Funding for this research was provided by:
National Natural Science Foundation of China (81301556)
Received: 3 July 2019
Accepted: 20 September 2019
First Online: 22 October 2019
Ethics approval and consent to participate
: The study was approved by The Medical Ethical Committee of Shandong Provincial Hospital Affiliated to Shandong University. The written informed consent was obtained from all patients included in this study.
: Not applicable.
: The authors declare that they have no competing interests.