Clinical significance of a novel reticulocyte-based erythropoietin resistance index in HD patients: A retrospective study.

INTRODUCTION: The erythropoietin resistance index (ERI) is an indicator of erythropoiesis-stimulating agent (ESA) responsiveness and is typically calculated using Hb. However, Hb does not directly reflect ESA-induced erythropoiesis because of its long-term nature. We thus designed a novel ERI calculated with reticulocyte Hb (RetHb), a real-time index, and investigated its association with mortality in HD patients. METHODS: We calculated the ERI using the change in RetHb before and after ESA administration (ERIΔRetHb ) and retrospectively analyzed its association with 3-year all-cause mortality using Kaplan-Meier survival curves and Cox regression analyses. RESULTS: A total of 102 patients were included. Patients with the highest ERIΔRetHb had the worst prognosis according to the Kaplan-Meier survival curves (Log-rank p = 0.02). Multivariate Cox regression analysis showed that the ERIΔRetHb was significantly and independently associated with all-cause mortality (hazard ratio: 9.82, 95% CI [1.50, 64.41], p = 0.02). CONCLUSION: The ERIΔRetHb was significantly and independently associated with all-cause mortality in HD patients.

Acceleration of iron utilization after intravenous iron administration during activated erythropoiesis in hemodialysis patients: a randomized study.

This study aimed to evaluate the effect of different timings of iron administration during erythropoiesis activated by continuous erythropoietin receptor activator (CERA) on reticulocyte iron uptake in hemodialysis patients. In total, 110 patients were randomized to receive 40 mg intravenous elemental iron doses at all three hemodialysis sessions in the first week (IW1 group: n = 57) or in the third week (IW3 group: n = 53) after CERA administration. Following CERA administration at day 0, reticulocyte count increased, peaking at day 7. At days 7 and 14, the observed changes in Ret-He were higher in the IW1 group than in the IW3 group. Increases in total reticulocyte hemoglobin at day 7 were higher in the IW1 group than in the IW3 group. In contrast, there was only tendency toward greater total reticulocyte hemoglobin after iron administration in the third week in the IW3 group. Intravenous iron supplementation in the first week of CERA administration increases reticulocyte iron uptake; however, iron supplementation in the third week does not. The findings indicate that iron should be intravenously administered to increase the efficacy of CERA within 1 week of CERA administration during highly active erythropoiesis.

Changes in hepcidin and reticulocyte hemoglobin equivalent levels in response to continuous erythropoietin receptor activator administration in hemodialysis patients: a randomized study.

Inadequate iron availability limits the response to erythropoiesis-stimulating agents (ESA) and hepcidin is a key regulator of iron metabolism. However, there is little information concerning time-dependent changes in hepcidin in response to the change of accelerated iron demand due to ESA-induced erythropoiesis. In this study, iron-related parameters, including hepcidin levels, were explored in comparison to patients receiving continuous erythropoietin receptor activator (CERA) and epoetin beta (EPO) treatment. Ninety-four patients were randomized to receive monthly CERA (N = 47) or EPO three times/week (N = 47). After the titration period, hemoglobin levels and iron-related parameters were examined. Data for 71 patients were evaluated (CERA, N = 34; EPO, N = 37). Compared with EPO treatment, CERA treatment caused significant decreases within 1 week in hepcidin (-93.5 ± 46.9 vs. -1.3 ± 38.3 ng/mL, P < 0.01), reticulocyte hemoglobin equivalent (Ret-He) (-4.03 ± 2.64 vs. -1.13 ± 1.41 pg, P < 0.01), ferritin (-58.9 ± 30.5 vs. -12.2 ± 23.8 ng/mL, P < 0.01) and transferrin saturation (-13.2 ± 9.1 vs. 1.0 ± 11.9%, P < 0.01) and significant increases within 2 weeks in the levels of hemoglobin (0.42 ± 0.38 vs. -0.02 ± 0.48 g/dL, P < 0.01). In conclusion, hepcidin, Ret-He, ferritin and transferrin saturation levels decreased within 1 week and hemoglobin increased within 2 weeks after CERA administration. Time course of iron-related parameters including hepcidin demonstrated accelerated iron utilization appropriately according to ESA-induced erythropoiesis.