Major hemorrhage and tolerability of warfarin in the first year of therapy among elderly patients with atrial fibrillation

Elaine M. Hylek, Carmella Evans-Molina, Carol Shea, Lori E. Henault, Susan Regan

Research output: Contribution to journalArticle

823 Scopus citations


BACKGROUND - Warfarin is effective in the prevention of stroke in atrial fibrillation but is under used in clinical care. Concerns exist that published rates of hemorrhage may not reflect real-world practice. Few patients ≥80 years of age were enrolled in trials, and studies of prevalent use largely reflect a warfarin-tolerant subset. We sought to define the tolerability of warfarin among an elderly inception cohort with atrial fibrillation. METHODS AND RESULTS - Consecutive patients who started warfarin were identified from January 2001 to June 2003 and followed for 1 year. Patients had to be ≥65 years of age, have established care at the study institution, and have their warfarin managed on-site. Outcomes included major hemorrhage, time to termination of warfarin, and reason for discontinuation. Of 472 patients, 32% were ≥80 years of age, and 91% had ≥1 stroke risk factor. The cumulative incidence of major hemorrhage for patients ≥80 years of age was 13.1 per 100 person-years and 4.7 for those <80 years of age (P=0.009). The first 90 days of warfarin, age ≥80 years, and international normalized ratio (INR) ≥4.0 were associated with increased risk despite trial-level anticoagulation control. Within the first year, 26% of patients ≥80 years of age stopped taking warfarin. Perceived safety issues accounted for 81% of them. Rates of major hemorrhage and warfarin termination were highest among patients with CHADS2 scores (an acronym for congestive heart failure, hypertension, age ≥75, diabetes mellitus, and prior stroke or transient ischemic attack) of ≥3. CONCLUSIONS - Rates of hemorrhage derived from younger noninception cohorts underestimate the bleeding that occurs in practice. This finding coupled with the short-term tolerability of warfarin likely contributes to its underutilization. Stroke prevention among elderly patients with atrial fibrillation remains a challenging and pressing health concern.

Original languageEnglish (US)
Pages (from-to)2689-2696
Number of pages8
Issue number21
StatePublished - May 1 2007
Externally publishedYes


  • Anticoagulants
  • Atrial fibrillation
  • Hemorrhage
  • Stroke

ASJC Scopus subject areas

  • Cardiology and Cardiovascular Medicine
  • Physiology (medical)

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