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Reporting of results from network meta-analyses: methodological systematic review

BMJ 2014; 348 doi: (Published 11 March 2014) Cite this as: BMJ 2014;348:g1741
  1. Aïda Bafeta, PhD student1,
  2. Ludovic Trinquart, postdoctoral research fellow1234,
  3. Raphaèle Seror, associate professor of rheumatology13,
  4. Philippe Ravaud, professor of epidemiology and director1234
  1. 1Assistance Publique-Hôpitaux de Paris, Centre d’Epidémiologie Clinique, INSERM U1153, Hôpital Hôtel-Dieu, 75004 Paris, France
  2. 2Université Paris Descartes-Sorbonne Paris Cité, Paris
  3. 3French Cochrane Centre, Paris
  4. 4Department of Epidemiology, Mailman School of Public Health, Columbia University, New York City, USA
  1. Correspondence to: A Bafeta aida.bafeta{at}
  • Accepted 16 February 2014


Objective To examine how the results of network meta-analyses are reported.

Design Methodological systematic review of published reports of network meta-analyses.

Data sources Cochrane Database of Systematic Reviews, Database of Abstracts of Reviews of Effects, Medline, and Embase, searched from inception to 12 July 2012.

Study selection All network meta-analyses comparing the clinical efficacy of three or more interventions in randomised controlled trials were included, excluding meta-analyses with an open loop network of three interventions.

Data extraction and synthesis The reporting of the network and results was assessed. A composite outcome included the description of the network (number of interventions, direct comparisons, and randomised controlled trials and patients for each comparison) and the reporting of effect sizes derived from direct evidence, indirect evidence, and the network meta-analysis.

Results 121 network meta-analyses (55 published in general journals; 48 funded by at least one private source) were included. The network and its geometry (network graph) were not reported in 100 (83%) articles. The effect sizes derived from direct evidence, indirect evidence, and the network meta-analysis were not reported in 48 (40%), 108 (89%), and 43 (36%) articles, respectively. In 52 reports that ranked interventions, 43 did not report the uncertainty in ranking. Overall, 119 (98%) reports of network meta-analyses did not give a description of the network or effect sizes from direct evidence, indirect evidence, and the network meta-analysis. This finding did not differ by journal type or funding source.

Conclusions The results of network meta-analyses are heterogeneously reported. Development of reporting guidelines to assist authors in writing and readers in critically appraising reports of network meta-analyses is timely.


  • We thank Elise Diard (French Cochrane Center) and Monica Serrano ( for their help with the infographics and Laura Smales for language revision of manuscript. We are particularly indebted to Josefin Blomkvist for data extraction of items on the Bayesian approach and type of prior distribution for the basic parameters and the variance.

  • Contributors: AB was involved in the study conception, search for trials, selection of trials, data extraction, data analysis, interpretation of results, and drafting the manuscript. LT was involved in the study conception, search for trials, selection of trials, interpretation of results, and drafting the manuscript. RS was involved in data extraction, interpretation of results, and drafting the manuscript. PR was involved in study conception, interpretation of results, and drafting the manuscript. PR is the guarantor.

  • Funding: AB was funded by an academic grant for doctoral students from Pierre et Marie Curie University, France. Our team is supported by an academic grant for the programme Equipe Espoirs de la Recherche, from the Fondation pour la Recherche Médicale, France. The funding agencies had no role in the design or conduct of the study; collection, management, analysis, or interpretation of the data; or preparation and review of the manuscript.

  • Competing interests: All authors have completed the ICMJE uniform disclosure form at (available on request from the corresponding author) and declare: no support from any organisation for the submitted work; no financial relationships with any organisations that might have an interest in the submitted work in the previous three years; no other relationships or activities that could appear to have influenced the submitted work.

  • Ethical approval: Not needed.

  • Transparency: PR (the manuscript’s guarantor) affirms that the manuscript is an honest, accurate, and transparent account of the study being reported; that no important aspects of the study have been omitted; and that any discrepancies from the study as planned have been explained.

  • Data sharing: No additional data available.

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