Search strategy and data sources
To identify studies eligible for inclusion in this meta-analysis, we
conducted a computerized search of clinical studies in PubMed (January
1966 to August 2019), EMBASE (January 1988 to August 2019), and Cochrane
Library (database inception to August 2019). To minimize publication
bias, references cited in the text of selected articles were further
searched. Searches were performed using the keywords as Medical Subject
Headings (National Library of Medicine, Bethesda, MD, USA), EMTREE, and
natural language. Search terms used in this study were stated in the
eAppendix in the Supplement.
This study was conducted according to the Cochrane Handbook for
Systematic Reviews of Interventions 8, 9 and the
statement by the Preferred Reporting Items for Systematic Reviews and
Meta-Analyses group.10