title: Comparison of management patterns and clinical outcomes in patients with atrial fibrillation in Canada and the United States (from the analysis of the Atrial Fibrillation Follow-up Investigation of Rhythm Management [AFFIRM] database).
abstract: Little is known about differences in practice patterns or outcomes in the management of patients who have atrial fibrillation in Canada compared with those in the United States (US). We evaluated the effect that the country of enrollment may have on the management patterns and clinical outcomes in patients who participated in the AFFIRM study. Three thousand four hundred patients came from the US and 660 from Canada. In the US, patients were more likely to have a history of coronary artery disease (39% vs 35%, p = 0.03), hypertension (72% vs 67%, p = 0.01), or congestive heart failure (24% vs 18%, p = 0.0002). More US participants were <65 years of age (25% vs 19%, p = 0.003). Although at randomization the use of warfarin was comparable, during follow-up Canadians were more likely to be treated with warfarin and to be therapeutically anticoagulated. Mortality rate at 5 years was higher in US patients (24% vs 16%, p = 0.001), and the composite end point (death, disabling stroke, major bleeding, cardiac arrest, or anoxic encephalopathy) was also higher in US patients (30% vs 22%, p = 0.0005). Even after adjusting for known differences in baseline characteristics, the risk of death was lower in Canada (hazard ratio 0.70, p = 0.02). In conclusion, in the AFFIRM study, US subjects were more likely to have preexisting cardiovascular diseases despite being younger (<65 years old) than those in Canada. Effective warfarin therapy was more commonly employed in Canada. After correcting for the known differences in baseline characteristics, Canadian patients who had atrial fibrillation had a lower mortality risk.
authors.affiliation: Institut de Cardiologie, Hôpital Laval, Quebec, Quebec, Canada. gilles.ohara@med.ulaval.ca
authors.forename: Gilles E
authors.initials: GE
authors.lastname: O'Hara
authors.forename: Lyne
authors.initials: L
authors.lastname: Charbonneau
authors.forename: Mary
authors.initials: M
authors.lastname: Chandler
authors.forename: Humberto J
authors.initials: HJ
authors.lastname: Vidaillet
authors.forename: François
authors.initials: F
authors.lastname: Philippon
authors.forename: Magdi
authors.initials: M
authors.lastname: Sami
authors.forename: Thomas A
authors.initials: TA
authors.lastname: Rocco
authors.forename: Farooq A
authors.initials: FA
authors.lastname: Padder
authors.forename: Jean
authors.initials: J
authors.lastname: Champagne
authors.forename: Craig M
authors.initials: CM
authors.lastname: Pratt
authors.forename: Benoit
authors.initials: B
authors.lastname: Coutu
authors.forename: D George
authors.initials: DG
authors.lastname: Wyse
mesh_terms: D000368:Aged; D000889:Anti-Arrhythmia Agents / Q000627:therapeutic use*; D000925:Anticoagulants / Q000627:therapeutic use*; D001281:Atrial Fibrillation / Q000188:drug therapy* / Q000401:mortality*; D002170:Canada / Q000453:epidemiology; D005260:Female; D005500:Follow-Up Studies; D006339:Heart Rate / Q000187:drug effects; D006801:Humans; D008297:Male; D008875:Middle Aged; D010818:Practice Patterns, Physicians'; D016896:Treatment Outcome; D014481:United States / Q000453:epidemiology; D014859:Warfarin / Q000627:therapeutic use
chemical_list: D000889:Anti-Arrhythmia Agents; D000925:Anticoagulants; D014859:Warfarin