Venous thrombosis and breast cancer in older women: Racial differences in risk factors and mortality

Background: Risk factors for venous thromboembolism (VTE) in women with breast cancer are not known by race. Objectives: The purpose of our study was to determine risk factors for VTE and VTE associated mortality in white and black women with breast cancer. Patients and methods: The SEER-Medicare merged database (2000 to 2011) was used for women 65 years and older diagnosed with breast cancer. Stratified by race, logistic regression was used to examine risk factors for VTE and Cox proportional hazards regression was used to evaluate the effect of VTE on mortality. Results: There were 276,028 women 65 years and older with breast cancer. Of those, 6.4% white and 10.1% black women with breast cancer had a diagnosis of VTE. In adjusted analyses by race, risk of VTE increased with each year of age in both white and black cohorts. VTE was independently associated with distant metastasis and coexisting medical conditions in white women and in black women, hypertension, heart failure and hyperlipidemia were determinants of VTE. VTE was not associated with distant metastasis in black women. Tumor size, grade, and receptor status were also not independently associated with VTE risk in either white or black women. VTE accorded a higher risk of death in both white (HR = 1.49, 95% CI, 1.34–1.65) and black women (HR = 1.57, 95% CI, 1.23–2.00) with breast cancer. Conclusion: The study identified VTE risk factors and effect of VTE on mortality in white and black older women with breast cancer.