title: Benefit of anticoagulation unlikely in patients with atrial fibrillation and a CHA2DS2-VASc score of 1.
abstract: BACKGROUND
  Patients with atrial fibrillation (AF) and ≥1 point on the stroke risk scheme CHA2DS2-VASc (congestive heart failure, hypertension, age ≥75 years, diabetes mellitus, stroke/transient ischemic attack, vascular disease, age 65-74 years, sex category) are considered at increased risk for future stroke, but the risk associated with a score of 1 differs markedly between studies.
  
  
  OBJECTIVE
  The goal of this study was to assess AF-related stroke risk among patients with a score of 1 on the CHA2DS2-VASc.
  
  
  METHODS
  We conducted this retrospective study of 140,420 patients with AF in Swedish nationwide health registries on the basis of varying definitions of "stroke events."
  
  
  RESULTS
  Using a wide "stroke" diagnosis (including hospital discharge diagnoses of ischemic stroke as well as unspecified stroke, transient ischemic attack, and pulmonary embolism) yielded a 44% higher annual risk than if only ischemic strokes were counted. Including stroke events in conjunction with the index hospitalization for AF doubled the long-term risk beyond the first 4 weeks. For women, annual stroke rates varied between 0.1% and 0.2% depending on which event definition was used; for men, the corresponding rates were 0.5% and 0.7%.
  
  
  CONCLUSIONS
  The risk of ischemic stroke in patients with AF and a CHA2DS2-VASc score of 1 seems to be lower than previously reported.
authors.affiliation: Karolinska Institute, Department of Clinical Sciences at Danderyd Hospital and Department of Cardiology at Danderyd Hospital, Stockholm, Sweden. Electronic address: leif.friberg@ki.se.
authors.forename: Leif
authors.initials: L
authors.lastname: Friberg
authors.affiliation: Karolinska Institute, Department of Clinical Sciences at Danderyd Hospital and Department of Cardiology at Danderyd Hospital, Stockholm, Sweden.
authors.forename: Mika
authors.initials: M
authors.lastname: Skeppholm
authors.affiliation: Department of Medical Sciences, Uppsala University Hospital, Uppsala, Sweden.
authors.forename: Andreas
authors.initials: A
authors.lastname: Terént
mesh_terms: D000368:Aged; D000925:Anticoagulants / Q000627:therapeutic use; D001281:Atrial Fibrillation / Q000188:drug therapy / Q000453:epidemiology*; D002545:Brain Ischemia / Q000453:epidemiology* / Q000517:prevention & control; D005260:Female; D006801:Humans; D008297:Male; D012042:Registries; D012189:Retrospective Studies; D018570:Risk Assessment; D020521:Stroke / Q000453:epidemiology* / Q000517:prevention & control; D013548:Sweden / Q000453:epidemiology; D014859:Warfarin / Q000627:therapeutic use
chemical_list: D000925:Anticoagulants; D014859:Warfarin
keywords: epidemiology; oral anticoagulation; stroke