before and after FCM infusion were obtained from the medical records.Hypophosphatemia was defined as serum phosphorus level of <2.5 mg/dL and severe hypophosphatemia as <1 mg/dL. The cut-off value for baselinephosphorus in predicting hypophosphatemia was detected as 3.4 mg/mL with the ROC analysis.Results: Seventy-seven of the patients were women. The mean age was 47.5±15.5 (18-85) years. Thirty of the patients (32.6%) were given 500mg iron as FCM and 62 patients (67.4%) were given 1000 mg iron as FCM. The level of serum phosphorus measured 10-14 days after FCM wasdetermined lower than the baseline level (2.22±0.57 mg/dL vs 3.34±0.39 mg/dL, p<0.000). Hypophosphatemia was observed in 62 patients (67.4%)after FCM infusion. Severe hypophosphatemia was seen in only 2 patients (2.1%). Patients given a dose of 1000 mg FCM had a higher incidenceof hypophosphatemia compared to those given 500 mg FCM (75.8% vs 50%, p=0.013). Baseline phosphorus level of 3.4 mg/dL was associatedwith an increased risk of developing hypophosphatemia with an odds ratio of 9.2 (p=0.001; 95% confidence interval: 3.41-25.21). On logisticregression analysis, it was found that baseline phosphorus level and a dose of 1000 mg FCM were independent risk factors for the development ofhypophosphatemia.Conclusion: The incidence of hypophosphatemia due to FCM in our study was consistent with the literature. When FCM treatment is given topatients with IDA, the patients should be evaluated according to their baseline phosphorus level, the dose of FCM and frequency of administration,and it should be kept in mind to follow the phosphorus level in patients with risk for hypophosphatemia.