Article History
Received: 30 April 2020
Accepted: 13 May 2020
First Online: 4 June 2020
Compliance with Ethical Statements
:
: None.
: The study protocol was approved by the Ethics Committee of Bozhou People’s Hospital.
: As it was a retrospective observational study, the informed consent forms by children and their guardians were waived by the committee.
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