Effects of the quality of warfarin therapy on the development of ischemic and hemorrhagic events in elderly Japanese patients with nonvalvular atrial fibrillation

Abstract

Purpose and Method: Among nonvalvular atrial fibrillation aged 70 or older, 512 patients (75.5±5.7 years, 198 females) taking warfarin, relationships between the time in therapeutic range (TTR) to target the international normalized ratio of 1.6–2.6, and the occurrence of ischemic or hemorrhagic events were retrospectively investigated. Results: During the total follow-up period of 36,101 months, 60 ischemic events and 30 hemorrhagic events occurred. By multivariate analysis, TTR ≥55.6% were independently associated with ischemic events (hazard ratio, 0.54; 95% CI, 0.30–0.96; p=0.037), but, TTR had no association with hemorrhagic events. Conclusion: The quality of warfarin therapy is negatively correlated with ischemic events independently.