Conversion from Epoetin Alfa to Darbepoetin Alfa: Effects on Patients’ Hemoglobin and Costs to Canadian Dialysis Centres

Abstract

The erythropoiesis-stimulating agents epoetin alfa (EPO) and darbepoetin alfa (DPO) effectively treat the anemia that occurs in most patients undergoing hemodialysis. Published studies indicate that these 2 agents have similar efficacy and safety outcomes, but their relative costs in actual practice in Canada have not been extensively studied. To determine the relative utilization and cost of erythropoiesis-stimulating agents in Canadian practice. Secondary objectives were to examine various clinical parameters in patients receiving these drugs. In this retrospective, open-label, observational study, 3 hospital-based hemodialysis centres in Ontario, Canada, converted patients from EPO to DPO over the period July 2004 to April 2006. The starting dose-conversion ratio was 200:1. The dose of DPO was changed, as needed, to achieve the same target hemoglobin (Hb) as before the conversion (110-120 g/L). For 3 to 6 months before conversion, and for 6 to 12 months after, weekly dose of erythropoiesis-stimulating agent, dose-conversion ratio, serum Hb, ferritin, and transferrin saturation were recorded for each patient at all 3 sites. One site also documented medication administration errors before and after the conversion. Data were collected for a total of 442 patients. Baseline patient characteristics were similar across the 3 sites. The median dose-conversion ratio for each hemodialysis centre ranged from 288:1 to 400:1, and the average annual per-patient savings varied between $2140 and $4711. No clinically meaningful differences between EPO and DPO were reported in terms of patients' serum hemoglobin levels, iron dose, or number of transfusions. With DPO, the relative risk of medication administration errors was reduced by 72% (p < 0.001) (based on data from one site). In this real-world evaluation of the clinical effectiveness and cost-efficiency of switching patients from EPO to DPO, patients' clinical outcomes were maintained while considerable reductions in cost were achieved.