A trend analysis and search strategies for the identification of meta-analyses in MEDLINE

Article type
Authors
Wolf FM, Lefebvre C, McGaghie WC
Abstract
Objective: TO estimate

1) the growth of meta-analysis as an analytic tool for reviewing health care research findings
2) the unique and combined contributions of key word and free-text retrieval to identify a sensitive strategy for retrieving meta-analyses in the medical literature.

Methods: Meta-analysis citations were retrieved yearly over a 19 year time period and subjected to it statistical trend analysis to characterized the nature of publication trends over time. The MEDLINE database was searched from 1976 through 1994 inclusive using two independent inlet-faces. SilverPlatter and OVID. We used free-text searches of titles and abstracts and "meta-analysis" as a MeSH Heading (introduced by NLM in 1989) and as a Publication Type (introduced by NLM in 1993). Results: A combined search strategy yielded a total of 3063 citations, but at least 10% of these citations would have been missed by not using a multiple search strategy. There has been exponential growth in the number of articles published (R7 = -97, 1)<.0001), from one in 1977 to over 100 in 1988 to over 300 in 1990 and over 600 in 1994.

Results: Tile, number of citations of reports of or about meta-analysis doubled ettch year between 1987 and 1989, and tben increased each year by over 25% between 19X9 and 1992. The introduction of "meta-analysis" as a Publication Type in MEDIINE will facilitate the distinction between identifying meta-analyses per se and articles about meta-analysis. The reason that any search may under- or over estimate the true number of meta-analyses will be discussed.