Text and Data Mining valid from 2019-07-31
Received: 6 April 2019
Accepted: 10 July 2019
First Online: 31 July 2019
Ethics approval and consent to participate
: The study protocol was approved by the Research Ethics Commission of the First Affiliated Hospital of Anhui Medical University. Permission to carry out the study and access patient records was sought from the respective hospital administrators.
: No applicable.
: The authors declare that they have no competing interests.