Searches performed in MEDLINE, Cochrane, and EMBASE databases were followed by a manual search.  The initial search retrieved 2,796 MEDLINE, 542 EMBASE, and 152 Cochrane articles, for a total of 3,490 potential articles. 
MEDLINE
Searches performed in MEDLINE, Cochrane, and EMBASE databases were followed by a manual search.  The initial search retrieved 2,796 MEDLINE, 542 EMBASE, and 152 Cochrane articles, for a total of 3,490 potential articles. 
Cochrane
Searches performed in MEDLINE, Cochrane, and EMBASE databases were followed by a manual search.  The initial search retrieved 2,796 MEDLINE, 542 EMBASE, and 152 Cochrane articles, for a total of 3,490 potential articles. 
EMBASE