Study design and population
Patients hospitalized for AF in the First Affiliated Hospital of Zhengzhou University from January 2017 to December 2019 were registered in this retrospective cohort study. Inclusion criteria were as follows: (1) age >18 years old; (2) history of symptomatic AF for at least 6 months and documented on electrocardiogram in the previous 1 year. Exclusion criteria were as follows: (1) patients with significant coronary artery disease verified by coronary angiogram; (2) congenital heart disease, valvular heart disease and serious dysfunction of kidney and liver; (3) suffering from infectious diseases and corticosteroid or nonsteroidal anti-inflammatory drug use in the previous 6 months; (4) patients with incomplete clinical data and unwilling or unable to commit to follow up requirements. The study protocol was approved by ethics committee. Because of the retrospective design of this study, the ethics committee waived the need of obtaining informed consent from all participants.