National trends in stroke after acute myocardial infarction among Medicare patients in the United States: 1999 to 2010

Abstract

Stroke is a common and important adverse event after acute myocardial infarction (AMI) in the elderly. It is unclear whether the risk of stroke after AMI has changed with improvements in treatments and outcomes for AMI in the last decade. To assess trends in risk of stroke after AMI, we used a national sample of Medicare data to identify Fee-for-Service patients (n = 2,305,441) aged ≥65 years who were discharged alive after hospitalization for AMI from 1999 to 2010. We identified 57,848 subsequent hospitalizations for ischemic stroke and 4,412 hospitalizations for hemorrhagic stroke within 1 year after AMI. The 1-year rate of ischemic stroke decreased from 3.4% (95% CI 3.3%-3.4%) to 2.6% (2.5%-2.7%; P < .001). The risk-adjusted annual decline was 3% (hazard ratio, 0.97; [0.97-0.98]) and was similar across all age and sex-race groups. The rate of hemorrhagic stroke remained stable at 0.2% and did not differ by subgroups. The 30-day mortality for patients admitted with ischemic stroke after AMI decreased from 19.9% (18.8%-20.9%) to 18.3% (17.1%-19.6%) and from 48.3% (43.0%-53.6%) to 45.7% (40.3%-51.2%) for those admitted with hemorrhagic stroke. We observed a decrease in 1-year mortality from 37.8% (36.5%-39.1%) to 35.3% (33.8%-36.8%) for ischemic stroke and from 66.6% (61.4%-71.5%) to 60.6% (55.1%-65.9%) for hemorrhagic stroke. From 1999 to 2010, the 1-year risk for ischemic stroke after AMI declined, whereas the risk of hemorrhagic stroke remained unchanged. However, 30-day and 1-year mortality continued to be high.