A case study of pooled-studies publications indicated potential for both valuable information and bias.


Journal Article (Review)

OBJECTIVES: Pooled-studies publications (PSPs) present statistical analyses of multiple randomized controlled trials without a systematic literature search or critical appraisal. We explored the characteristics of PSPs and their potential impact on a systematic review (SR). STUDY DESIGN AND SETTING: We systematically evaluated PSPs excluded from an SR of second-generation antidepressants. We analyzed their basic characteristics, risk of bias, and the effect of new data on review conclusions. RESULTS: We identified 57 PSPs containing a median of five trials (range, 2-11) and 1,233 patients (range, 117-2,919). Ninety-six percent of PSPs were industry funded, and 49% of PSPs contained unpublished data. The median number of citations for PSPs was 29 (range, 0-549). Only 7% planned pooling a priori, and 19% combined trials with identical protocols. Fifty-nine percent of PSPs eligible for general efficacy provided no new data. For some subgroups and accompanying symptoms (e.g., anxiety, insomnia, melancholia, fatigue, sex, and race), more than 30% of PSPs presented entirely new data or data that could alter the strength of the evidence available in the SR. CONCLUSION: In this case study, PSPs provided new information on subgroups and secondary outcomes; however, guidance for reviewers and development of a system to assess their susceptibility to bias are required.

Full Text

Cited Authors

  • Thaler, KJ; Morgan, LC; Van Noord, M; Jonas, DE; McDonagh, MS; Peterson, K; Glechner, A; Gartlehner, G

Published Date

  • October 2013

Published In

Volume / Issue

  • 66 / 10

Start / End Page

  • 1082 - 1092

PubMed ID

  • 23850407

Pubmed Central ID

  • 23850407

Electronic International Standard Serial Number (EISSN)

  • 1878-5921

International Standard Serial Number (ISSN)

  • 0895-4356

Digital Object Identifier (DOI)

  • 10.1016/j.jclinepi.2013.05.002


  • eng