Received: 22 June 2019
Accepted: 9 October 2019
First Online: 6 November 2019
Ethics approval and consent to participate
: Ethics approval for this study was submitted and approved through Research Ethics Committee of the First Affiliated Hospital, College of Medicine, Zhejiang University. The consent to participate is not applicable because the study design is a retrospective data collection. The Research Ethics Committee of the Hospital was responsible for administrative permissions to access the raw data.
: Not applicable.
: The authors declare that they have no competing interests.