Received: 2 January 2020
Accepted: 20 April 2020
First Online: 1 May 2020
Ethics approval and consent to participate
: This study was approved by the ethics committee of Zibo Central Hospital. Patients who participated in this research signed the informed consent and had complete clinical data. Signed written informed consents were obtained from the patients and/or guardians.
: Not applicable.
: The authors declare that they have no competing interests.