Hormone therapy and the risk of stroke after acute myocardial infarction in postmenopausal women

OBJECTIVES We examined the association of hormone therapy (HRT) with hemorrhagic and ischemic stroke among postmenopausal women with acute myocardial infarction (AMI). BACKGROUND Hemorrhagic and ischemic strokes are common complications of AMI, and women are at increased risk for hemorrhagic stroke after thrombolytic therapy. This risk may be related to female hormones. METHODS Using data from the National Registry of Myocardial Infarction-3, we studied 114,724 women age 55 years or older admitted to the hospital for AMI, of whom 7,353 reported HRT use on admission. We determined rates of in-hospital hemorrhagic and ischemic stroke stratified by HRT use and estimated the independent association of HRT with each stroke type using multivariable logistic regression. RESULTS The HRT users were younger than non-users, had fewer risk factors for stroke including diabetes and prior stroke, and received more pharmacologic and invasive therapy including cardiac catheterization. A total of 2,152 (1.9%) in-hospital strokes occurred, with 442 (0.4%) hemorrhagic, 1,017 (0.9%) ischemic and 693 (0.6%) unspecified. Among HRT users and non-users, the rates of hemorrhagic stroke (0.40% vs. 0.42%, P = 1.00) and ischemic stroke (0.80% vs. 0.96%, P = 0.11) were similar. Among 13,328 women who received thrombolytic therapy, the rate of hemorrhagic stroke was not significantly different for users and non-users (1.6% vs. 2.1%, P = 0.22). After adjustment for baseline and treatment differences, HRT was not associated with hemorrhagic (odds ratio [OR], 0.88; 95% confidence intervals [CI], 0.58 to 1.35) or ischemic stroke (OR, 0.89; CI, 0.66 to 1.18). CONCLUSIONS Acute myocardial infarction is a high-risk setting for stroke among postmenopausal women, but HRT does not appear to modify that risk. Clinicians should not alter their approach to thrombolytic therapy based on HRT use.