Searching to identify meta-analyses: it aint easy

Tags: Poster
McKibbon KA, Jadad AR, Moher M, Jones AL, Cook DJ, Tugwell P, Moher D

Introduction: Our team was funded to provide empirical evidence on several issues related to the quality assessment of reports of randomized controlled trials used in meta-analyses. To provide some useful reliability and validity to these questions we felt it was important to survey the literature as an efficient first step.

Objective: To complete an electronic search of the medical literature to identify published meta-analyses. The search was aimed at maximising recall (sensitivity) while retaining a high level of precision.

Methods: We developed search strategies to identify articles, purporting to be meta-analyses, on Medline and Embase. The search was translated, with the available controlled vocabulary, so that it could be executable in the two systems. The Medline search was completed (January 1, 1996-December 30, 1995) using the OVID search engine. The Embase search was completed January 1, 1980 to November 30, 1995) using the windows version of Silverplatter (winspirs). The search strategies included a mixture of subject indexing and free text terms.

Results: Our search strategies identified 1464 articles in Medline and 3159 articles in Embase. An initial analysis identified 425 articles from Medline that specify meta-analysis in the title. Further analysis indicates that 28% of the unspecified articles are in fact reports of meta-analysis. Additional results will be presented as will sensitivity comparisons of meta-analysis identified by both databases.

Discussion: Authors of meta-analyses should be encouraged to specify this in the title of the report.