Comparison of Pain and Efficacy of Darbepoetin Alfa and Epoetin Beta Pegol Treatment in Patients Receiving Peritoneal Dialysis

Background: Sustained erythropoiesis-stimulating agents (ESAs) have recently been identified as the standard therapeutic agent for anemia in patients undergoing peritoneal dialysis (PD). However, few reports have compared pain between various types of sustained ESAs or between administration routes. Furthermore, the change ratio of the dose of sustained ESAs reportedly ranges from 0.8 to 1.3. In the present study, to compare darbepoetin alfa and epoetin beta pegol (a continuous erythropoietin receptor activator [CERA]), we examined the dolorific differences between administration routes and the effect on anemia by using a chjange ratio of 0.8 with darbepoetin alfa in patients with renal anemia undergoing PD. Subjects and Method: We randomly assigned 20 patients with stable hemoglobin levels undergoing PD to either a darbepoetin alfa therapy group or a CERA therapy group. Based on a previous report, the change ratio of the CERA group from CERA to darbepoetin alfa therapy was assumed to be 0.8, and therapy was crossed-over to darbepoetin alfa again 2 months later. The dolorific evaluation (pain measurement) used both a face scale and a visual analogue scale. We compared the agents as well as administration routes with respect to pain. We also measured variables related to anemia and iron metabolism. Results: The change ratio of the CERA group at the start of the study was 0.821. On resumption of darbepoetin alfa therapy 2 months later, the doses of darbepoetin alfa increased. The darbepoetin alfa group showed a stronger tendency for pain, although the difference was not significant. In contrast, subcutaneous administration in the CERA group showed significant pain just after injection. The CERA group, however, showed a significant decrease in hemoglobin levels after 2 months of treatment (p= 0.0489). No significant change was found in the hematocrit or the reticulocyte count. There were no significant differences in iron metabolism, as shown by serum iron levels and total iron-binding capacity, in either group. However, serum ferritin levels showed a tendency to decrease in the darbepoetin alfa group. Conclusion: No significant difference in pain was found between darbepoetin alfa and CERA therapies, but a significant difference in pain was noted between administration routes, just after injection, in the CERA group. The results also suggest that a change ratio of 0.8 from darbepoetin alfa to CERA is low for managing anemia. (J Nippon Med Sch 2015; 82: 21―26)