title: CHADS2 score and risk of new-onset atrial fibrillation: a nationwide cohort study in Taiwan.
abstract: BACKGROUND
  The components of CHADS2 score were reported to be important risk factors for the development of atrial fibrillation (AF). The goal of the current study was to investigate whether the CHADS2 score was a useful scheme in predicting new-onset AF. Furthermore, we aimed to use the CHADS2 scoring system to estimate the individual risk in developing AF for patients with different comorbidities.
  
  
  METHODS
  From January 1, 2000 to December 31, 2001, a total of 702,502 patients older than 18 years old and who had no history of cardiac arrhythmias were identified from the "National Health Insurance Research Database" released by the Taiwan National Health Research Institutes. The CHADS2 score was calculated for every patient. Finally, 628,807 (score 0), 47,039 (score 1), 15,655 (score 2), 6843 (score 3), 3315 (score 4), 790 (score 5) and 53 (score 6) patients were studied and followed for the occurrences of AF.
  
  
  RESULTS
  During a follow-up of 9.0 ± 2.2 years, there were 9187 (1.3%) patients experiencing new-onset AF. The incidence of AF was 1.5 per 1000 patient-years. The incidence increased from 0.8 per 1000 patient-years for patients with a CHADS2 score of 0 to 34.6 per 1000 patient-years for those with a CHADS2 score of 6. After an adjustment for the gender and comorbidities, the hazard ratio (95% confidence interval) of each increment of the CHADS2 score in predicting AF was 2.342 (2.309-2.375; p<0.001).
  
  
  CONCLUSIONS
  The CHADS2 score, consisting of an age >75 and several clinical risk factors was useful in risk estimation and stratification of new-onset AF.
authors.affiliation: Division of Cardiology, Department of Medicine, Taipei Veterans General Hospital, Taipei, Taiwan; Institute of Clinical Medicine, and Cardiovascular Research Center, National Yang-Ming University, Taipei, Taiwan.
authors.forename: Tze-Fan
authors.initials: TF
authors.lastname: Chao
authors.forename: Chia-Jen
authors.initials: CJ
authors.lastname: Liu
authors.forename: Su-Jung
authors.initials: SJ
authors.lastname: Chen
authors.forename: Kang-Ling
authors.initials: KL
authors.lastname: Wang
authors.forename: Yenn-Jiang
authors.initials: YJ
authors.lastname: Lin
authors.forename: Shih-Lin
authors.initials: SL
authors.lastname: Chang
authors.forename: Li-Wei
authors.initials: LW
authors.lastname: Lo
authors.forename: Yu-Feng
authors.initials: YF
authors.lastname: Hu
authors.forename: Ta-Chuan
authors.initials: TC
authors.lastname: Tuan
authors.forename: Tsu-Juey
authors.initials: TJ
authors.lastname: Wu
authors.forename: Tzeng-Ji
authors.initials: TJ
authors.lastname: Chen
authors.forename: Shih-Ann
authors.initials: SA
authors.lastname: Chen
mesh_terms: D000328:Adult; D001281:Atrial Fibrillation / Q000175:diagnosis* / Q000453:epidemiology*; D015331:Cohort Studies; D016208:Databases, Factual; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008297:Male; D008875:Middle Aged; D012042:Registries; D012307:Risk Factors; D012720:Severity of Illness Index; D013624:Taiwan / Q000453:epidemiology
keywords: Atrial fibrillation; CHADS(2) score; Incidence