Trends in stroke incidence after hospitalization for atrial fibrillation in Sweden 1987 to 2006

Abstract

Background: To investigate recent trends in incidence of hemorrhagic and non-hemorrhagic strokes in patients with atrial fibrillation (AF). Methods: The Swedish Hospital Discharge and Cause of Death Registries were linked to provide outcome data. Results: 321,276 patients 35 to 84 years (56.5% male, mean age 71.5 years) free of prior stroke with a first AF diagnosis during 1987-2006 were included. Over 3 year follow-up 24,733 patients (7.7%) were diagnosed with ischemic stroke and 2292 (0.7%) with hemorrhagic stroke. The 3-year incidence of ischemic stroke decreased from 8.7% for patients diagnosed in 1987-1991 to 6.6% for those diagnosed in 2002 to 2006. The corresponding incidence of hemorrhagic stroke increased from 0.38% for patients diagnosed in 1987-1991 to 0.57% for those diagnosed in 2002 to 2006. Covariable-adjusted risk of ischemic stroke was significantly reduced (HR 0.65; 0.63-0.68) while risk of hemorrhagic stroke was significantly increased (HR 1.19; 1.05-1.36). Compared to the general population, total stroke risk decreased more among AF patients. Conclusion: We found a considerable decrease in risk of ischemic stroke in Sweden in patients without prior stroke and with a first hospital diagnosis of AF. There was an increased risk of hemorrhagic stroke, but because hemorrhagic stroke represented only a small proportion of all strokes, the overall risk of stroke declined.