Funding for this research was provided by:
Key disciplinary medicine areas of Jiading Shanghai (2017ZD01)
Received: 12 December 2018
Accepted: 14 January 2019
First Online: 29 January 2019
Ethics approval and consent to participate
: Jiading district hospital ethical committee, reference number: 201803; All information obtained was kept anonymous.
: Not applicable.
: The authors declare that they have no competing interests.
: Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.