Risk of ischemic stroke after atrial fibrillation diagnosis: A national sample cohort

PLoS One. 2017 Jun 21;12(6):e0179687. doi: 10.1371/journal.pone.0179687. eCollection 2017.

Abstract

Atrial fibrillation (AF) is a major risk factor for ischemic stroke and associated with a 5-fold higher risk of stroke. In this retrospective cohort study, the incidence of and risk factors for ischemic stroke in patients with AF were identified. All patients (≥30 years old) without previous stroke who were diagnosed with AF in 2007-2013 were selected from the National Health Insurance Service-National Sample Cohort. To identify factors that influenced ischemic stroke risk, Cox proportional hazard regression analysis was conducted. During a mean follow-up duration of 3.2 years, 1022 (9.6%) patients were diagnosed with ischemic stroke. The overall incidence rate of ischemic stroke was 30.8/1000 person-years. Of all the ischemic stroke that occurred during the follow-up period, 61.0% occurred within 1-year after AF diagnosis. Of the patients with CHA2DS2-VASc score of ≥2, only 13.6% were receiving warfarin therapy within 30 days after AF diagnosis. Relative to no antithrombotic therapy, warfarin treatment for >90 days before the index event (ischemic stroke in stroke patients and death/study end in non-stroke patients) associated with decreased ischemic stroke risk (Hazard Ratio = 0.41, 95%confidence intervals = 0.32-0.53). Heart failure, hypertension, and diabetes mellitus associated with greater ischemic stroke risk. AF patients in Korea had a higher ischemic stroke incidence rate than patients in other countries and ischemic stroke commonly occurred at early phase after AF diagnosis. Long-term (>90 days) continuous warfarin treatment may be beneficial for AF patients. However, warfarin treatment rates were very low. To prevent stroke, programs that actively detect AF and provide anticoagulation therapy are needed.

MeSH terms

  • Adult
  • Aged
  • Aged, 80 and over
  • Anticoagulants / therapeutic use
  • Atrial Fibrillation / complications
  • Atrial Fibrillation / diagnosis*
  • Atrial Fibrillation / drug therapy
  • Diabetes Complications
  • Female
  • Follow-Up Studies
  • Heart Failure / complications
  • Humans
  • Hypertension / complications
  • Incidence
  • Male
  • Middle Aged
  • Multivariate Analysis
  • Proportional Hazards Models
  • Retrospective Studies
  • Risk Factors
  • Stroke / diagnosis*
  • Stroke / epidemiology
  • Stroke / etiology
  • Warfarin / therapeutic use

Substances

  • Anticoagulants
  • Warfarin

Grants and funding

This work was supported by a Korea National Institute of Health Intramural research grant, 4800-4845-302 (2016-NG63003-00).