The incidence of bleeding complications associated with warfarin treatment in general practice in the United Kingdom.

The aim of this study was to estimate and explore the incidence of warfarin-related bleeding in a representative sample of patients in the United Kingdom. We identified 3958 patients aged 40 to 84 years, newly treated with warfarin and with no prior history of bleeding from the General Practice Research Database, and followed them for 12 months. The overall incidence of first-time, idiopathic bleeding was 15.2 per 100 patient-years of current warfarin exposure: the incidence of fatal/hospitalised and referred bleeding was 3.5 and 2.6 per 100 patient-years, respectively.