Evaluation of serum iron as a predictor of a hemoglobin response to injectable iron treatment in chronic hemodialysis patients

Background. - The detection and correction of iron deficiency are essential for the treatment of anemia in chronic hemodialysis patients. The aim of our study was to assess the ability of serum iron to predict hemoglobin response to intravenous iron supplementation in hemodialysis patients.Methods. - It is a retrospective study in 91 hemodialysis patients during 2016 at Clermont-Ferrand University Hospital for whom intravenous iron supplementation had been started. A responder patient was defined as an increase in hemoglobin greater than or equal to 1 g/dL/month and/or a decrease in the dose of erythropoiesis stimulating agent after two months of iron supplementation. Results. - In responding patients, serum iron was significantly lower (6.7 +/- 2.7 mu mol/L) compared to non-responding patients (8.9 +/- 2.9 mu mol/L; P < 0.001). The positive response to iron supplementation was significantly associated with low serum iron (odds ratio = 0.58 [0.42-0.81]; P = 0.002) in a logistic regression model taking into account ferritin, transferrin saturation coefficient, dose variation monthly iron and erythropoiesis stimulating agent and the duration of dialysis. The area under the receiver operating characteristic curve of serum iron, ferritin and transferrin saturation coefficient to predict the response to iron supplementation were 0.72, 0.51 and 0.64, respectively (serum iron versus ferritin [P = 0.006] and serum iron versus transferrin saturation coefficient [P = 0.04]). The sensitivity for serum iron below 7.5 mu mol/L was better than that for ferritin below 86 ng/mL (P < 0.001) and the specificity for serum iron below 7.5 mu mol/L was better than that for TSC less than 19% (P = 0.02). Conclusion. - Serum iron below 7.5 mu mol/L can predict the success of the response to iron supplementation in chronic hemodialysis patients.