MAJOR HEMORRHAGIC COMPLICATIONS DURING ORAL ANTICOAGULANT-THERAPY IN A DANISH POPULATION-BASED COHORT

Objectives, To estimate the incidence of bleeding leading to death or hospital admission in out-patients treated with oral anticoagulants. D esign, Population-based historical cohort study 1 January 1992 to 31 S eptember 1994. Setting, The County of North Jutland, Denmark (488 000 inhabitants). Subjects, Six hundred and eighty-two consecutive patient s commencing oral anticoagulant therapy. Main outcome measures. Fatal bleeding or bleeding demanding hospital admission. Results. In 756 tre atment-years of follow-up, there were 45 major haemorrhagic events (6. 0 per 100 treatment-years) in 42 patients, of which seven (0.9 per 100 treatment-years) were fatal. The risk of a first major haemorrhagic e pisode was highest during the first 90 days of treatment compared with duration above one year (incidence rate ratio, IRR, 1.9; 95% CI, 0.8- 4.1). The rate was highest above the age of 60 years, 6.8 per 100 trea tment-years, compared with 2.9 per 100 treatment-years below 60 years (IRR 2.3; 95% CI, 1.0-5.6). The rate for a bleeding event was slightly higher in females than in males (IRR 1.3; 95% CI, 0.7-2.3), but did n ot vary according to type of anticoagulant drug. Conclusions. The repo rted rates of major bleeding in this routine community setting implied a higher bleeding risk than was found in randomized trials or when pa tients are monitored in specialist anticoagulation clinics.