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 search strategies 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 reference set derived from 27 published systematic reviews in a broad range of clinical fields. Outcome measures were the fraction of not identified relevant studies and the reduction in the number of studies to read. RESULTS: We tested 12 search filters. Of the studies included in the systematic reviews, 2%-28% did not pass the sensitive search filters, 4%-24% did not pass the 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 a diagnostic systematic review varied from 0% to 77%. CONCLUSION: The use of methodological filters to identify diagnostic accuracy studies can lead to omission of a considerable number of relevant studies that would otherwise be included. When preparing a systematic review, it may be preferable to avoid using methodological filters.