Abstract 64: The Use of Oral Anticoagulation After Ischemic Stroke Increases, Users Have Fewer Recurrences, and Are Increasingly Likely to Survive. A Nationwide Study From Finland

Abstract

Background and Purpose: Oral anticoagulation (OAC) is an effective secondary preventive therapy after atrial fibrillation related cardioembolic ischemic stroke. We explored the use of OAC after ischemic stroke in Finland, the country with the most rapidly aging population in Europe. Methods: Data from 1999 to 2010 were extracted from the PERFECT Stroke registry, a nationwide database of all incident stroke patients hospitalized in Finland. Purchase of warfarin, the only OAC available during the study period in Finland, was registered in all pharmacies in a national database. Recurrence was defined as re-hospitalization with new acute stroke diagnosis through an emergency department. Survival was tracked from the national death registry with 100% follow-up. Results: Among the 99,677 incident ischemic stroke cases over the study period, there were 24,327 cases surviving their initial hospitalization and using OAC for secondary prevention. This represented 24.4% of all ischemic stroke patients, increasing from 20.3% in 1999 to 26.7% in 2010. In these OAC users, 1-year recurrence rate of ischemic stroke decreased from 20.1% in 1999 to 12.5% in 2010, while 1-year hemorrhagic stroke rate remained unchanged at 0.4%. Increases in the secondary preventive use of blood pressure medications (from 83.5% to 92.7%), statins (from 32.8% to 73.5%), and a combination of these (from 28.2% to 69.0%) were observed from 1999 to 2010. One-year case-fatality of patients surviving to go home was 4.2% when no recurrences occurred. When secondary prevention failed, patients who experienced a new ischemic stroke had 11.3% likelihood of dying within a year, increasing to 42.0% after a hemorrhagic stroke. After adjusting for age, sex, and comorbidities with a logistic regression model, the odds of 1-year case-fatality decreased over time (OR 0.97; 95% CI 0.95-0.99 per year). Conclusion: As the population ages, the proportion of ischemic stroke patients that require oral anticoagulation increases, in our data from 20% to 27% over a period of 12 years. Secondary prevention of stroke in OAC users improved, which could be due to increased use of antihypertensives and statins, and reflected on survival. The risk of hemorrhagic stroke due to anticoagulation for ischemic stroke remains small.