Grant: Travel Awards - Institute Community Support

Atrial fibrillation is a heart condition that increases the chance of stroke in elderly individuals, and this can be prevented through anticoagulation, or blood-thinning. Too much blood-thinning, however, can lead to bleeding and death. Currently, there are several criteria that are used to define major bleeding in clinical studies involving blood-thinners, but there is significant variability between these definitions. Rates of major bleeding are used in clinical reports of new blood-thinner drugs, and are used to inform discussion about starting blood-thinners between patients and clinicians. Therefore, understanding the clinical outcomes of different major bleeding definitions used in clinical studies is very important. In this study, we sought to find out 1) the agreement of cases identified by the three most commonly used major bleeding definitions in clinical studies involving blood-thinners; and 2) whether clinical outcomes of cases defined as major bleeding by the three definitions are the same. Using a review of over 2000 cases of bleeding associated with blood-thinners available in a clinical database, we found that there is significant differences in cases identified by the three major bleeding criteria. Furthermore, even though patients identified as major bleeding had high rates of death at 30 days (17-29% based on the definition), up to 10% of patients not identified as having major bleeding also died within 30 days. We conclude that major bleeding definitions need to be improved to identify additional patients coming to hospital with major bleeding who are at risk of death.