title: Thromboembolic risk evaluation in patients with atrial fibrillation using a modified CHADS(2) scoring system.
abstract: BACKGROUND
  Antithrombotic recommendations for relatively low risk patients with atrial fibrillation (AF) are not well established. Some patients with CHADS(2) score = 0 have a CHA(2) DS(2) -VASc score of 2, which indicated warfarin therapy in the latter system. We evaluated the thromboembolic risk in AF patients with a CHADS(2) score of 0 or 1.
  
  
  METHODS
  A total of 695 patients with AF that were followed for ≥ 12 months (median 65.6 months, range 12-138 months), were analyzed retrospectively. The modified CHADS(2) score (MCS) was applied as follows. Each CHADS(2) score group was divided into 2 groups, A and B (i.e., MCS 0A vs 0B, and MCS 1A vs 1B) according to the number of nonmajor risk factors (female gender, chronic kidney disease, coronary artery disease, age 65-74 years). Group A had 0 or 1, and group B had 2 or more nonmajor risk factors.
  
  
  RESULTS
  In patients with CHADS(2) score = 1, there were 13 thromboembolic events (0.65%/year) in 343 MCS 1A patients, and 12 thromboembolic events (1.90%/year) in 108 MCS 1B patients. Thromboembolic risk was significantly higher in the MCS 1B compared to the MCS 1A patients (P = 0.006). In 244 patients with CHADS(2) score = 0, the thromboembolic risk of MCS 0B was similar to that of MCS 0A (P = 0.095), and 26 patients had a CHA(2) DS(2) -VASc score of 2.
  
  
  CONCLUSIONS
  Patients with MCS 1B had a higher thromboembolic risk than patients with MCS 1A. Antithrombotic strategies for patients with a CHA(2) DS(2) -VASc score of 2 but a CHADS(2) score of 0 need further investigation.
authors.affiliation: Department of Internal Medicine, Seoul National University Hospital, Jongno-gu, Seoul, Korea.
authors.forename: Myung-Jin
authors.initials: MJ
authors.lastname: Cha
authors.forename: Gyu-Chul
authors.initials: GC
authors.lastname: Oh
authors.forename: Seokyung
authors.initials: S
authors.lastname: Hahn
authors.forename: Eue-Keun
authors.initials: EK
authors.lastname: Choi
authors.forename: Seil
authors.initials: S
authors.lastname: Oh
mesh_terms: D000368:Aged; D001281:Atrial Fibrillation / Q000175:diagnosis* / Q000453:epidemiology* / Q000503:physiopathology; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008297:Male; D008875:Middle Aged; D012189:Retrospective Studies; D018570:Risk Assessment; D012307:Risk Factors; D012720:Severity of Illness Index; D013923:Thromboembolism / Q000175:diagnosis* / Q000453:epidemiology* / Q000503:physiopathology