Reporting of participant flow diagrams in published reports of randomized trials

BackgroundReporting of the flow of participants through each stage of a randomized trial is essential to assess the generalisability and validity of its results. We assessed the type and completeness of information reported in CONSORT (Consolidated Standards of Reporting Trials) flow diagrams published in current reports of randomized trials.MethodsA cross sectional review of all primary reports of randomized trials which included a CONSORT flow diagram indexed in PubMed core clinical journals (2009). We assessed the proportion of parallel group trial publications reporting specific items recommended by CONSORT for inclusion in a flow diagram.ResultsOf 469 primary reports of randomized trials, 263 (56%) included a CONSORT flow diagram of which 89% (237/263) were published in a CONSORT endorsing journal. Reports published in CONSORT endorsing journals were more likely to include a flow diagram (62%; 237/380 versus 29%; 26/89). Ninety percent (236/263) of reports which included a flow diagram had a parallel group design, of which 49% (116/236) evaluated drug interventions, 58% (137/236) were multicentre, and 79% (187/236) compared two study groups, with a median sample size of 213 participants. Eighty-one percent (191/236) reported the overall number of participants assessed for eligibility, 71% (168/236) the number excluded prior to randomization and 98% (231/236) the overall number randomized. Reasons for exclusion prior to randomization were more poorly reported. Ninety-four percent (223/236) reported the number of participants allocated to each arm of the trial. However, only 40% (95/236) reported the number who actually received the allocated intervention, 67% (158/236) the number lost to follow up in each arm of the trial, 61% (145/236) whether participants discontinued the intervention during the trial and 54% (128/236) the number included in the main analysis.ConclusionsOver half of published reports of randomized trials included a diagram showing the flow of participants through the trial. However, information was often missing from published flow diagrams, even in articles published in CONSORT endorsing journals. If important information is not reported it can be difficult and sometimes impossible to know if the conclusions of that trial are justified by the data presented.

[1]  Robert Brian Haynes,et al.  Retrieving randomized controlled trials from medline: a comparison of 38 published search filters. , 2009, Health information and libraries journal.

[2]  B. Thiers,et al.  Eligibility Criteria of Randomized Controlled Trials Published in High-Impact General Medical Journals: A Systematic Sampling Review , 2008 .

[3]  M Egger,et al.  Value of flow diagrams in reports of randomized controlled trials. , 2001, JAMA.

[4]  C. Fall,et al.  Reporting of participant compliance in randomized controlled trials of nutrition supplements during pregnancy. , 2009, Maternal & child nutrition.

[5]  D. Moher,et al.  CONSORT 2010 statement: Updated guidelines for reporting parallel group randomised trials , 2010, Journal of pharmacology & pharmacotherapeutics.

[6]  A. Kiss,et al.  Eligibility criteria of randomized controlled trials published in high-impact general medical journals: a systematic sampling review. , 2007, JAMA.

[7]  D. Moher,et al.  Endorsement of the CONSORT Statement by high impact factor medical journals: a survey of journal editors and journal 'Instructions to Authors' , 2008, Trials.

[8]  D. Rennie.  CONSORT revised--improving the reporting of randomized trials. , 2001, JAMA.

[9]  Sara T Brookes,et al.  A review of reporting of participant recruitment and retention in RCTs in six major journals , 2009, Trials.

[10]  D. Moher,et al.  Does the CONSORT checklist improve the quality of reports of randomised controlled trials? A systematic review , 2006, The Medical journal of Australia.

[11]  D. Altman,et al.  CONSORT statement: extension to cluster randomised trials , 2004, BMJ : British Medical Journal.

[12]  C. Gross,et al.  Reporting the Recruitment Process in Clinical Trials: Who Are These Patients and How Did They Get There? , 2002, Annals of Internal Medicine.

[13]  C. Sabin.  Clinical trials: a practical guide to design, analysis and reporting , 2006 .

[14]  T. Whelan,et al.  The importance of reporting patient recruitment details in phase III trials. , 2006, Journal of clinical oncology : official journal of the American Society of Clinical Oncology.

[15]  D. Moher,et al.  Extending the CONSORT statement to randomized trials of nonpharmacologic treatment: explanation and elaboration. , 2008, Annals of internal medicine.

[16]  D. Moher,et al.  CONSORT 2010 Explanation and Elaboration: updated guidelines for reporting parallel group randomised trials , 2010, BMJ : British Medical Journal.

[17]  A. Oxman,et al.  Systematic review to determine whether participation in a trial influences outcome , 2005, BMJ : British Medical Journal.

[18]  Sally Hopewell,et al.  The quality of reports of randomised trials in 2000 and 2006: comparative study of articles indexed in PubMed , 2010, BMJ : British Medical Journal.