title: Secondary Prevention of Stroke with Warfarin in Patients with Nonvalvular Atrial Fibrillation: Subanalysis of the J-RHYTHM Registry.
abstract: BACKGROUND
  Prior ischemic stroke or transient ischemic attack (TIA) is a high risk for thromboembolism in patients with nonvalvular atrial fibrillation (NVAF). To clarify rates of thromboembolic and hemorrhagic events, and target intensities of warfarin for secondary prevention, a subanalysis was performed using data from the J-RHYTHM Registry.
  
  
  METHODS
  Of 7937 outpatients with atrial fibrillation, 7406 with NVAF (men 70.8%, 69.8 ± 10.0 years) were followed for 2 years or until an event occurred. Event rates and effect of warfarin were compared between patients with (secondary prevention) and without (primary prevention) prior stroke/TIA.
  
  
  RESULTS
  Prevalence of male sex, diabetes mellitus, and mean age were higher in the secondary prevention group, showing a higher CHADS2 (congestive heart failure, hypertension, age 75 years or older, diabetes mellitus, and history of stroke or TIA) score than the primary prevention group (3.5 ± 1.0 versus 1.4 ± 1.0, P < .001). In the secondary prevention group, 93.4% of patients received warfarin and their time in therapeutic range was 62.8%. During follow-up, thromboembolism occurred more frequently in the secondary than in the primary prevention group (2.8% versus 1.5%, P = .004), especially in patients without warfarin. Major hemorrhage also occurred more frequently in the secondary prevention group (3.0% versus 1.7%, P = .006). Compared with patients not taking warfarin, combined rates of both events were lower at an international normalized ratio (INR) of 1.6-2.59 in patients taking warfarin in the secondary as well as in the primary prevention groups.
  
  
  CONCLUSIONS
  Both thromboembolism and major hemorrhage occurred more frequently in NVAF patients with prior ischemic stroke/TIA. Target INR should be 1.6-2.59 for secondary as well as primary prevention of thromboembolism in Japanese NVAF patients.
authors.affiliation: Department of Internal Medicine and Cardiology, Nippon Medical School, Tama-Nagayama Hospital, Tokyo, Japan. Electronic address: kodani@nms.ac.jp.
authors.forename: Eitaro
authors.initials: E
authors.lastname: Kodani
authors.affiliation: Department of Internal Medicine and Cardiology, Nippon Medical School, Tama-Nagayama Hospital, Tokyo, Japan.
authors.forename: Hirotsugu
authors.initials: H
authors.lastname: Atarashi
authors.affiliation: Second Department of Internal Medicine, Graduate School of Medicine, University of Toyama, Toyama, Japan.
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Inoue
authors.affiliation: Department of Cardiology, Respiratory Medicine and Nephrology, Hirosaki University Graduate School of Medicine, Aomori, Japan.
authors.forename: Ken
authors.initials: K
authors.lastname: Okumura
authors.affiliation: The Cardiovascular Institute, Tokyo, Japan.
authors.forename: Takeshi
authors.initials: T
authors.lastname: Yamashita
authors.affiliation: Division of Biostatistics and Clinical Epidemiology, University of Toyama, Toyama, Japan.
authors.forename: Hideki
authors.initials: H
authors.lastname: Origasa
mesh_terms: D000367:Age Factors; D000368:Aged; D000369:Aged, 80 and over; D000925:Anticoagulants / Q000627:therapeutic use*; D001281:Atrial Fibrillation / Q000150:complications* / Q000188:drug therapy / Q000453:epidemiology / Q000401:mortality; D015331:Cohort Studies; D005260:Female; D005343:Fibrinolytic Agents / Q000627:therapeutic use; D006801:Humans; D008297:Male; D008875:Middle Aged; D011237:Predictive Value of Tests; D015995:Prevalence; D012042:Registries; D012307:Risk Factors; D055502:Secondary Prevention; D020521:Stroke / Q000453:epidemiology / Q000209:etiology* / Q000401:mortality / Q000517:prevention & control*; D014859:Warfarin / Q000627:therapeutic use*
chemical_list: D000925:Anticoagulants; D005343:Fibrinolytic Agents; D014859:Warfarin
keywords: Atrial fibrillation; anticoagulation; secondary prevention; stroke; warfarin