Funding for this research was provided by:
National Key Research and Development Plan (2017YFC1307705)
Received: 5 May 2019
Accepted: 19 August 2019
First Online: 27 August 2019
Ethics approval and consent to participate
: The present study was approved by the institutional review boards of Air Force Medical University (Registry no. KY20173346–1), and all studies were conducted in accordance with the ethical principles for medical research involving human subjects as defined in the Declaration of Helsinki. The consent to participate has been reviewed by the institutional review boards. This study used historical data and the consent may bring population selection bias. Patients’ privacies have been eliminated before data analyses. This study was deemed minimal risk by the boards and waiver of consent was approved.
: Not applicable.
: The authors declare that they have no competing interests.