title: The risk of atrial fibrillation in patients with rheumatoid arthritis.
abstract: BACKGROUND
  Prior research suggests an important role of systemic inflammation in pathogenesis of atrial fibrillation (AF). It is well known that rheumatoid arthritis (RA), a chronic, systemic inflammatory disorder, increases the risk of cardiovascular disease (CVD), but little evidence exists whether the risk of AF is increased in RA.
  
  
  METHODS
  Using data from a large US commercial insurance plan, we examined the incidence rate (IR) of hospitalisation for AF in patients with RA compared with non-RA. RA patients were identified with ≥2 separate visits coded for RA and ≥1 disease-modifying antirheumatic drug dispensing. The IR of AF in RA patients was also compared with those with osteoarthritis, a chronic non-inflammatory condition.
  
  
  RESULTS
  There were 20 852 RA and 104 260 non-RA patients, matched on age, sex and index date. The mean follow-up was 2 years. The IR per 1000 person-years of AF was 4.0 (95% CI 3.4 to 4.7) in RA and 2.8 (95% CI 2.6 to 3.0) in non-RA patients. The IR ratio for AF was 1.4 (95% CI 1.2 to 1.7) in RA compared with non-RA patients. In a multivariable Cox model adjusting for a number of risk factors such as diabetes, CVD, medications and healthcare utilisation, the risk of AF was no longer increased in RA (HR 1.1, 95% CI 0.9 to 1.4) compared with non-RA patients. There was also no difference in the AF risk between RA and osteoarthritis patients.
  
  
  CONCLUSIONS
  Our results show no increased risk of AF associated with RA, after adjusting for various comorbidities, medications and healthcare use.
authors.affiliation: Division of Pharmacoepidemiology and Pharmacoeconomics, Brigham and Women's Hospital, , Boston, Massachusetts, USA.
authors.forename: Seoyoung C
authors.initials: SC
authors.lastname: Kim
authors.forename: Jun
authors.initials: J
authors.lastname: Liu
authors.forename: Daniel H
authors.initials: DH
authors.lastname: Solomon
mesh_terms: D000328:Adult; D001172:Arthritis, Rheumatoid / Q000150:complications / Q000453:epidemiology* / Q000276:immunology; D001281:Atrial Fibrillation / Q000453:epidemiology* / Q000209:etiology / Q000276:immunology; D002318:Cardiovascular Diseases / Q000453:epidemiology; D015897:Comorbidity; D003920:Diabetes Mellitus / Q000453:epidemiology; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D015999:Multivariate Analysis; D010003:Osteoarthritis / Q000453:epidemiology / Q000276:immunology; D016016:Proportional Hazards Models; D012307:Risk Factors; D014481:United States / Q000453:epidemiology
keywords: Cardiovascular Disease; Inflammation; Rheumatoid Arthritis