title: Systematic review of long term anticoagulation or antiplatelet treatment in patients with non-rheumatic atrial fibrillation.
abstract: OBJECTIVE
  To examine the benefits and risks of long term anticoagulation (warfarin) compared with antiplatelet treatment (aspirin/indobufen) [corrected] in patients with non-rheumatic atrial fibrillation.
  
  
  METHODS
  Meta-analysis of randomised controlled trials from Cochrane library, Medline, Embase, Cinhal, and Sigle from 1966 to December 1999. Odds ratios (95% confidence intervals) calculated to estimate treatment effects.
  
  
  METHODS
  Fatal and non-fatal cardiovascular events, reductions of which were classified as benefits. Fatal and major non-fatal bleeding events classified as risks.
  
  
  RESULTS
  No trials were found from before 1989. There were five randomised controlled trials published between 1989-99. There were no significant differences in mortality between the two treatment options (fixed effects model: odd ratio 0.74 (95% confidence interval 0.39 to 1.40) for stroke deaths; 0.86 (0.63 to 1.17) for vascular deaths). There was a borderline significant difference in non-fatal stroke in favour of anticoagulation (0.68 (0.46 to 0.99)); and 0.75 (0.50 to 1.13) after exclusion of one trial with weak methodological design. A random effects model showed no significant difference in combined fatal and non-fatal events (odds ratio 0.79 (0.61 to 1.02)). There were more major bleeding events among patients on anticoagulation than on antiplatelet treatment (odds ratio 1.45 (0.93 to 2.27)). One trial was stopped prematurely after a significant difference in favour of anticoagulation was observed. The only trial to show a significant difference in effect (favouring anticoagulation) was methodologically weaker in design than the others.
  
  
  CONCLUSIONS
  The heterogeneity between the trials and the limited data result in considerable uncertainty about the value of long term anticoagulation compared with antiplatelet treatment. The risks of bleeding and the higher cost of anticoagulation make it an even less convincing treatment option.
authors.affiliation: Bristol Heart Institute, University of Bristol, Bristol Royal Infirmary, Bristol BS2 8HW. f.c.taylor@bristol.ac.uk
authors.forename: F C
authors.initials: FC
authors.lastname: Taylor
authors.forename: H
authors.initials: H
authors.lastname: Cohen
authors.forename: S
authors.initials: S
authors.lastname: Ebrahim
mesh_terms: D000925:Anticoagulants / Q000009:adverse effects / Q000627:therapeutic use*; D001241:Aspirin / Q000009:adverse effects / Q000627:therapeutic use; D001281:Atrial Fibrillation / Q000188:drug therapy*; D006470:Hemorrhage / Q000139:chemically induced; D006801:Humans; D054833:Isoindoles; D010654:Phenylbutyrates / Q000009:adverse effects / Q000627:therapeutic use; D010975:Platelet Aggregation Inhibitors / Q000009:adverse effects / Q000627:therapeutic use*; D016032:Randomized Controlled Trials as Topic; D018570:Risk Assessment; D016896:Treatment Outcome; D014859:Warfarin / Q000009:adverse effects / Q000627:therapeutic use
chemical_list: D000925:Anticoagulants; D054833:Isoindoles; D010654:Phenylbutyrates; D010975:Platelet Aggregation Inhibitors; D014859:Warfarin; C020371:indobufen; D001241:Aspirin