Funding for this research was provided by:
Beijing Municipal Administration of Hospitals’ Ascent Plan (DFL20190203)
Beijing Municipal Administration of Hospitals’ Clinical Medicine Development of Special Funding Support (ZYLX201704)
High Level Health Technical Personnel of Bureau of Health in Beijing (2014-2-005)
Article History
Received: 4 January 2020
Accepted: 5 May 2020
First Online: 19 May 2020
Compliance with ethical standards
:
: The authors declare that they have no conflict of interest.
: All procedures performed in studies involving human participants were in accordance with the ethical standards of the institutional and/or national research committee and with the 1964 Helsinki Declaration and its later amendments or comparable ethical standards. For this type of study formal consent is not required.
: For this type of retrospective study formal consent is not required.