Received: 12 December 2019
Accepted: 3 February 2020
First Online: 14 February 2020
Ethics approval and consent to participate
: This investigation was approved by institutional review board of the First Affiliated Hospital of Dalian Medical University, Dalian, Liaoning, China. The study was conducted according to the Guidelines of the Declaration of Helsinki.
: The manuscript does not contain any individual person’s data in any form.
: The authors declare that they have no competing interests.