3.1. Study selection
A total of 364 relevant documents were retrieved by the search methods
above, including 103 articles
from
PubMed, 96 articles from Web of Science, 66 articles from EMBASE, and 99
articles from MEDLINE. We hand-searched bibliographies of retrieved
papers and 2 article was included. After removing 248 duplicate
documents, 82
papers
were deemed ineligible after title and abstract screening, and 22 papers
were excluded after further screening through full-text reading. After
the exclusion of all the 352 unqualified studies, a total of 14
retrospective case analyses were included in this meta-analysis(10-23). The process of study selection is illustrated
in
Appendix
S1.