title: The prevalence of atrial fibrillation in a geographically well-defined population in northern Sweden: implications for anticoagulation prophylaxis.
abstract: OBJECTIVE
  The aims of this study were to evaluate the community-based prevalence of atrial fibrillation (AF) in a western society using a geographically well-defined population in the northern part of Sweden as a reference and to estimate the proportion of patients eligible for oral anticoagulation (OAC) prophylactic therapy according to the stroke risk indices CHADS2 and CHA2 DS2 -VASc. Bleeding risk was assessed using the HAS-BLED score.
  
  
  METHODS
  The study population was recruited from AURICULA, a Swedish national quality register for patients receiving anticoagulation treatment. All patients with the diagnosis AF in the catchment area are registered in AURICULA.
  
  
  RESULTS
  Of the 65 532 inhabitants in the catchment area, 1616 were diagnosed with AF (1200 cases were characterized as chronic AF). Thus, the overall prevalence of AF was 2.5%. The prevalence increased with age from 6.3% in patients over 55 years of age to 13.8% in those over 80 years. The prevalence was higher in men than in women in all age groups. Overall, 56.3% and 85.1% of the population were at high risk of stroke (≥2 points) according to CHADS2 and CHA2 DS2 -VASc, respectively. In addition, 26.9% had an increased bleeding risk according to HAS-BLED.
  
  
  CONCLUSIONS
  Within this large Caucasian population, we identified the highest community-based prevalence of AF to date. The prevalence was strongly associated with increasing age and male gender. Using CHA2 DS2 -VASc instead of CHADS(2) widened the indication for OAC prophylactic therapy of AF in this population.
authors.affiliation: Department of Internal Medicine, Hudiksvall Hospital, Hudiksvall, Sweden. per.andersson@lg.se
authors.forename: P
authors.initials: P
authors.lastname: Andersson
authors.forename: M
authors.initials: M
authors.lastname: Löndahl
authors.forename: N-J
authors.initials: NJ
authors.lastname: Abdon
authors.forename: A
authors.initials: A
authors.lastname: Terent
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000925:Anticoagulants / Q000008:administration & dosage / Q000009:adverse effects; D001281:Atrial Fibrillation / Q000150:complications / Q000175:diagnosis / Q000188:drug therapy / Q000453:epidemiology; D003695:Delivery of Health Care; D016903:Drug Monitoring / Q000379:methods; D015716:Electrocardiography, Ambulatory; D005260:Female; D006301:Health Services Needs and Demand; D006470:Hemorrhage / Q000139:chemically induced / Q000517:prevention & control; D006801:Humans; D008297:Male; D008875:Middle Aged; D015995:Prevalence; D018570:Risk Assessment; D012307:Risk Factors; D055502:Secondary Prevention; D020521:Stroke / Q000209:etiology / Q000517:prevention & control; D013548:Sweden / Q000453:epidemiology; D014859:Warfarin / Q000008:administration & dosage / Q000009:adverse effects
chemical_list: D000925:Anticoagulants; D014859:Warfarin