Bleeding rates in patients older than 90 years of age on vitamin K antagonist therapy for nonvalvular atrial fibrillation

Extremely elderly patients are being treated with anticoagulant therapy with increasing frequency. We sought to assess the rates of bleeding in such patients and to carefully examine risk factors that might predict this bleeding. This was a prospective cohort study conducted from 1 January 2007 to 29 February 2008 at an anticoagulation clinic in Modena, Italy. Ninety patients, 90 years or older, among 1635 patients with nonvalvular atrial fibrillation were studied; 69 (77%) were women with a median age of 91.71 years (range 90-98). During the enrolment period, all the patients were interviewed during an ambulatory visit and were followed in the outpatient setting. Hemorrhagic, thromboembolic and fatal events over 1 year of follow-up were monitored. Six (7%) patients discontinued vitamin K antagonists (three due to bleeding, two due to noncompliance, two due to physician recommendation). Twenty-one (23%) patients died, and 35 (39%) were admitted to hospital. One patient had an intracranial hemorrhage [1%, 95% confidence interval (CI) 0.27-6.0], two patients had a major extracranial hemorrhage (2%, 95% CI 0.7-8.0). One patient had an ischemic stroke (1%, 95% CI 0.27-6.0), two patients had embolic arterial ischemia (2%, 95% CI 0.7-8.0). All the events occurred when the international normalized ratio was outside the target range, or after oral anticoagulation had been stopped. In our study of extremely elderly anticoagulated patients, we found low rates of bleeding and thromboembolism. These findings support the use of oral anticoagulants in such patients.