Objectives: The aim of this study is to determine the relative value and contribution of searching different sources to identify adverse effects data.
Methods: The process of updating a systematic review and meta-analysis of thiazolidinedione-related fractures in patients with type 2 diabetes mellitus was used as a case study. For each source searched, a record was made for each relevant reference included in the review noting whether it was retrieved with the search strategy used and whether it was available but not retrieved. The sensitivity, precision, and number needed to read from searching each source and from different combinations of sources were also calculated.
Results: There were 58 relevant references which presented sufficient numerical data to be included in a meta-analysis of fractures and bone mineral density. The highest number of relevant references were retrieved from Science Citation Index (SCI) (35), followed by BIOSIS Previews (27) and EMBASE (24). The precision of the searches varied from 0.88% (Scirus) to 41.67% (CENTRAL). With the search strategies used, the minimum combination of sources required to retrieve all the relevant references was; the GlaxoSmithKline (GSK) website, Science Citation Index (SCI), EMBASE, BIOSIS Previews, British Library Direct, Medscape DrugInfo, handsearching and reference checking, AHFS First, and Thomson Reuters Integrity or Conference Papers Index (CPI).
Conclusions: In order to identify all the relevant references for this case study a number of different sources needed to be searched. The minimum combination of sources required to identify all the relevant references did not include MEDLINE.