Triphasic Changes in Ischemic Stroke Incidence With Age in Non-Valvular Atrial Fibrillation Patients　― Pooled Analysis of the Shinken Database, J-RHYTHM Registry, and Fushimi AF Registry ―

Background: The basis for the specific age threshold for increasing of ischemic stroke in non-valvular atrial fibrillation (NVAF) patients has not been fully evaluated. Methods and Results: We conducted a pooled analysis of 3,588 Japanese NVAF patients without anticoagulation therapy from the Shinken Database (n=1,099), the J-RHYTHM Registry (n=1,002), and the Fushimi AF Registry (n=1,487) to determine the incidence of ischemic stroke by age group; patients aged between 31 and 90 years (n=3,455) were analyzed. During a follow-up period of 1.47 years, 69 ischemic strokes occurred (1.33% per year). The incidence of ischemic stroke exhibited triphasic changes as follows: first, it ranged from 0.00% per year to 0.41% per year across the age groups between 31-35 and 46-50 years. Second, it then rose to 1.58% per year in the 56-60-years age group, remaining around 1% per year across the age groups between 56-60 and 71-75 years, with rates ranging from 0.83% to 1.58% per year. Last, it further increased to 2.35% per year in the 76-80-year age group, remaining around 2.5% per year across the age groups between 76-80 and 86-90 years. Conclusions: The incidence of ischemic stroke in NVAF patients exhibits triphasic changes with age, with notable increases observed in patients aged in their late 50s and late 70s.