Intracranial and fatal bleeding according to indication for long-term oral anticoagulant therapy.

Abstract

Rate of major bleeding is generally accepted as a good measure of the risks associated with anticoagulant therapy, but this may not be true if the proportion of major bleeds with the most serious consequences differs according to the indication for anticoagulant therapy. To determine whether the indication for long-term oral anticoagulant therapy influences the proportion of major bleeds that are intracranial and fatal. Two authors abstracted intracranial and fatal bleeds from randomized trials of patients who received anticoagulant therapy for a minimum of 6months for atrial fibrillation, ischemic heart disease, venous thromboembolism, prosthetic heart valves and ischemic stroke. There were 877 major bleeds among 23,518 patients in 39 studies. The proportion of bleeds that were intracranial was significantly higher in patients with ischemic stroke (36%; 95% CI, 22-52%; P=0.02) compared with patients with venous thromboembolism (10%; 95% CI, 5-20%). The difference in the proportion of bleeds that were intracranial among atrial fibrillation, ischemic heart disease, venous thromboembolism and prosthetic heart valves was not statistically significant; however, the estimates varied from 10% to 27%. The proportion of bleeds that were fatal did not differ significantly according to indication, but varied from 8% to 20%. For all indications for anticoagulation, intracranial bleeds were much more likely to be fatal than extracranial major bleeds (44% vs. 4% overall). In current practise, the indication for oral anticoagulant therapy has limited influence on the proportion of major bleeds that are intracranial or fatal.