Funding for this research was provided by:
Beijing jishuitan hospital (xkgg201810)
Article History
Received: 27 June 2019
Accepted: 6 January 2020
First Online: 18 January 2020
Ethics approval and consent to participate
: This retrospective study was approved by the Beijing Jishuitan Hospital Institutional Review Board (Beijing Jishuitan Hospital Institutional Review Board Approval Form No.201812–09) and was carried out in accordance with the ethical principles of the Declaration of Helsinki. Data were retrieved by medical records review and all activities associated with this research project were performed in accordance with Jishuitan Hospital Institutional Guidelines and Clinical Regulations. Verbal informed consent was obtained from participants or their guardians.
: Not applicable.
: The authors declare that they have no competing interests.