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

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.