RISKS OF LONG-TERM ORAL ANTICOAGULATION IN A NON-TRIAL MEDICAL ENVIRONMENT

Randomised controlled trials have shown that anticoagulation with warf arin reduces the risk of stroke in patients with atrial fibrillation b y two thirds, However there is concern as to whether the rate of antic oagulant-related haemorrhage seen in these trials would be reproduced in a non-trial setting. Four hundred and ten consecutive patients atte nding a special anticoagulation clinic over one year were asked to com plete a questionnaire concerning their warfarin treatment, The total n umber of years on warfarin was 2870, Of the 310 patients, 59 (14%) adm itted to 88 bleeding episodes while on warfarin, Of these bleeding pro blems, 36/88 (41%) required admission to hospital or to casualty for t reatment and 52/88 (59%) required only a lowering or temporary cessati on of warfarin therapy, The calculated annual non-fatal bleeding rate of 3% in this survey is identical to that reported from the Copenhagen AFASAK trial, Similarly the 1.3% annual rate of major bleeding requir ing attendance at hospital is identical to that in the Stroke Preventi on in Non-Rheumatic Atrial Fibrillation trial, The results of this stu dy suggest that oral anticoagulation is as safe in an ordinary medical setting as in a closely supervised trial setting.