Research Methods & Reporting

The PRISMA statement for reporting systematic reviews and meta-analyses of studies that evaluate healthcare interventions: explanation and elaboration

BMJ 2009; 339 doi: 10.1136/bmj.b2700 (Published 21 July 2009)
Cite this as: BMJ 2009;339:b2700
  1. Alessandro Liberati12,
  2. Douglas G Altman3,
  3. Jennifer Tetzlaff4,
  4. Cynthia Mulrow5,
  5. Peter C Gøtzsche6,
  6. John P A Ioannidis7,
  7. Mike Clarke89,
  8. P J Devereaux10,
  9. Jos Kleijnen1112,
  10. David Moher413
  1. 1Università di Modena e Reggio Emilia, Modena, Italy
  2. 2Centro Cochrane Italiano, Istituto Ricerche Farmacologiche Mario Negri, Milan, Italy
  3. 3Centre for Statistics in Medicine, University of Oxford, Oxford
  4. 4Ottawa Methods Centre, Ottawa Hospital Research Institute, Ottawa, Ontario, Canada
  5. 5Annals of Internal Medicine, Philadelphia, Pennsylvania, USA
  6. 6Nordic Cochrane Centre, Copenhagen, Denmark
  7. 7Department of Hygiene and Epidemiology, University of Ioannina School of Medicine, Ioannina, Greece
  8. 8UK Cochrane Centre, Oxford
  9. 9School of Nursing and Midwifery, Trinity College, Dublin, Republic of Ireland
  10. 10Departments of Medicine, Clinical Epidemiology and Biostatistics, McMaster University, Hamilton, Ontario, Canada
  11. 11Kleijnen Systematic Reviews, York
  12. 12School for Public Health and Primary Care (CAPHRI), University of Maastricht, Maastricht, Netherlands
  13. 13Department of Epidemiology and Community Medicine, Faculty of Medicine, Ottawa, Ontario, Canada
  1. Correspondence to: alesslib{at}mailbase.it
  • Accepted 5 June 2009

Abstract

Systematic reviews and meta-analyses are essential to summarise evidence relating to efficacy and safety of healthcare interventions accurately and reliably. The clarity and transparency of these reports, however, are not optimal. Poor reporting of systematic reviews diminishes their value to clinicians, policy makers, and other users.

Since the development of the QUOROM (quality of reporting of meta-analysis) statement—a reporting guideline published in 1999—there have been several conceptual, methodological, and practical advances regarding the conduct and reporting of systematic reviews and meta-analyses. Also, reviews of published systematic reviews have found that key information about these studies is often poorly reported. Realising these issues, an international group that included experienced authors and methodologists developed PRISMA (preferred reporting items for systematic reviews and meta-analyses) as an evolution of the original QUOROM guideline for systematic reviews and meta-analyses of evaluations of health care interventions.

The PRISMA statement consists of a 27-item checklist and a four-phase flow diagram. The checklist includes items deemed essential for transparent reporting of a systematic review. In this explanation and elaboration document, we explain the meaning and rationale for each checklist item. For each item, we include an example of good reporting and, where possible, references to relevant empirical studies and methodological literature. The PRISMA statement, this document, and the associated website (www.prisma-statement.org/) should be helpful resources to improve reporting of systematic reviews and meta-analyses.

Footnotes

  • The following people contributed to this paper: Doug Altman, Centre for Statistics in Medicine (Oxford, UK); Gerd Antes, University Hospital Freiburg (Freiburg, Germany); David Atkins, Health Services Research and Development Service, Veterans Health Administration (Washington DC, USA); Virginia Barbour, PLoS Medicine (Cambridge, UK); Nick Barrowman, Children’s Hospital of Eastern Ontario (Ottawa, Canada); Jesse A Berlin, Johnson & Johnson Pharmaceutical Research and Development (Titusville NJ, USA); Jocalyn Clark, PLoS Medicine (at the time of writing, BMJ, London); Mike Clarke, UK Cochrane Centre (Oxford, UK) and School of Nursing and Midwifery, Trinity College (Dublin, Ireland); Deborah Cook, Departments of Medicine, Clinical Epidemiology and Biostatistics, McMaster University (Hamilton, Canada); Roberto D’Amico, Università di Modena e Reggio Emilia (Modena, Italy) and Centro Cochrane Italiano, Istituto Ricerche Farmacologiche Mario Negri (Milan, Italy); Jonathan J Deeks, University of Birmingham (Birmingham); P J Devereaux, Departments of Medicine, Clinical Epidemiology and Biostatistics, McMaster University (Hamilton, Canada); Kay Dickersin, Johns Hopkins Bloomberg School of Public Health (Baltimore MD, USA); Matthias Egger, Department of Social and Preventive Medicine, University of Bern (Bern, Switzerland); Edzard Ernst, Peninsula Medical School (Exeter, UK); Peter C Gøtzsche, Nordic Cochrane Centre (Copenhagen, Denmark); Jeremy Grimshaw, Ottawa Hospital Research Institute (Ottawa, Canada); Gordon Guyatt, Departments of Medicine, Clinical Epidemiology and Biostatistics, McMaster University; Julian Higgins, MRC Biostatistics Unit (Cambridge, UK); John P A Ioannidis, University of Ioannina Campus (Ioannina, Greece); Jos Kleijnen, Kleijnen Systematic Reviews (York, UK) and School for Public Health and Primary Care (CAPHRI), University of Maastricht (Maastricht, Netherlands); Tom Lang, Tom Lang Communications and Training (Davis CA, USA); Alessandro Liberati, Università di Modena e Reggio Emilia (Modena, Italy) and Centro Cochrane Italiano, Istituto Ricerche Farmacologiche Mario Negri (Milan, Italy); Nicola Magrini, NHS Centre for the Evaluation of the Effectiveness of Health Care—CeVEAS (Modena, Italy); David McNamee, Lancet (London, UK); David Moher, Ottawa Methods Centre, Ottawa Hospital Research Institute (Ottawa, Canada); Lorenzo Moja, Centro Cochrane Italiano, Istituto Ricerche Farmacologiche Mario Negri; Maryann Napoli, Center for Medical Consumers (New York, USA); Cynthia Mulrow, Annals of Internal Medicine (Philadelphia, Pennsylvania, US); Andy Oxman, Norwegian Health Services Research Centre (Oslo, Norway); Ba’ Pham, Toronto Health Economics and Technology Assessment Collaborative (Toronto, Canada) (at the time of first meeting of the group, GlaxoSmithKline Canada, Mississauga, Canada); Drummond Rennie, University of California San Francisco (San Francisco CA, USA); Margaret Sampson, Children’s Hospital of Eastern Ontario (Ottawa, Canada); Kenneth F Schulz, Family Health International (Durham NC, USA); Paul G Shekelle, Southern California Evidence Based Practice Center (Santa Monica CA, USA); Jennifer Tetzlaff, Ottawa Methods Centre, Ottawa Hospital Research Institute (Ottawa, Canada); David Tovey, Cochrane Library, Cochrane Collaboration (Oxford, UK) (at the time of first meeting of the group, BMJ, London); Peter Tugwell, Institute of Population Health, University of Ottawa (Ottawa, Canada).

  • Lorenzo Moja helped with the preparation and the several updates of the manuscript and assisted with the preparation of the reference list. AL is the guarantor of the manuscript.

  • Competing interests: None declared.

  • Provenance and peer review: Not commissioned; externally peer reviewed.

  • In order to encourage dissemination of the PRISMA statement, this article is freely accessible on bmj.com and will also be published in PLoS Medicine, Annals of Internal Medicine, Journal of Clinical Epidemiology, and Open Medicine. The authors jointly hold the copyright of this article. For details on further use, see the PRISMA website (www.prisma-statement.org/).

This is an open-access article distributed under the terms of the Creative Commons Attribution Non-commercial License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

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