Abstract 223: National and Regional Trends in Hospitalizations for Hemorrhagic Stroke after Acute Myocardial Infarction in the United States: 1999-2010

Abstract

Background: Elderly survivors of acute myocardial infarction (AMI) are at elevated risk for hemorrhagic stroke, which has a mortality rate of approximately 50%. Increasing use of warfarin for arterial fibrillation and anti-platelet agents for AMI combined with an increasing aging population may have influenced the risk of post-AMI strokes. We sought to characterize temporal trends in the risk for and mortality from hemorrhagic stroke over 12 years among older AMI survivors of different age, sex, race, revascularization status, and region within the US. Methods: We used 100% of Medicare inpatient claims data to identify all fee-for-service (FFS) patients aged> 64 years who were hospitalized for AMI in 1999-2010. We excluded patients who died during the hospitalization or were transferred. Revascularization procedures were identified during the index admission. We used a Cox proportional-hazards regression model to estimate the risk-adjusted annual changes in one-year hemorrhagic stroke hospitalization after AMI, overall and by subgroups. Changes were adjusted by age, gender, race, medical history and comorbidities. We calculated the 30-day mortality among patients readmitted for hemorrhagic stroke. Stroke belt regions were defined as the states with high stroke hospitalization rates in the southeast United States. Results: Among 2,433,036 AMI hospitalizations and 4,852 hemorrhagic stroke readmissions, the risk-adjusted one-year post-AMI hemorrhagic stroke rate remained stable from 1999 to 2010 (range, 0.2% to 0.3%). No significant trends were found for post-AMI stroke rates across all age-sex-race groups and all treatment groups (Figure). Thirty-day mortality rates for stroke after AMI did not show significant changes (1999, 46.7%, 95% CI 39.9%-53.7%; 2010, 50.7%, 95% CI 45.3%-56.1%; range: 46.5% to 54.6%). No difference was found in post-AMI hemorrhagic stroke rates between the stroke belt and non-stroke belt regions. Conclusions: From 1999 to 2010, the overall hospitalization rates of hemorrhagic stroke after AMI were relatively stable without significant changes across all subgroups. Thirty-day mortality rates remained largely unchanged over time. Stroke risk in the stroke belt was not found significantly higher comparing with non-stroke belt states.