Kamaraju S, et al. - In this surveillance, epidemiology, and end results (SEER)-Medicare-based population study involving 5,648 older women (age ≥ 67 years) treated for breast cancer from June 30, 2006, to June 1, 2008, researchers compared cardiovascular events between women treated with aromatase inhibitors (AIs; n=4,690) and women treated with tamoxifen (n=958), with a presumption that AIs increase the risk of myocardial infarction (MI). The participants were followed through December 31, 2012. The investigators developed and assigned stabilized probability of treatment weights and used the Fine and Gray model for time to MI with death not associated with MI as a competing risk. According to findings, MI occurred in 251 patients, and 22 patients died of MI during the study period, while 476 died of other causes. After adjusting for the known MI risk factors at the start of adjuvant therapy (diabetes, ischemic heart disease, congestive heart failure, MI, and peripheral vascular disease), no significantly different hazard for MI was observed between AI vs tamoxifen groups.