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Research Methods & Reporting

CONSORT 2010 statement: extension to randomised crossover trials

BMJ 2019; 366 doi: (Published 31 July 2019) Cite this as: BMJ 2019;366:l4378
  1. Kerry Dwan, statistical editor1,
  2. Tianjing Li, associate professor2,
  3. Douglas G Altman, professor of statistics in medicine3,
  4. Diana Elbourne, professor of healthcare evaluation4
  1. 1Review Production and Quality Unit, Editorial and Methods Department, Cochrane Central Executive, Cochrane, St Alban’s House, London SW1Y 4QX, UK
  2. 2Center for Clinical Trials and Evidence Synthesis, Department of Epidemiology, Johns Hopkins Bloomberg School of Public Health, Baltimore, MD, USA
  3. 3Centre for Statistics in Medicine, Nuffield Department of Orthopaedics, Rheumatology and Musculoskeletal Sciences, University of Oxford, Oxford, UK
  4. 4London School of Hygiene and Tropical Medicine, Department of Medical Statistics, London, UK
  1. Correspondence to: K Dwan kdwan{at}
  • Accepted 7 June 2019

Evidence shows the quality of reporting of randomised controlled trials is not optimal. The lack of transparent reporting impedes readers from judging the reliability and validity of trial findings, prevents researchers from extracting information for systematic reviews, and results in research waste. The Consolidated Standards of Reporting Trials (CONSORT) statement was developed to improve the reporting of randomised controlled trials. The primary focus of the statement was on parallel group trials with two treatment groups. Crossover trials are a particular type of trial for chronic conditions in which participants are randomised to a sequence of interventions. They are a useful and efficient design because participants act as their own control. However, the reporting of crossover trials has been variable and incomplete, which hinders their use in clinical decision making and by future researchers. We present the CONSORT extension to randomised crossover trials, which aims to facilitate better reporting of crossover trials. The CONSORT 2010 checklist is revised for crossover designs, and introduces a modified flowchart and baseline table to enhance transparency. Examples of good reporting and evidence based rationale for CONSORT crossover checklist items are provided.

Summary points

  • The Consolidated Standards of Reporting Trials (CONSORT) statement provides a minimum set of 25 items to be reported with rationale and exemplars for all randomised trials

  • CONSORT extension to crossover trials extends 14 items of the CONSORT statement

  • The use of the CONSORT extension to crossover trials will improve reporting of randomised crossover trials

Inadequate reporting of randomised controlled trials (RCTs) is associated with bias in the estimation of treatment effects12; it also impairs the critical appraisal of the quality of randomised trials, which is important when assessing the validity of the results of the individual trial and when conducting systematic reviews. To attempt to address this issue, the Consolidated Standards …

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