Long-term PT-INR levels and the clinical events in the patients with non-valvular atrial fibrillation: A special reference to low-intensity warfarin therapy

Abstract Background Anticoagulation therapy is essential in atrial fibrillation (AF), and in Japan, less intense control is popular. Purpose To assess the efficacy and safety with a special reference to low intensity warfarin therapy. Subjects and methods In 488 out of 508 patients with non-valvular AF, prothrombin time-international normalized ratio (PT-INR) was kept at 1.6–2.59, and they were followed for 49.5 months: 2098 person-years. The mean age was 73.7 ± 9.9 years and 62% were male. The patients were divided by age: ≥70 years and Results Heart failure, previous stroke, and higher CHADS2 score were more often reported in patients ≥70 years while males were involved more often as younger patients. A total of 166 of 339 patients ≥70 years and 69 of 149 patients Ischemic stroke and major bleeding occurred in 1.47%/year and 1.27%/year, respectively but there was no difference between the two age groups and between the two intensities of warfarin therapy. Time in therapeutic range was a predictor for ischemic stroke. A fall of PT-INR to 2.61 in 40.0% with major bleeding at the time of the events. Blunt trauma and concomitant use of antiplatelets were risks for intracranial hemorrhage in the patients ≥70 years. Conclusions The event rates were similar between the low- (1.6–1.99) and high- (2.0–2.59) intensity warfarin therapy groups in aged patients: