The Effect of Low-Dose Warfarin on the Risk of Stroke in Patients with Nonrheumatic Atrial Fibrillation

To the Editor: The Boston Area Anticoagulation Trial for Atrial Fibrillation (BAATAF) demonstrates that treatment With "low dose" warfarin reduces strokes and mortality in patients with non-rheumatic atrial fibrillation.¹ This report and the two other recent randomized studies, the Atrial Fibrillation, Aspirin, Anticoagulant Study (AFASAK) from Copenhagen² and the North American Stroke Prevention in Atrial Fibrillation study (SPAF),³ agree on the benefits of administering warfarin for this condition. Vague terms such as "low dose" and "high dose" warfarin, used in the BAATAF study, must be challenged, however, when more precise means of quantifying the effect of warfarin are available.A . . .