title: Clinical Benefit of American College of Chest Physicians versus European Society of Cardiology Guidelines for Stroke Prophylaxis in Atrial Fibrillation.
abstract: BACKGROUND
  Guidelines for anticoagulant therapy in patients with atrial fibrillation (AF) conflict with each other. The American College of Chest Physicians (ACCP) guidelines suggest no anticoagulant therapy for patients with a CHADS2 score of 0. The European Society of Cardiology (ESC) prefer anticoagulant therapy for patients with a CHA2DS2-VASc of 1, which includes 65-74-year-olds with a CHADS2 score of 0. Resolving this conflicting advice is important, because these guidelines have potential to change anticoagulant therapy in 10 % of the AF population.
  
  
  METHODS
  Using the National Registry of Atrial Fibrillation (NRAF) II data set, we compared these guidelines using stroke equivalents. Based on structured review of 23,657 patient records, we identified 65-74-year-old patients with a CHADS2 stroke score of 0 and no contraindication to warfarin. We used Medicare claims data to ascertain rates of ischemic stroke, intracranial hemorrhage, and other hemorrhage. We calculated net stroke equivalents for these (N = 478) patients using a weight of 1.5 for intracranial hemorrhages (ICH) and 1.0 for ischemic stroke. In a multivariate analysis, we used 14,466 records with documented atrial fibrillation and adjusted for CHADS2 and HEMORR2 HAGES score.
  
  
  RESULTS
  In 65-74-year-old patients with a CHADS2 stroke score of 0, the stroke equivalents per 100 patient-years was 2.6 with warfarin and 2.9 without warfarin; the difference between these two strategies was not significant (0.3 stroke equivalents, 95 % CI -3.2 to 3.7). However, rates of hemorrhage per 100 patient-years were nearly tripled (hazard ratio 2.9; 95 % CI 1.5-5.4; p = 0.0011) with warfarin (21.1) versus without it (7.4). The most common site for major hemorrhage was gastrointestinal (ICD-9 code 578.9).
  
  
  CONCLUSIONS
  By expanding warfarin use to 65--74-year-olds with a CHADS2 score of 0, rates of hemorrhages would rise without a significant reduction in stroke equivalents.
authors: Washington University in St. Louis Medical School Campus, Box 8005, 660 S. Euclid Ave., St. Louis, MO, USA.
authors: Ambar A
authors: AA
authors: Andrade
authors: Juan
authors: J
authors: Li
authors: Martha J
authors: MJ
authors: Radford
authors: David S
authors: DS
authors: Nilasena
authors: Brian F
authors: BF
authors: Gage
mesh_terms: D000368:Aged; D000925:Anticoagulants / Q000627:therapeutic use; D001281:Atrial Fibrillation / Q000188:drug therapy*; D005060:Europe; D005260:Female; D006470:Hemorrhage / Q000453:epidemiology; D006801:Humans; D008297:Male; D017410:Practice Guidelines as Topic / Q000592:standards*; D012042:Registries; D012307:Risk Factors; D012955:Societies, Medical / Q000592:standards*; D020521:Stroke / Q000517:prevention & control*; D014481:United States; D014859:Warfarin / Q000627:therapeutic use
chemical_list: D000925:Anticoagulants; D014859:Warfarin