Comparison of red blood cell transfusion rates of epoetin alfa and darbepoetin alfa in an inpatient oncology setting

Abstract

16002 Background: Epoetin alfa (EPO) and darbepoetin alfa (DARB) are used to treat cancer-related anemia and to reduce the requirements for blood transfusions. To date, limited information on the relative effectiveness of these agents in the inpatient setting is available. This analysis evaluated red blood cell (RBC) transfusion rates in cancer patients receiving EPO or DARB during hospitalization. Methods: An analysis of electronic inpatient hospital records from the Premier Perspective Comparative Hospital Database was conducted to compare RBC transfusion rates in cancer patients receiving EPO or DARB therapy. Study subjects were identified through hospitalizations recorded between 07/2002 and 03/2005 from over 500 hospitals nationwide. Patients were required to be ≥18 years old, have a primary admitting diagnosis of cancer and be treated with EPO or DARB during hospitalization. Patients who had received renal dialysis were excluded. To minimize effects of outliers, 5% of patients with extreme doses in each group were excluded from the dosing analysis. In addition to descriptive statistics on transfusion requirements, a multivariate logistic model was employed to isolate the effect of an individual erythropoietic agent on the risk of RBC transfusion after controlling for patient demographics, comorbidities, admission characteristics, use of IV or oral iron and hospitalization severity markers. Results: Among the 24,814 EPO and 2,990 DARB study patients, mean age and gender distribution at admission were similar (age: EPO 65.3 years, DARB 64.5 years; %women: EPO 53%, DARB 55%). Mean cumulative dose per inpatient stay was EPO 61,656 ± 50,274 Units and DARB 259 ± 340 mcg. RBC transfusions occurred in 37.9% of EPO patients compared to 39.8% of DARB patients (p=0.0404). Transfused EPO patients received a mean of 2.24 units versus 2.20 units for DARB patients (p=0.2111). After adjusting for covariates, the multivariate model confirmed that DARB treatment was associated with a higher risk of transfusion compared to EPO (odds ratio: 1.2, 95% CI: 1.1–1.3, p=0.0007). Conclusions: This analysis of inpatients with cancer indicates DARB treatment is associated with a higher risk of receiving RBC transfusion compared to treatment with EPO. [Table: see text]