ESAs associated with increased risk for VTE but not mortality

Although the number of patients receiving erythropoiesis-stimulating agents increased 10-fold from 1991 to 2002, an analysis of more than 50,000 patients showed that blood transfusion rates did not change. Results also demonstrated an increased risk for venous thromboembolism among patients receiving erythropoiesis-stimulating agents.

Researchers selected 56,210 patients aged 65 years or older diagnosed with breast, colon or non–small cell lung cancers or diffuse large B-cell lymphoma during that 11-year period. A total of 15,346 patients (27%) received ESAs. The proportion of patients who received those agents increased from 4.8% in 1991 to 45.9% by 2002. The blood transfusion rate remained steady at 22% per year.

From diagnosis to the end of follow-up, 11% of 47,342 patients were newly diagnosed with venous thromboembolism. Among patients who received ESAs, 14.3% experienced venous thromboembolism compared with only 9.8% of patients who did not received ESAs. Patients with five or more claims for ESAs were more likely to experience venous thromboembolism (HR=1.55; 95% CI, 1.44-1.66) than those with fewer claims (HR=1.31; 95% CI, 1.19-1.44).

“When we stratified the analyses by year of diagnosis and limited patient follow-up to four years, we found that for each time period, ESA use was associated with at least a twofold increase in venous thromboembolism events,” the researchers wrote.

They went on to say that although survival free of venous thromboembolism was shorter for patients who received ESAs, there was no association between ESA use and increased risk for death.

Hershman DL. J Natl Cancer Inst. 2009;doi:10.1093/jnci/djp387.