2.3 | Study selection and data extraction
After Endnote software was used to remove duplicate studies, two
reviewers (Xiaohong Wu and Zhoushan Feng) independently selected
eligible studies and extracted data according to the inclusion
criteria.
Differences were settled by discussion and consensus. For studies with
incomplete information, if the missing data could not be obtained after
contacting the author, a group discussion was conducted to decide
whether the study should be included.