title: Atrial fibrillation patients do not benefit from acetylsalicylic acid.
abstract: OBJECTIVE
  Oral anticoagulation is the recommended treatment for stroke prevention in patients with atrial fibrillation. Notwithstanding, many patients are treated with acetylsalicylic acid (ASA) as monotherapy. Our objective was to investigate if atrial fibrillation patients benefit from ASA as monotherapy for stroke prevention.
  
  
  RESULTS
  Retrospective study of patients with a clinical diagnosis of atrial fibrillation between 1 July 2005 and 1 January 2009 in the National Swedish Patient register, matched with data from the National Prescribed Drugs register. Endpoints were ischaemic stroke, thrombo-embolic event, intracranial haemorrhage, and major bleeding. The study population consisted of 115 185 patients with atrial fibrillation, of whom 58 671 were treated with ASA as monotherapy and 56 514 were without any antithrombotic treatment at baseline. Mean follow-up was 1.5 years. Treatment with ASA was associated with higher risk of ischaemic stroke and thrombo-embolic events compared with no antithrombotic treatment.
  
  
  CONCLUSIONS
  Acetylsalicylic acid as monotherapy in stroke prevention of atrial fibrillation has no discernable protective effect against stroke, and may even increase the risk of ischaemic stroke in elderly patients. Thus, our data support the new European guidelines recommendation that ASA as monotherapy should not be used as stroke prevention in atrial fibrillation.
authors.affiliation: Department of Public Health and Clinical Medicine, Umeå University, S-90185 Umeå, Sweden.
authors.forename: Sara
authors.initials: S
authors.lastname: Själander
authors.forename: Anders
authors.initials: A
authors.lastname: Själander
authors.forename: Peter J
authors.initials: PJ
authors.lastname: Svensson
authors.forename: Leif
authors.initials: L
authors.lastname: Friberg
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D001241:Aspirin / Q000627:therapeutic use*; D001281:Atrial Fibrillation / Q000150:complications / Q000188:drug therapy*; D002545:Brain Ischemia / Q000209:etiology / Q000517:prevention & control*; D015331:Cohort Studies; D005260:Female; D006471:Gastrointestinal Hemorrhage; D006801:Humans; D020300:Intracranial Hemorrhages; D008297:Male; D008875:Middle Aged; D010975:Platelet Aggregation Inhibitors / Q000627:therapeutic use*; D012042:Registries; D012189:Retrospective Studies; D020521:Stroke / Q000209:etiology / Q000517:prevention & control*; D013548:Sweden; D013923:Thromboembolism / Q000209:etiology / Q000517:prevention & control*; D016896:Treatment Outcome
chemical_list: D010975:Platelet Aggregation Inhibitors; D001241:Aspirin
keywords: Acetylsalicylic acid; Atrial fibrillation; Stroke