Association of Cardiovascular Risk Factors With Cardiac Events and Survival Outcomes Among Patients With Breast Cancer Enrolled in SWOG Clinical Trials

BackgroundCardiovascular disease is the primary cause of death among patients with breast cancer. However, the association of cardiovascular-disease risk factors (CVD-RFs) with long-term survival and cardiac events is not well studied.MethodsWe examined SWOG (formerly the Southwest Oncology Group) breast cancer trials from 1999 to 2011. We identified baseline diabetes, hypertension, hypercholesterolemia, and coronary artery disease by linking trial records to Medicare claims. The primary outcome was overall survival. Patients with both baseline and follow-up claims were examined for cardiac events. Cox regression was used to assess the association between CVD-RFs and outcomes.ResultsWe identified 1,460 participants older than 66 years of age from five trials; 842 were eligible for survival outcomes analysis. At baseline, median age was 70 years, and median follow-up was 6 years. Hypertension (73%) and hypercholesterolemia (57%) were the most prevalent conditions; 87% of patients had one or more CVD-RF. Th...