Funding for this research was provided by:
Key R & D Plan of Hainan Province
Finance Science and Technology Project of Hainan Province (ZDYF2019181)
Received: 3 March 2020
Accepted: 23 April 2020
First Online: 13 May 2020
Ethics approval and consent to participate
: Informed consent was obtained from all participants and the study was approved by the Ethics Committee of the First Affiliated Hospital of Harbin Medical University.
: Not applicable.
: The authors declare that they have no competing interests.