Abstract 17598: More Than One in Five Older Veterans are Hospitalized for Bleeding Following Initiation of Warfarin for Atrial Fibrillation

Introduction: Clinicians are hesitant to prescribe oral anticoagulants to older adults with atrial fibrillation (AF) due to concerns over bleeding risk. Hypothesis: As many data on bleeding events are from trials of rigorously selected patients, we hypothesized that major bleeding events (requiring hospitalization) would be more common than previously reported. Methods: We created a retrospective cohort of 31,951 Veterans with AF aged ≥75 years who were new referrals to VA anticoagulation clinics (warfarin) from 1/1/02 - 12/31/12. Patients with comorbid conditions requiring warfarin (e.g. pulmonary embolus) were excluded. Data were extracted from the VA electronic medical record and linked with Medicare claims data for subsequent hospitalizations. The primary outcome was any hospitalization for bleeding. We identified bleeding subtypes by source, and compared characteristics of patients with and without bleeding hospitalizations. Results: Mean population age was 81.1 years, 98.1% were male, and 8.4% were nonwhite. Over a median follow-up period of 2.62 years, 7288 patients (22.8%) were hospitalized for bleeding. There were 12,004 total bleeding events; overall, 980 (13.4%) patients experienced multiple events. The most common bleeding sources (first event) were gastrointestinal (50.8%), genitourinary (21.6%), and intracranial (9.4%) (Figure). The median time to first bleeding event was 1.59 years. Patients hospitalized for bleeding were more likely to have coronary disease (48.4% vs. 40.9%, P Conclusions: After initiating warfarin, over one in five older Veterans are hospitalized for bleeding, most commonly from a gastrointestinal source. Comorbidity burden and labile INR place these patients at increased risk.