Incidence of Ischemic Stroke in Japanese Patients With Atrial Fibrillation Not Receiving Anticoagulation Therapy

– Pooled Analysis of the Shinken Database, J-RHYTHM Registry, and Fushimi AF Registry –

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Background:The incidence rate of ischemic stroke in Japanese non-valvular atrial fibrillation (NVAF) patients without anticoagulation therapy remains unclear.Methods and Results:We performed a pooled analysis of 3,588 patients from the Shinken Database (n=1,099), J-RHYTHM Registry (n=1,002), and Fushimi AF Registry (n=1,487) to determine the incidence rate of ischemic stroke in Japanese NVAF patients without anticoagulation therapy. Average patient age was 68.1 years. During the follow-up period (total, 5,188 person-years; average, 1.4 years), 69 patients suffered from ischemic stroke (13.3 per 1,000 person-years; 95% confidence intervals [CI]: 10.5–16.8). The incidence rates of ischemic stroke were 5.4, 9.3, and 24.7 per 1,000 person-years and 5.3, 5.5, and 18.4 per 1,000 person-years in patients with low (0), intermediate (1), and high (≥2) CHADS2 and CHA2DS2-VASc scores, respectively. History of ischemic stroke or transient ischemic attack (hazard ratio [HR], 3.25; 95% CI: 1.86–5.67), age ≥75 years (HR, 2.31; 95% CI: 1.18–4.52), and hypertension (HR, 1.69; 95% CI: 1.01–2.86) were independent risk factors for ischemic stroke.Conclusions:A low incidence rate of ischemic stroke was observed in Japanese NVAF patients except for those with CHADS2 score ≥2. In this pooled analysis, history of ischemic stroke or transient ischemic attack, advanced age, and hypertension were identified as independent risk factors for ischemic stroke. (Circ J 2015; 79: 432–438)