Time trends in warfarin-associated hemorrhage.

The annual incidence of warfarin-related bleeding at Brigham and Women's Hospital increased from 0.97/1,000 patient admissions in the first time period (January 1995 to October 1998) to 1.19/1,000 patient admissions in the second time period (November 1998 to August 2002) of this study. The proportion of patients with major and intracranial bleeding increased from 20.2% and 1.9%, respectively, in the first time period, to 33.3% and 7.8%, respectively, in the second.