Text and Data Mining valid from 2020-04-15
Received: 7 August 2019
Accepted: 7 April 2020
First Online: 15 April 2020
Ethics approval and consent to participate
: The study has gotten approval from Medical Ethics Committee of Nanfang hospital. Consent to participate is not applicable for this retrospective study.
: This section is not applicable for our study.
: The authors declare that they have no competing interests.