Background: Epoetin alfa (EPO) and darbepoetin alfa (DARB) are erythropoietic agents indicated in the United States for the treatment of anemia in chronic kidney disease (CKD).
Objective: This study investigated dosing patterns and costs associated with the use of erythropoietic-stimulating therapy (EST) in patients with CKD not on dialysis who were newly starting EPO or DARB therapy in managed care organizations.
Methods: This was a retrospective analysis of medical claims data from >30 health plans for the period from July 2002 to February 2005. Patients were included if they were aged > or =18 years, had > or =1 claim for CKD within 90 days before the initiation of treatment, had newly started therapy with EPO or DARB, and had received > or =2 doses of treatment. If a patient was undergoing renal dialysis, data were censored 30 days before the first date of dialysis. Patients with a diagnosis of cancer or who had undergone chemotherapy were excluded from the analysis. The mean dosing interval was determined for both groups. Mean weekly doses and costs (using 2005 wholesale acquisition costs), weighted by the treatment duration, were calculated. The frequency of outpatient nephrologist visits was described and included in cost considerations.
Results: The study population consisted of 595 patients who received EPO and 260 who received DARB. The EPO group was significantly older than the DARB group (mean age, 63.5 vs 61.2 years, respectively; P = 0.020). The proportion of women was similar between the 2 groups (51.6% and 50.4%). Use of extended dosing (> or =q2wk) was common in both groups (63.2% and 90.8%). The weighted mean weekly dose was 11,536 U for EPO and 42.5 mug for DARB. The mean number of outpatient nephrologist visits during treatment was similar between the 2 groups (3.9 and 3.5). Mean weekly costs (EST drug cost plus cost of nephrologist visits) were significantly lower for EPO compared with DARB (159 dollars vs 205 dollars; P < 0.001).
Conclusions: The majority of these CKD patients newly started on EST in managed care organizations received extended dosing regimens (> or =q2wk) of EPO or DARB. EPO treatment was associated with significantly lower mean weekly costs compared with DARB. The number of outpatient nephrology visits did not differ significantly between groups.