The methods used to derive the CQ search filters in both MEDLINE and EMBASE have been described elsewhere5–9
. In this study, we compared the yield of the sensitive CQ diagnostic filters () with the studies included in a sample of systematic reviews of diagnostic accuracy from the ACP Journal Club
) for the year 2006 (search done in May, 2007).
Best sensitivity Clinical Queries for studies of diagnostic accuracy in MEDLINE and EMBASE
Diagnostic accuracy reviews were searched from the ACP Journal Club
web site by entering “Review” in the search field, and selecting “Diagnosis” from the “Article type” drop-down menu. We selected diagnostic accuracy reviews by first looking at each ACP Journal Club
page of titles for reviews that were bannered as 2006. Study eligibility was determined by looking at each 2006 diagnosis review in full-text, which was downloaded using the PubMed identifying numbers hyperlink at the end of the citation of the original study. Eligibility criteria for including a diagnostic accuracy systematic review in our study were that it was published in 2006, incorporated a MEDLINE and EMBASE search as a data source, and that the review was available and downloadable in electronic format. When the diagnostic accuracy reviews were analyzed in full-text, we discovered that the systematic review by Wardlaw et al11
used our diagnostic CQ search filter as part of their strategy. To avoid “incorporation bias”, we added this additional criterion for eligibility: the systematic review could not use the CQ search filters. The included studies of each of the eligible diagnostic systematic reviews were documented in an Excel datasheet.
For each eligible diagnostic review topic, we ran the sensitive CQ diagnostic search filter in both MEDLINE and EMBASE using the Ovid Technologies interface. Starting with MEDLINE, each of the included studies for each systematic review was located by entering citation information in the search field. Once an included study was located, the “diagnosis (sensitivity)” option in the “Limits” tab was used to test if the article would be captured by the sensitive CQ diagnostic search filter.
We assessed the effect on the conclusions of a review of any included study that was not retrieved by the sensitive search filter. We defined an included study as having a “potential impact” on the summary measures and conclusions of the systematic review if it was used as one of studies included in a meta-analysis, or if it was described in the Results section of the review in the context of any of the outcomes. For articles included in the review but not retrieved by the sensitive search filter, we defined a non-retrieved article as having “no impact” on the systematic review if the exclusion of the included study from the review’s analysis made no difference to the final conclusions compared with results if the study had been included in the analysis.
To determine if the sensitive CQ diagnostic search filter reduces the number of studies that need to be screened after searching MEDLINE and EMBASE, we sought to replicate the search filters in the systematic reviews. We contacted the authors of the systematic reviews to obtain the exact filter used in their search.