title: Allopurinol and the risk of atrial fibrillation in the elderly: a study using Medicare data.
abstract: OBJECTIVE
  To assess the effect of allopurinol use on the risk of incident atrial fibrillation (AF) in the elderly.
  
  
  METHODS
  We used the 5% random Medicare Claims data from 2006 to 2012 to examine the association of allopurinol use and incident AF in a cohort of patients with an absence of AF at baseline (at least 365 days). Multivariable-adjusted Cox regression analyses compared allopurinol exposed and non-exposed periods for the risk of AF, controlling for age, sex, race, Charlson-Romano comorbidity index and use of statins, diuretics, ACE inhibitors and β-blockers. HR with 95% CIs was calculated. Sensitivity analyses considered a longer baseline period (365 days vs 183 days) and individual comorbidities.
  
  
  RESULTS
  There were 9244 episodes of incident allopurinol use in 8569 beneficiaries, of which 1366 episodes (14.8%) had incident AF. In multivariable-adjusted analyses, allopurinol use was associated with an HR of 0.83 (95% CI 0.74 to 0.93) for incident AF. In a separate multivariable-adjusted model, compared with no allopurinol use, longer allopurinol use durations were associated with a lower HR of AF: 180 days-2 years, 0.85 (95% CI 0.73 to 0.99) and >2 years, 0.65 (95% CI 0.52 to 0.82). Other factors significantly associated with a higher hazard of AF were: age 75-<85 years and ≥85 years, higher Charlson index score and current β-blocker use. Sensitivity analyses confirmed these findings with minimal/no attenuation of HRs.
  
  
  CONCLUSIONS
  Allopurinol use was associated with a reduced risk of incident AF in the elderly, especially its use for >6 months duration. Future studies should assess the mechanisms underlying this beneficial effect of allopurinol.
authors.affiliation: Medicine Service, Birmingham VA Medical Center, Birmingham, Alabama, USA.|Department of Medicine at School of Medicine, and Division of Epidemiology at School of Public Health, University of Alabama at Birmingham (UAB), Birmingham, Alabama, USA.|Department of Orthopedic Surgery, Mayo Clinic College of Medicine, Rochester, Minnesota, USA.
authors.forename: Jasvinder A
authors.initials: JA
authors.lastname: Singh
authors.affiliation: Department of Medicine at School of Medicine, and Division of Epidemiology at School of Public Health, University of Alabama at Birmingham (UAB), Birmingham, Alabama, USA.
authors.forename: Shaohua
authors.initials: S
authors.lastname: Yu
mesh_terms: D000067575:Administrative Claims, Healthcare / Q000706:statistics & numerical data; D000319:Adrenergic beta-Antagonists / Q000627:therapeutic use; D000367:Age Factors; D000368:Aged; D000369:Aged, 80 and over; D000493:Allopurinol / Q000627:therapeutic use*; D001281:Atrial Fibrillation / Q000453:epidemiology*; D015897:Comorbidity; D005260:Female; D006074:Gout Suppressants / Q000627:therapeutic use*; D006801:Humans; D015994:Incidence; D008297:Male; D006278:Medicare / Q000706:statistics & numerical data*; D012189:Retrospective Studies; D018570:Risk Assessment; D012307:Risk Factors; D014481:United States / Q000453:epidemiology
chemical_list: D000319:Adrenergic beta-Antagonists; D006074:Gout Suppressants; D000493:Allopurinol
keywords: Cardiovascular Disease; Epidemiology; Health services research