People aged over 75 in atrial fibrillation on warfarin: the rate of major hemorrhage and stroke in more than 500 patient-years of follow-up.

Objectives: To determine the incidence of major hemorrhage and stroke in people aged 76 and older with atrial fibrillation on adjusted-dose warfarin who had been recently been admitted to hospital.

Design: A retrospective observational cohort study.

Setting: A major healthcare network involving four tertiary hospitals.