Background:Ischemic stroke (IS) and major bleeding, which are serious adverse events in patients with atrial fibrillation (AF), could have seasonal variations, but there are few reports.

Methods and Results:In the Shinken Database 2004–2016 (n=22,018), 3,581 AF patients (average age, 63.5 years; 2,656 men, 74.2%; 1,388 persistent AF, 38.8%) were identified. Median CHADS₂and HAS-BLED scores were both 1 point. Oral anticoagulants were prescribed for 2,082 (58.1%) patients (warfarin, 1,214; direct oral anticoagulants [DOACs], 868). Incidence and observation period (maximum 3 years) of IS, extracranial hemorrhage (ECH), and intracranial hemorrhage (ICH) were counted separately for the northern hemisphere seasons. During the mean follow-up period of 2.4 years, there were totals of 90 IS, 73 ECH, and 33 ICH cases. The respective incidence rates per 1,000 patient-years in spring, summer, autumn, and winter were 8.5, 8.8, 7.5, and 16.8 for IS, 7.2, 9.7, 3.8, and 13.1 for ECH, and 2.7, 1.9, 3.8, and 7.0 for ICH. The number of patients with DOACs relatively increased among those with ECH in summer.

Conclusions:Significant seasonal variations were observed for IS, ECH, and ICH events in AF patients, and were consistently the highest in winter. A small peak of ECH was observed in summer, which seemed, in part, to be related to increased DOAC use.

背景：缺血性中风（IS）和大出血是房颤（AF）患者的严重不良事件，可能会随季节变化，但报道很少。

方法和结果：在2004-2016年的Shinken数据库中（n = 22,018），确定了3,581名AF患者（平均年龄，63.5岁； 2,656名男性，占74.2％； 1,388名持续性AF，占38.8％）。中位数CHADS ₂HAS-BLED得分均为1分。已为2,082（58.1％）位患者开了口服抗凝药（华法令，1,214；直接口服抗凝药[DOAC]，868）。在北半球季节分别计算IS，颅外出血（ECH）和颅内出血（ICH）的发生率和观察期（最长3年）。在平均2.4年的随访期间，总共有90例IS，73例ECH和33例ICH病例。春季，夏季，秋季和冬季，每千个患者年的发病率分别为：IS，IS，E，CH分别为8.5、8.8、7.5和16.8、7.2、9.7、3.8和13.1，2.7、1.9、3.8和7.0对于ICH。在夏季，ECH患者中DOAC患者的数量相对增加。

结论： AF患者的IS，ECH和ICH事件观察到明显的季节性变化，并且始终是冬季最高的。夏季观察到ECH的峰值很小，这在某种程度上似乎与DOAC使用量增加有关。