Text and Data Mining valid from 2020-04-29
Received: 21 January 2020
Accepted: 23 April 2020
First Online: 29 April 2020
Ethics approval and consent to participate
: The study was approved by the Ethics Committee of Shouguang People’s Hospital and Health Commission of Weifang City (wfwsjk_2019_188). All participants in the study were voluntary and provided written informed consent.
: Not applicable.
: The authors declare that they have no competing interests.