Skip to main page content
U.S. flag

An official website of the United States government

Dot gov

The .gov means it’s official.
Federal government websites often end in .gov or .mil. Before sharing sensitive information, make sure you’re on a federal government site.

Https

The site is secure.
The https:// ensures that you are connecting to the official website and that any information you provide is encrypted and transmitted securely.

Access keys NCBI Homepage MyNCBI Homepage Main Content Main Navigation
. 2009 Jul 10:10:52.
doi: 10.1186/1745-6215-10-52.

A review of reporting of participant recruitment and retention in RCTs in six major journals

Merran Toerien  1 , Sara T Brookes, Chris Metcalfe, Isabel de Salis, Zelda Tomlin, Tim J Peters, Jonathan Sterne, Jenny L Donovan
Affiliations

A review of reporting of participant recruitment and retention in RCTs in six major journals

Merran Toerien et al. Trials. .

Abstract

Background: Poor recruitment and retention of participants in randomised controlled trials (RCTs) is problematic but common. Clear and detailed reporting of participant flow is essential to assess the generalisability and comparability of RCTs. Despite improved reporting since the implementation of the CONSORT statement, important problems remain. This paper aims: (i) to update and extend previous reviews evaluating reporting of participant recruitment and retention in RCTs; (ii) to quantify the level of participation throughout RCTs.

Methods: We reviewed all reports of RCTs of health care interventions and/or processes with individual randomisation, published July-December 2004 in six major journals. Short, secondary or interim reports, and Phase I/II trials were excluded. Data recorded were: general RCT details; inclusion of flow diagram; participant flow throughout trial; reasons for non-participation/withdrawal; target sample sizes.

Results: 133 reports were reviewed. Overall, 79% included a flow diagram, but over a third were incomplete. The majority reported the flow of participants at each stage of the trial after randomisation. However, 40% failed to report the numbers assessed for eligibility. Percentages of participants retained at each stage were high: for example, 90% of eligible individuals were randomised, and 93% of those randomised were outcome assessed. On average, trials met their sample size targets. However, there were some substantial shortfalls: for example 21% of trials reporting a sample size calculation failed to achieve adequate numbers at randomisation, and 48% at outcome assessment. Reporting of losses to follow up was variable and difficult to interpret.

Conclusion: The majority of RCTs reported the flow of participants well after randomisation, although only two-thirds included a complete flow chart and there was great variability over the definition of "lost to follow up". Reporting of participant eligibility was poor, making assessments of recruitment practice and external validity difficult. Reporting of participant flow throughout RCTs could be improved by small changes to the CONSORT chart.

PubMed Disclaimer

Figures

Figure 1
Figure 1
Flow of papers through the systematic review.
Figure 2
Figure 2
CONSORT diagram of reporting of participant flow.
Figure 3
Figure 3
Proposed revised CONSORT flow diagram.
See this image and copyright information in PMC

References

    1. Vist GE, Hagen KB, Devereaux PJ, Bryant D, Kristoffersen DT, Oxman AD. Systematic review to determine whether participation in a trial influences outcome. BMJ. 2005;330:1175–1181. doi: 10.1136/bmj.330.7501.1175. - DOI - PMC - PubMed
    1. Altman DG. Statistics and ethics in medical research III. How large a sample? BMJ. 1980;281:1336–1338. doi: 10.1136/bmj.281.6251.1336. - DOI - PMC - PubMed
    1. McKee M, Britton A, Black N, McPherson K, Sanderson C, Bain C. Interpreting the evidence: choosing between randomised and non-randomised studies. BMJ. 1999;319:312–315. - PMC - PubMed
    1. Wright JR, Bouma S, Dayes I, Sussman J, Simunovic MR, Levine MN, Whelan TJ. The importance of reporting patient recruitment details in phase III trials. J Clin Oncol. 2006;24:843–845. doi: 10.1200/JCO.2005.02.6005. - DOI - PubMed
    1. Devereaux PJ, Manns BJ, Ghali WA, Quan H, Guyatt GH. The reporting of methodological factors in randomized controlled trials and the association with a journal policy to promote adherence to the Consolidated Standards of Reporting Trials (CONSORT) checklist. Control Clin Trials. 2002;23:380–388. doi: 10.1016/S0197-2456(02)00214-3. - DOI - PubMed

Publication types

MeSH terms

LinkOut - more resources