Objective: To compare utilization and associated costs of epoetin alfa (EPO) and darbepoetin alfa (DARB), two erythropoiesis-stimulating agents (ESAs), in patients with cancer undergoing chemotherapy and patients with chronic kidney disease (CKD) not on dialysis in inpatient and outpatient hospital settings.
Methods: An analysis of medical claims recorded between January 2006 and December 2009 was conducted using the Premier Perspective Comparative Hospital database. Patients included were ≥18 years old with cancer and chemotherapy or with pre-dialysis CKD and with ≥1 claim for EPO or DARB during a hospital inpatient or outpatient treatment episode. Patients treated with both ESAs or who were receiving dialysis were excluded. Mean cumulative drug costs and dose ratios (units EPO: mcg DARB) were calculated using cumulative dose and April 2010 wholesale acquisition costs.
Results: Cancer chemotherapy: 13,832 inpatient stays (EPO: 10,454; DARB: 3378) and 5590 outpatient treatment episodes (EPO: 2856; DARB: 2734) were identified. The inpatient and outpatient populations reported ESA dose ratios of 230:1 and 238:1 with DARB cost premiums of 42% (EPO: $948; DARB: $1348) and 38% (EPO: $3358; DARB: $4627), respectively. CKD: 148,746 hospital stays (EPO: 116,017; DARB: 32,729) and 11,012 outpatient treatment episodes (EPO: 6921; DARB 4091) were identified. The inpatient and outpatient populations reported ESA dose ratios of 251:1 and 257:1 with DARB cost premiums of 30% (EPO: $566; DARB: $738) and 27% (EPO: $2077; DARB: $2642), respectively.
Limitations: The lack of randomization may have led to confounding by indication. In addition, statistical significance must be interpreted with caution in studies involving large samples.
Conclusions: This study of 19,422 patients with cancer receiving chemotherapy and 159,758 patients with pre-dialysis CKD reported ESA dose ratios ranging from 230:1-257:1 (units EPO: mcg DARB) and associated cost premiums of 27-42% for DARB.