Attitudes of Japanese Cardiologists Toward Anticoagulation for Nonvalvular Atrial Fibrillation and Reasons for Its Underuse

BACKGROUND: Although warfarin reduces embolic events in patients with nonvalvular atrial fibrillation (NVAF), it is used less frequently in Japan and so the aim of the present study was to determine the attitudes of Japanese cardiologists toward antithrombotic therapy for NVAF patients. METHODS AND RESULTS: Subjects were NVAF patients enrolled in a prospective study in 1999. Clinical characteristics, type of NVAF and antithrombotic therapy, risk factors for embolism, and contraindications to warfarin were analyzed. Risk factors included advanced age (>75 years), hypertension, diabetes mellitus, congestive heart failure, and prior embolic events. Contraindications to warfarin included bleeding tendency, malignant tumors and others. Among 509 patients (66.6+/-10.3 years old), 359 had at least one risk factor for embolism and of these 359 patients, 200 (55.7%) received warfarin (ie, modest adherence to the guideline for antithrombotic therapy). There were 159 patients who had at least one risk factor but did not receive warfarin; 70.4% of these received antiplatelet drugs. Contraindications were found in only 22.6% and paroxysmal nature of NVAF seemed a possible reason for non-use of warfarin in 47.2% of 159 patients. CONCLUSIONS: In Japan warfarin is not used extensively for treatment of NVAF patients having risk factors and the reasons for not using antithrombotic therapy seemed inappropriate in most of patients.