Funding for this research was provided by:
PhD Research Fund of the Affiliated Hospital of the Southwest Medical University (16238)
Luzhou city: Southwest Medical University Joint Project (2017LZXNYD-PO2)
Scientific Research Fund of Southwest Medical University (0930-00031081)
Received: 21 July 2019
Accepted: 23 September 2019
First Online: 16 October 2019
Ethics approval and consent to participate
: The project was examined by the ethics committee of the Affiliated Hospital of Southwest Medical University. The research content and design of the project are in line with the ethical norms. The project was agreed to carry out.
: No individual person’s data.
: The authors declare that they have no competing interests.