Risk and predictors of stroke after myocardial infarction among the elderly: results from the Cooperative Cardiovascular Project

Abstract

Background: Stroke is an important outcome after acute myocardial infarction. Studies that have examined this relationship have largely excluded older patients, even though half of stroke admissions occur among patients 75 years of age and older.

Methods and results: Among 111 023 medicare patients discharged with a principal diagnosis of acute myocardial infarction during an 8-month period in 1994 to 1995, we identified hospital admissions for ischemic stroke within 6 months of discharge. The rate of admission was 2.5% within 6 months. Independent predictors of ischemic stroke were age greater-than-or-equal 75 years, black race, no aspirin at discharge, frailty, prior stroke, atrial fibrillation, diabetes, hypertension, and history of peripheral vascular disease. To identify individuals at increased risk for stroke, a risk stratification score was constructed from identified factors. The 6-month stroke admission rate for patients with a score of 4 or higher (approximately 20% of the total sample) was approximately 4%.

Conclusions: The risk of stroke after myocardial infarction is substantial, with about 1 in 40 patients suffering an ischemic stroke within 6 months of discharge. Simple clinical factors can predict the risk of stroke and, based on these factors, we identified 20% of older patients who have a 1 in 25 chance of being hospitalized for a stroke within 6 months of discharge.