title: Risk factors for stroke and thromboembolism in relation to age among patients with atrial fibrillation: the Loire Valley Atrial Fibrillation Project.
abstract: BACKGROUND
  According to the latest European guidelines on the management of nonvalvular atrial fibrillation (NVAF), all patients aged ≥ 65 years should be treated with oral anticoagulation (if not contraindicated). Therefore, stroke risk factors should be investigated exclusively in patients with NVAF aged < 65 years.
  
  
  METHODS
  Patients diagnosed with NVAF in a four-hospital institution between 2000 and 2010 were identified. Event rates of stroke/thromboembolism were calculated according to age category (ie, age < 65, 65-74, and ≥ 75 years). Independent risk factors of stroke and thromboembolism were investigated in univariate and multivariate Cox regression models including patients with NVAF aged < 65 years only. The effect of adding vascular disease to the CHADS(2) (congestive heart failure, hypertension, age ≥ 75 years, diabetes, previous stroke) score was examined by net reclassification improvement (NRI) and integrated discrimination improvement (IDI) models.
  
  
  RESULTS
  Among 6,438 patients with NVAF, 2,002 (31.1%) were aged < 65 years. In patients with no CHADS(2) risk factors who were not treated with anticoagulation (n = 1,035), the stroke/thromboembolic event rate per 100 person-years was 0.23 (95% CI, 0.08-0.72), 2.05 (95% CI, 1.07-3.93), and 3.99 (95% CI, 2.63-6.06) in those aged < 65, 65-74, and ≥ 75 years, respectively. Heart failure, previous stroke, and vascular disease were significantly associated with increased risk of stroke/thromboembolism in both univariate and multivariate analyses, and vascular disease significantly improved the predictive ability of the CHADS(2) score (NRI, 0.40; IDI, 0.031).
  
  
  CONCLUSIONS
  Patients with NVAF aged ≥ 65 years have event rates that merit oral anticoagulation. In patients with NVAF aged < 65 years, the risk of stroke/thromboembolism is independently increased by the presence of heart failure, previous stroke, or vascular disease. As proposed in the new CHA(2)DS(2)-VASc (congestive heart failure, hypertension, age ≥ 75 years, diabetes, previous stroke, vascular disease, age 65-74 years, sex category [female]) score, stroke risk stratification by the CHADS(2) score can be improved by the addition of age 65 to 74 years and vascular disease.
authors.affiliation: University of Birmingham Centre for Cardiovascular Sciences, City Hospital, Birmingham, England; Department of Cardiology, Copenhagen University Hospital Gentofte, Hellerup, Denmark.
authors.forename: Jonas Bjerring
authors.initials: JB
authors.lastname: Olesen
authors.affiliation: Service de Cardiologie, Pôle Coeur Thorax Vasculaire, Centre Hospitalier Universitaire Trousseau et Faculté de Médecine, Université François Rabelais, Tours, France. Electronic address: lfau@med.univ-tours.fr.
authors.forename: Laurent
authors.initials: L
authors.lastname: Fauchier
authors.affiliation: University of Birmingham Centre for Cardiovascular Sciences, City Hospital, Birmingham, England.
authors.forename: Deirdre A
authors.initials: DA
authors.lastname: Lane
authors.affiliation: Service de Cardiologie, Pôle Coeur Thorax Vasculaire, Centre Hospitalier Universitaire Trousseau et Faculté de Médecine, Université François Rabelais, Tours, France.
authors.forename: Sophie
authors.initials: S
authors.lastname: Taillandier
authors.affiliation: University of Birmingham Centre for Cardiovascular Sciences, City Hospital, Birmingham, England.
authors.forename: Gregory Y H
authors.initials: GYH
authors.lastname: Lip
mesh_terms: D000367:Age Factors; D000368:Aged; D000925:Anticoagulants / Q000627:therapeutic use; D001281:Atrial Fibrillation / Q000150:complications* / Q000453:epidemiology; D002423:Cause of Death / Q000639:trends; D005260:Female; D005500:Follow-Up Studies; D005602:France / Q000453:epidemiology; D006760:Hospitalization / Q000639:trends; D006801:Humans; D015994:Incidence; D008297:Male; D008875:Middle Aged; D016016:Proportional Hazards Models; D012189:Retrospective Studies; D018570:Risk Assessment / Q000379:methods*; D012307:Risk Factors; D020521:Stroke / Q000453:epidemiology* / Q000209:etiology / Q000517:prevention & control; D015996:Survival Rate / Q000639:trends; D013923:Thromboembolism / Q000453:epidemiology* / Q000209:etiology / Q000517:prevention & control
chemical_list: D000925:Anticoagulants