Mapping the Cochrane evidence for decision making in health care

Authors

  • Regina P. El Dib PhD,

    1. Speech, Language and Hearing Pathologist and Scientific Research Assistant of The Brazilian Cochrane Centre, PhD Postgraduate student in Internal and Therapeutic Medicine at Universidade Federal de São Paulo, The Brazilian Cochrane Centre – Universidade Federal de São Paulo, São Paulo, Brazil
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  • Álvaro N. Atallah MD PhD,

    Corresponding author
    1. Director of The Brazilian Cochrane Centre, Full Professor of Urgency Medicine and Evidence-Based Medicine at Universidade Federal de São Paulo, Brazil., The Brazilian Cochrane Centre – Universidade Federal de São Paulo, São Paulo, Brazil
      Álvaro Nagib Atallah
      The Brazilian Cochrane Centre
      Rua Pedro de Toledo, 598 – Vl. Clementino
      São Paulo – SP 04039-001
      Brazil
      E-mail: atallahmbe@uol.com.br
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  • Regis B. Andriolo

    1. Biologist and Scientific Research Assistant of The Brazilian Cochrane Centre, Postgraduate student (master) in Internal and Therapeutic Medicine at Universidade Federal de São Paulo, The Brazilian Cochrane Centre – Universidade Federal de São Paulo, São Paulo, Brazil
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Álvaro Nagib Atallah
The Brazilian Cochrane Centre
Rua Pedro de Toledo, 598 – Vl. Clementino
São Paulo – SP 04039-001
Brazil
E-mail: atallahmbe@uol.com.br

Abstract

Rationale and aim  Over the past 12 years, thousands of authors working with the Cochrane Collaboration around the world have produced systematic reviews to reduce uncertainty in health care decision making. We evaluated the conclusions from Cochrane systematic reviews of randomized controlled trials in terms of their recommendations for clinical practice and research.

Methods  In our cross-sectional study of systematic reviews published in the Cochrane Library, we randomly selected and analysed completed systematic reviews published across all 50 Cochrane Collaborative Review Groups.

Results  We analysed 1016 completed systematic reviews. Of these, 44% concluded that the interventions studied were likely to be beneficial, of which 1% recommended no further research and 43% recommended additional research. Also, 7% of the reviews concluded that the interventions were likely to be harmful, of which 2% did not recommend further studies and 5% recommended additional studies. In total, 49% of the reviews reported that the evidence did not support either benefit or harm, of which 1% did not recommend further studies and 48% recommended additional studies. Overall, 96% of the reviews recommended further research.

Conclusions  Cochrane systematic reviews were about evenly split between those in which the authors concluded that at least one of the interventions was beneficial and those in which the evidence neither supported nor refuted the intervention tested. The Cochrane Collaboration needs to include clinical trial protocol summaries with a study design optimized to answer the relevant research questions.

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