Network meta-analyses could be improved by searching more sources and by involving a librarian

  • Lun Li
    Affiliations
    The First Clinical College of Lanzhou University, No. 199 Donggang West Road, Lanzhou, Gansu 730000, China

    Evidence-Based Medicine Center, School of Basic Medical Sciences, No. 199 Donggang West Road, Lanzhou, Gansu 730000, China

    Clinical Epidemiology Program, Ottawa Hospital Research Institute, 501 Smyth Road, Ottawa, Ontario K1H 8L6, Canada

    Department of Epidemiology and Community Medicine, Faculty of Medicine, University of Ottawa, 451 Smyth Road, Ottawa, Ontario K1H 8M5, Canada
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  • Jinhui Tian
    Affiliations
    Evidence-Based Medicine Center, School of Basic Medical Sciences, No. 199 Donggang West Road, Lanzhou, Gansu 730000, China
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  • Hongliang Tian
    Affiliations
    The First Clinical College of Lanzhou University, No. 199 Donggang West Road, Lanzhou, Gansu 730000, China

    Evidence-Based Medicine Center, School of Basic Medical Sciences, No. 199 Donggang West Road, Lanzhou, Gansu 730000, China
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  • David Moher
    Affiliations
    Clinical Epidemiology Program, Ottawa Hospital Research Institute, 501 Smyth Road, Ottawa, Ontario K1H 8L6, Canada

    Department of Epidemiology and Community Medicine, Faculty of Medicine, University of Ottawa, 451 Smyth Road, Ottawa, Ontario K1H 8M5, Canada
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  • Fuxiang Liang
    Affiliations
    The First Clinical College of Lanzhou University, No. 199 Donggang West Road, Lanzhou, Gansu 730000, China
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  • Tongxiao Jiang
    Affiliations
    The First Clinical College of Lanzhou University, No. 199 Donggang West Road, Lanzhou, Gansu 730000, China
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  • Liang Yao
    Affiliations
    The First Clinical College of Lanzhou University, No. 199 Donggang West Road, Lanzhou, Gansu 730000, China
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  • Kehu Yang
    Correspondence
    Corresponding author. Tel.: +86-138-93117077; fax: +86-931-8915076.
    Affiliations
    The First Clinical College of Lanzhou University, No. 199 Donggang West Road, Lanzhou, Gansu 730000, China

    Evidence-Based Medicine Center, School of Basic Medical Sciences, No. 199 Donggang West Road, Lanzhou, Gansu 730000, China
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      Abstract

      Objective

      Network meta-analyses (NMAs) aim to rank the benefits (or harms) of interventions, based on all available randomized controlled trials. Thus, the identification of relevant data is critical. We assessed the conduct of the literature searches in NMAs.

      Study Design

      Published NMAs were retrieved by searching electronic bibliographic databases and other sources. Two independent reviewers selected studies and five trained reviewers abstracted data regarding literature searches, in duplicate. Search method details were examined using descriptive statistics.

      Results

      Two hundred forty-nine NMAs were included. Eight used previous systematic reviews to identify primary studies without further searching, and five did not report any literature searches. In the 236 studies that used electronic databases to identify primary studies, the median number of databases was 3 (interquartile range: 3–5). MEDLINE, EMBASE, and Cochrane Central Register of Controlled Trials were the most commonly used databases. The most common supplemental search methods included reference lists of included studies (48%), reference lists of previous systematic reviews (40%), and clinical trial registries (32%). None of these supplemental methods was conducted in more than 50% of the NMAs.

      Conclusion

      Literature searches in NMAs could be improved by searching more sources, and by involving a librarian or information specialist.

      Keywords

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