Analysis of the systematic reviews process in reports of network meta-analyses: methodological systematic reviewBMJ 2013; 347 doi: https://doi.org/10.1136/bmj.f3675 (Published 01 July 2013) Cite this as: BMJ 2013;347:f3675
- Aïda Bafeta, PhD student12,
- Ludovic Trinquart, senior statistician1234,
- Raphaèle Seror, associate professor of rheumatology124,
- Philippe Ravaud, professor of epidemiology and director12345
- 1INSERM U738 Research Unit, Paris, France
- 2Assistance Publique-Hôpitaux de Paris, Centre d’Epidémiologie Clinique, Hôpital Hôtel-Dieu, 75004 Paris, France
- 3Université Paris Descartes-Sorbonne Paris Cité, Paris, France
- 4French Cochrane Centre, Paris, France
- 5Department of Epidemiology, Mailman School of Public Health, Columbia University, New York, USA
- Correspondence to: A Bafeta
- Accepted 31 May 2013
Objective To examine whether network meta-analyses, increasingly used to assess comparative effectiveness of healthcare interventions, follow the key methodological recommendations for reporting and conduct of systematic reviews.
Design Methodological systematic review of 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.
Review methods All network meta-analyses comparing clinical efficacy of three or more interventions based on randomised controlled trials, excluding meta-analyses with an open loop network of three interventions. We assessed the reporting of general characteristics and key methodological components of the systematic review process using two composite outcomes. For some components, if reporting was adequate, we assessed their conduct quality.
Results Of 121 network meta-analyses covering a wide range of medical areas, 100 (83%) assessed pharmacological interventions and 11 (9%) non-pharmacological interventions; 56 (46%) were published in journals with a high impact factor. The electronic search strategy for each database was not reported in 88 (73%) network meta-analyses; for 36 (30%), the primary outcome was not clearly identified. Overall, 61 (50%) network meta-analyses did not report any information regarding the assessment of risk of bias of individual studies, and 103 (85%) did not report any methods to assess the likelihood of publication bias. Overall, 87 (72%) network meta-analyses did not report the literature search, searched only one database, did not search other sources, or did not report an assessment of risk of bias of individual studies. These methodological components did not differ by publication in a general or specialty journal or by public or private funding.
Conclusions Essential methodological components of the systematic review process—conducting a literature search and assessing risk of bias of individual studies—are frequently lacking in reports of network meta-analyses, even when published in journals with high impact factors.
Contributors: AB was responsible for the study conception, search of trials, selection of trials, data extraction, data analysis, interpretation of results, and drafting the manuscript. LT was responsible for the study conception, search of trials, selection of trials, interpretation of results, and drafting the manuscript. RS was responsible for the data extraction, interpretation of results, and drafting the manuscript. PR was the guarantor and was responsible for the study conception, interpretation of results, and drafting the manuscript. All authors, external and internal, had full access to all of the data (including statistical reports and tables) in the study and can take responsibility for the integrity of the data and the accuracy of the data analysis.
Funding: This study was funded by an academic grant for the doctoral student from “Pierre et Marie Curie University.” Our team is supported by an academic grant (DEQ20101221475) for the programme “Equipe espoir de la Recherche,” from the Fondation pour la Recherche Médicale. The funding agencies have 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 www.icmje.org/coi_disclosure.pdf 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: Ethical approval not required.
Data sharing: No additional data available.
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