title: Target international normalized ratio values for preventing thromboembolic and hemorrhagic events in Japanese patients with non-valvular atrial fibrillation: results of the J-RHYTHM Registry.
abstract: BACKGROUND
  Target anticoagulation levels for warfarin in Japanese patients with non-valvular atrial fibrillation (NVAF) are unclear.
  
  
  RESULTS
  Of 7,527 patients with NVAF, 1,002 did not receive warfarin (non-warfarin group), and the remaining patients receiving warfarin were divided into 5 groups based on their baseline international normalized ratio (INR) of prothrombin time (≤1.59, 1.6-1.99, 2.0-2.59, 2.6-2.99, and ≥3.0). Patients were followed-up prospectively for 2 years. Primary endpoints were thromboembolic events (cerebral infarction, transient ischemic attack, and systemic embolism), and major hemorrhage requiring hospital admission. During the follow-up period, thromboembolic events occurred in 3.0% of non-warfarin group, but at lower frequencies in the warfarin groups (2.0, 1.3, 1.5, 0.6, and 1.8%/2 years for INR values of ≤1.59, 1.6-1.99, 2.0-2.59, 2.6-2.99, and ≥3.0, respectively; P=0.0059). Major hemorrhage occurred more frequently in warfarin groups (1.5, 1.8, 2.4, 3.3, and 4.1% for INR values ≤1.59, 1.6-1.99, 2.0-2.59, 2.6-2.99, and ≥3.0, respectively; P=0.0041) than in non-warfarin group (0.8%/2 years). These trends were maintained when the analyses were confined to patients aged ≥70 years.
  
  
  CONCLUSIONS
  An INR of 1.6-2.6 is safe and effective at preventing thromboembolic events in patients with NVAF, particularly patients aged ≥70 years. An INR of 2.6-2.99 is also effective, but associated with a slightly increased risk in major hemorrhage. (UMIN Clinical Trials Registry UMIN000001569)
authors.affiliation: Second Department of Internal Medicine, Toyama University Hospital.
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Inoue
authors.forename: Ken
authors.initials: K
authors.lastname: Okumura
authors.forename: Hirotsugu
authors.initials: H
authors.lastname: Atarashi
authors.forename: Takeshi
authors.initials: T
authors.lastname: Yamashita
authors.forename: Hideki
authors.initials: H
authors.lastname: Origasa
authors.forename: Naoko
authors.initials: N
authors.lastname: Kumagai
authors.forename: Masayuki
authors.initials: M
authors.lastname: Sakurai
authors.forename: Yuichiro
authors.initials: Y
authors.lastname: Kawamura
authors.forename: Isao
authors.initials: I
authors.lastname: Kubota
authors.forename: Kazuo
authors.initials: K
authors.lastname: Matsumoto
authors.forename: Yoshiaki
authors.initials: Y
authors.lastname: Kaneko
authors.forename: Satoshi
authors.initials: S
authors.lastname: Ogawa
authors.forename: Yoshifusa
authors.initials: Y
authors.lastname: Aizawa
authors.forename: Masaomi
authors.initials: M
authors.lastname: Chinushi
authors.forename: Itsuo
authors.initials: I
authors.lastname: Kodama
authors.forename: Eiichi
authors.initials: E
authors.lastname: Watanabe
authors.forename: Yukihiro
authors.initials: Y
authors.lastname: Koretsune
authors.forename: Yuji
authors.initials: Y
authors.lastname: Okuyama
authors.forename: Akihiko
authors.initials: A
authors.lastname: Shimizu
authors.forename: Osamu
authors.initials: O
authors.lastname: Igawa
authors.forename: Shigenobu
authors.initials: S
authors.lastname: Bando
authors.forename: Masahiko
authors.initials: M
authors.lastname: Fukatani
authors.forename: Tetsunori
authors.initials: T
authors.lastname: Saikawa
authors.forename: Akiko
authors.initials: A
authors.lastname: Chishaki
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D000925:Anticoagulants / Q000008:administration & dosage / Q000009:adverse effects; D044466:Asian People; D001281:Atrial Fibrillation / Q000188:drug therapy / Q000453:epidemiology; D005260:Female; D005500:Follow-Up Studies; D006470:Hemorrhage / Q000139:chemically induced / Q000453:epidemiology; D006801:Humans; D019934:International Normalized Ratio; D007564:Japan / Q000453:epidemiology; D008297:Male; D008875:Middle Aged; D013923:Thromboembolism / Q000453:epidemiology / Q000209:etiology / Q000517:prevention & control; D014859:Warfarin / Q000008:administration & dosage / Q000009:adverse effects
chemical_list: D000925:Anticoagulants; D014859:Warfarin