Use of methodological search filters to identify diagnostic accuracy studies can lead to the omission of relevant studies

OBJECTIVE: To determine the usefulness of methodological filters in searchstrategies for diagnostic studies in systematic reviews.STUDY DESIGN AND SETTING: We made an inventory of existing methodological search filters for diagnostic accuracy studies and applied them in PubMed to a referenceset derived from 27 published systematic reviews in a broad range of clinicalfields. Outcome measures were the fraction of not identified relevant studies andthe reduction in the number of studies to read.RESULTS: We tested 12 search filters. Of the studies included in the systematicreviews, 2%-28% did not pass the sensitive search filters, 4%-24% did not passthe accurate filters, and 39%-42% did not pass the specific filters. Decrease in number-needed-to-read when a search filter was used in a search strategy for adiagnostic systematic review varied from 0% to 77%.CONCLUSION: The use of methodological filters to identify diagnostic accuracystudies can lead to omission of a considerable number of relevant studies thatwould otherwise be included. When preparing a systematic review, it may bepreferable to avoid using methodological filters.