Iron Indices in Patients with Functional Anemia in Chronic Kidney Disease

Despite high ferritin level, HDCKD patients may have functional iron deficiency even after intravenous iron (iv) therapy. The aim of this study was to test the hypothesis that lowered serum transferrin level may contribute to functional anemia and erythropoietin hypo responsiveness by the failure to transport accumulated tissue iron to the relevant target tissue.

The study subjects were divided into four groups. Group-A: HDCKD Patients receiving iv iron (n=290). Group-B: Patients not initiated on to hemodialysis (NDCKD), and received oral iron (n=38). Group-C: HDCKD patients with erythropoietin hypo responsiveness (n=9). Group-D: Healthy controls (n=36). The group-A, patients were sub-divided into five groups (A-1 to A-5) based on their serum ferritin levels.

Serum ferritin and tissue iron levels in group-A and C patients were significantly greater than the group-D(p<0.0001) and group-B patients(p<0.001). Transferrin level of group-A and C showed lowered values and consequently a higher %TSAT when compared to group-D. The percent of patients with iron overload was 2.6%, 31%, and 44% in group-B, group-A and group-C respectively. Serum transferrin level significantly correlated with TIBC in group-A and B patients (p<0.0001;p<0.05 respectively). Transferrin level significantly correlated with TIBC in all subgroups of HDCKD(p<0.05) with the exception in subgroup-A2 and with hemoglobin in subgroups A3 (p<0.05) and A5(p<0.01) respectively.

The lowered transferrin level prevents the proper transport of the iron to the hematopoietic sites, which may be a reason for the low hemoglobin synthesis and also for the development of erythropoietin hypo responsiveness in some of the dialysis patients.