Received: 24 January 2019
Accepted: 22 January 2020
First Online: 6 March 2020
Ethics approval and consent to participate
: Ethical approval was obtained from the Ethics Committee of Liaocheng Second People’s Hospital. All procedures performed in studies involving human participants were in accordance with the ethical standards of the institutional and national research committee. Written informed consent was obtained from all individual participants included in the study.
: Not applicable.
: The authors declare that they have no competing interests.