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Compliance of Veterinary Medicine Systematic Reviews with Literature Search Reporting Standards MLA 2013 One Health - Boston Lorraine Toews MLIS Health Sciences Library, University of Calgary Alberta, Canada. Introduction .
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Compliance of Veterinary Medicine Systematic Reviews with Literature Search Reporting Standards MLA 2013 One Health - Boston Lorraine Toews MLIS Health Sciences Library, University of Calgary Alberta, Canada
Introduction “Poorly reported studies distort the available pool of research evidence and compromise its reliability.” Simera I, Kirtley S, Altman DG. Maturitas 2012 May;72(1):84-7. Reporting “deficiencies make it difficult … to evaluate the reliability of the presented findings” Simera I, Moher D, Hirst A, Hoey J, Schulz KF, Altman DG. BMC Med. 2010 Apr 26;8:24
Introduction “Searching is critical to conducting systematic reviews. Searches for systematic reviews need to be constructed to maximize recall and deal with … potentially biasing factors. Errors made in the search process may results in a biased or otherwise incomplete evidence base for the review.” Sampson M, McGowan J. Errors in search strategies were identified by type and frequency. J ClinEpidemiol. 2006 Oct;59(10):1057-63
Purpose Purpose of my study … to examine • Reporting of literature searches in systematic reviews in veterinary journals • Compliance with PRISMA reporting standard • Assess conduct of review
Methods • MEDLINE journal title search • 14 high impact veterinary journal titles • Limited to … • Titles “meta-analysis”, “systematic review” • Publication type “meta-analysis” • Published mid-2009 to December 2012
Methods: PRISMA Elements PRISMA reporting items examined … • Information sources searched • Databases • Grey literature • Full electronic search strategy • Limits • Publication date • Language • Article, appendix, supplementary data reviewed for PRISMA reporting elements
PRISMA: Information Sources Searched “Describe all information sources … databases with dates of coverage … in the search …”
Databases Searched Why is this important? Systematic review literature searches - comprehensive Incomplete or biased search can result in … • Biased evidence base • Inaccurate/over estimate of intervention effect
Results: Grey Literature Searched Only 32% of reviews searched for grey literature Only 24% reported searching for conference proceedings
Grey Literature Searched Why is this important? Counteract publication bias • Over half of trials in conference proceedings never published(Scherer et al. Cochrane Database Syst Rev 2007 2) • Published trials showed greater treatment effect than unpublished trials (Hopewell et al. Cochrane Database Syst Rev 2007 2) • Reviews based only on published literature risk exaggerating intervention effectiveness (Relevo et al. J ClinEpidemiol. 2011 Nov;64(11):1169)
PRISMA Search Strategy “Present full electronic search strategy for at least one database … … including any limits used … … such that it could be repeated”
Search Strategy Why is this important? Systematic review literature search aims to … • Be comprehensive • Minimize bias • Be reproducible
Search Strategy Elements High sensitivity strategies • Free-text & subject headings used • Subject headings exploded • Variant spelling, truncation Strategies customized for each database • Subject headings vary between databases • Indexing varies between databases Cochrane Handbook Pt 2 Ch 6
Results: Search Strategy 0% Line-by-line full search strategy 12% Used subject headings 0% Reported exploding subject headings 48% Limited by publication date 20% Limited by language
Conclusions • Reporting often incomplete • Not comply fully with PRISMA 12% did not report databases searched 64% did not report if grey literature searched 0% reported full electronic search strategy
Conclusions Gaps in reporting … unable to evaluate • Completeness & bias of search • Replicate search
Conclusions Reporting gaps suggest … • Conduct of searches fell short of best practices • Validity of reviews questionable … based on incomplete, biased search
Thank you for listening … Questions?