Funding for this research was provided by:
Bureau of Science and Technology of Hebei Province (15277776D)
Article History
Received: 27 February 2020
Accepted: 9 June 2020
First Online: 25 June 2020
Compliance with ethical standards
:
: The authors declare that they have no conflicts of interest.
: All procedures performed in the study and involving human participants were carried out in accordance with the ethical standards of the institutional and/or national research committee and with the principles of the 1964 Declaration of Helsinki and its later amendments or comparable ethical standards. The study was approved by the Institutional Review Board of the Fourth Hospital of Hebei Medical University.
: This retrospective analysis was approved by the Institutional Review Board of the Fourth Hospital of Hebei Medical University, and the requirement of informed consent was waived.
: Not applicable.
: Not applicable.