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. 2011;6(9):e25258.
doi: 10.1371/journal.pone.0025258. Epub 2011 Sep 21.

Completeness and changes in registered data and reporting bias of randomized controlled trials in ICMJE journals after trial registration policy

Mirjana Huić  1 , Matko Marušić, Ana Marušić
Affiliations

Completeness and changes in registered data and reporting bias of randomized controlled trials in ICMJE journals after trial registration policy

Mirjana Huić et al. PLoS One. 2011.

Abstract

Objective: We assessed the adequacy of randomized controlled trial (RCT) registration, changes to registration data and reporting completeness for articles in ICMJE journals during 2.5 years after registration requirement policy.

Methods: For a set of 149 reports of 152 RCTs with ClinicalTrials.gov registration number, published from September 2005 to April 2008, we evaluated the completeness of 9 items from WHO 20-item Minimum Data Set relevant for assessing trial quality. We also assessed changes to the registration elements at the Archive site of ClinicalTrials.gov and compared published and registry data.

Results: RCTs were mostly registered before 13 September 2005 deadline (n = 101, 66.4%); 118 (77.6%) started recruitment before and 31 (20.4%) after registration. At the time of registration, 152 RCTs had a total of 224 missing registry fields, most commonly 'Key secondary outcomes' (44.1% RCTs) and 'Primary outcome' (38.8%). More RCTs with post-registration recruitment had missing Minimum Data Set items than RCTs with pre-registration recruitment: 57/118 (48.3%) vs. 24/31 (77.4%) (χ(2) (1) = 7.255, P = 0.007). Major changes in the data entries were found for 31 (25.2%) RCTs. The number of RCTs with differences between registered and published data ranged from 21 (13.8%) for Study type to 118 (77.6%) for Target sample size.

Conclusions: ICMJE journals published RCTs with proper registration but the registration data were often not adequate, underwent substantial changes in the registry over time and differed in registered and published data. Editors need to establish quality control procedures in the journals so that they continue to contribute to the increased transparency of clinical trials.

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Conflict of interest statement

Competing Interests: The authors have read the journal's policy and have the following conflicts: All authors are on the Editorial Board of the Croatian Medical Journal and members of the International Committee of Medical Journal Editors (ICMJE). This does not alter the authors' adherence to all the PLoS ONE policies on sharing data and materials. The authors have declared that no competing financial interests exist.

Figures

Figure 1
Figure 1. Flow diagram of RCTs sample selection from all reports of clinical trials with ClinicalTrials.gov registration number published by ICMJE journals from 13 September 2005 to 24 April 24 2008.
See this image and copyright information in PMC

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