Received: 26 August 2019
Accepted: 3 December 2019
First Online: 19 December 2019
Ethics approval and consent to participate
: The study protocol was designed following guidelines in the Declaration of Helsinki, and approved by the Ethical Committee of Shandong Provincial Hospital Affiliated to Shandong First Medical University.
: All participants have given consent for publication.Written informed consent was obtained from the participant for publication of their individual details in this manuscript. The consent form is held by the authors’ institution and is available for review by the Editor-in-Chief.
: The authors declare that they have no competing interests.