Appraisal of: Preston, L., et al. "Improving search efficiency for systematic reviews of diagnostic test accuracy: an exploratory study to assess the viability of limiting to MEDLINE, EMBASE and reference checking." Syst Rev 2015 4: 82.

Short description: 

A convenience sample of nine Health Technology Assessment (HTA) systematic reviews of diagnostic test accuracy, with 302 included citations, was analysed to determine the number and proportion of included citations that were indexed in and retrieved from MEDLINE and EMBASE. An assessment was also made of the number and proportion of citations not retrieved from these databases but that could have been identified from the reference lists of included citations.

287/302 (95 %) of the included citations were indexed across MEDLINE and EMBASE. The reviews’ searches of MEDLINE and EMBASE accounted for 85 % of the included citations (256/302). Of the forty-six (15 %) included citations not retrieved by the published searches, 24 (8 %) could be found in the reference lists of included citations. Only 22/302 (7 %) of the included citations were not found. 

Limitations stated by the author(s): 

This study used a small, non-random sample of diagnostic test accuracy systematic reviews. This was done for reasons of pragmatism: first, because the authors had full access to the search strategies and reference databases of these reviews and, second, because of the exploratory nature of this project. We also assumed that the vast majority of the included citations in the reviews were located through screening of titles, abstracts and full papers.

We have also assumed, because the number of studies missed by operating the proposed MEDLINE, EMBASE and reference tracking strategy is so small that the findings of the systematic reviews would not have been greatly affected by their omission. However, this is uncertain and can only be assessed statistically by excluding those particular studies from the many analyses reported in the reviews, although, as noted above, most of these reviews conducted narrative synthesis. Such an analysis is a major task to undertake retrospectively and has therefore not been completed in this exploratory study. Future work should test the findings of this small study in a larger, preferably prospective sample of systematic reviews from multiple institutions. If possible, statistical analysis should also be undertaken to quantify fully the impact of omitting any data from studies that might otherwise be missed.

Limitations stated by the reviewer(s): 
No further limitations were identified.
Study Type: 
Single study