Placebo-controlled, randomised trial of warfarin and aspirin for prevention of thromboembolic complications in chronic atrial fibrillation. The Copenhagen AFASAK study

Lancet. 1989 Jan 28;1(8631):175-9. doi: 10.1016/s0140-6736(89)91200-2.


From November, 1985, to June, 1988, 1007 outpatients with chronic non-rheumatic atrial fibrillation (AF) entered a randomised trial; 335 received anticoagulation with warfarin openly, and in a double-blind study 336 received aspirin 75 mg once daily and 336 placebo. Each patient was followed up for 2 years or until termination of the trial. The primary endpoint was a thromboembolic complication (stroke, transient cerebral ischaemic attack, or embolic complications to the viscera and extremities). The secondary endpoint was death. The incidence of thromboembolic complications and vascular mortality were significantly lower in the warfarin group than in the aspirin and placebo groups, which did not differ significantly. 5 patients on warfarin had thromboembolic complications compared with 20 patients on aspirin and 21 on placebo. 21 patients on warfarin were withdrawn because of non-fatal bleeding complications compared with 2 on aspirin and none on placebo. Thus, anticoagulation therapy with warfarin can be recommended to prevent thromboembolic complications in patients with chronic non-rheumatic AF.

Publication types

  • Clinical Trial
  • Comparative Study
  • Randomized Controlled Trial
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adult
  • Aged
  • Aged, 80 and over
  • Aspirin / administration & dosage
  • Aspirin / adverse effects
  • Aspirin / therapeutic use*
  • Atrial Fibrillation / complications*
  • Chronic Disease
  • Clinical Trials as Topic
  • Denmark
  • Double-Blind Method
  • Drug Administration Schedule
  • Female
  • Follow-Up Studies
  • Humans
  • Male
  • Middle Aged
  • Random Allocation
  • Thromboembolism / etiology
  • Thromboembolism / prevention & control*
  • Warfarin / administration & dosage
  • Warfarin / adverse effects
  • Warfarin / therapeutic use*


  • Warfarin
  • Aspirin