Erythropoiesis-Stimulating Agents for Chemotherapy Induced Anemia: Analysis of an Electronic Medical Record Database within a Large Oncology/Hematology Practice.

BACKGROUND: Erythropoiesis-stimulating agents (ESAs) are commonly administered as supportive care for anemia in patients receiving chemotherapy. While comparative analyses of these agents using claims data are available, electronic medical records offer a new data source for such analyses, one which may provide greater clinical detail. This retrospective, observational study using electronic medical record data was conducted to gain a better understanding of real-world treatment patterns and clinical outcomes in patients with cancer receiving chemotherapy and ESA therapy.

METHODS: Electronic medical record data from a large oncology/hematology practice in the southeastern United States was collected from January 1, 2005 to September 30, 2006. Inclusion criteria consisted of patients receiving ≥ 2 doses of either epoetin alfa (EPO) or darbepoetin alfa (DARB) with concurrent chemotherapy and a cancer diagnosis 30 days prior to or during the ESA treatment episode. An ESA treatment episode was defined as continuous treatment with EPO or DARB and without EPO or DARB administration 35 days prior to the first or after the last administration. Patients were excluded if they had a diagnosis of myelodysplastic syndrome or switched ESA medications during an episode. Baseline characteristics, cancer type, chemotherapy utilization, ESA dosing, and response to ESA therapy were measured during the most recent complete ESA treatment episode. Response to therapy was defined as attainment of Hb ≥11.0 g/dL at any point during the treatment episode from an initial Hb of <11.0 g/dL. A binomial logistic regression model was developed to assess the percent of responders in the EPO and DARB cohort.

RESULTS: A total of 1,211 patients were included in the EPO group; 62.5% women, mean age 62.0 ± 13.1, and mean starting Hb level 10.8 ± 1.0 g/dL. In the DARB group, there were 419 patients; 68.5% women, mean age 60.0 ± 13.5, and mean starting Hb 10.9 ± 1.0 g/dL. The proportion of patients with lung cancer was significantly higher in the EPO cohort (EPO 24.4% vs DARB 15.8%, p=0.0003) while the proportion of patients with breast cancer was significantly higher in the DARB cohort (EPO 31.5% vs DARB 39.6%, p=0.0023). All other cancer types were similar between the groups. A greater proportion of EPO patients received platinum-based chemotherapy compared to those receiving DARB (EPO 37.3% vs DARB 26.5%, p<0.0001). The majority of patients in both cohorts received every 2 week dosing (9.1–18.0 days) (EPO 55.8% vs DARB 60.4%, p=NS). After controlling for gender, age, initial Hb level, cancer diagnosis, and use of platinum-based chemotherapy, patients with an initial Hb < 11.0 g/dL were 1.77 times more likely to attain Hb ≥ 11.0 g/dL in the EPO-treated group vs the DARB-treated group (p=0.0031).

DISCUSSION: These results indicate that EMR data can provide detailed information on usage patterns within a practice. In this clinic, differences were seen in the type of patient receiving either EPO or DARB, while more than half of patients with chemotherapy-induced anemia received their ESA treatment every 2 weeks, regardless of agent. Additionally, more patients with an initial Hb of <11.0 g/dL responded to treatment when treated with EPO compared to DARB.