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

Abstract

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.