Funding for this research was provided by:
the Jiangsu Health and Family Planning Commission (Q201510)
Nature Science Foundation of Jiangsu Province (BK20171116)
Received: 12 June 2019
Accepted: 22 November 2019
First Online: 11 December 2019
Ethics approval and consent to participate
: This study was approved by the ethics committee of Nanjing Drum Tower Hospital affiliated to Medical School of Nanjing University.
: All the patients in this study have given their informed consent for the article to be published.
: The authors declare that they have no competing interests.