Appraisal of: van Enst WA, Scholten RJ, Whiting P, Zwinderman AH, Hooft L. Meta-epidemiologic analysis indicates that MEDLINE searches are sufficient for diagnostic test accuracy systematic reviews. J Clin Epidemiol 2014;67(11): 1192-1199.

Short description: 

This paper describes an investigation into the impact of excluding studies which could not be retrieved from MDELINE on the summary relative diagnostic odds ratio of a diagnostic test accuracy systematic review.   The authors identified ten reviews with 15 meta-analyses which also included searches of MEDLINE and at least one other database.  The statistical analysis found that when removing studies available from databases other than MEDLINE that the summary estimates of sensitivity and specificity in the reviews remained almost unchanged.  The authors conclude that restricting to studies indexed in MEDLINE did not influence the summary estimates of the meta-analyses in the 10 reviews and it might be acceptable where resources are limited to restrict searches to MEDLINE.

Limitations stated by the author(s): 

The authors noted that a more restrictive search might miss relevant studies and decrease the power of the meta-analysis. The authors also acknowledge that searching additional databases may yield records which, while available in MEDLINE, were not retrieved by specific searches. The number of included meta-analyses was small and those that were selected were from higher impact journals.  The authors would have liked to have investigated search strategies in more detail but these were not reported in full in many reviews.  They were unable to rerun the search strategies in the reviews and had to run known-item searches which have the disadvantage that we do not know how the original searches performed.

Limitations stated by the reviewer(s): 
The authors do describe the limitations of known-item searching but do not mention this until the discussion.
Study Type: 
Single study
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