Empirical evidence for selective reporting of outcomes in randomized trials: comparison of protocols to published articles.
TLDR
The reporting of trial outcomes is not only frequently incomplete but also biased and inconsistent with protocols and Published articles, as well as reviews that incorporate them, may therefore be unreliable and overestimate the benefits of an intervention.Abstract:
ContextSelective reporting of outcomes within published studies based on the
nature or direction of their results has been widely suspected, but direct
evidence of such bias is currently limited to case reports.ObjectiveTo study empirically the extent and nature of outcome reporting bias
in a cohort of randomized trials.DesignCohort study using protocols and published reports of randomized trials
approved by the Scientific-Ethical Committees for Copenhagen and Frederiksberg,
Denmark, in 1994-1995. The number and characteristics of reported and unreported
trial outcomes were recorded from protocols, journal articles, and a survey
of trialists. An outcome was considered incompletely reported if insufficient
data were presented in the published articles for meta-analysis. Odds ratios
relating the completeness of outcome reporting to statistical significance
were calculated for each trial and then pooled to provide an overall estimate
of bias. Protocols and published articles were also compared to identify discrepancies
in primary outcomes.Main Outcome MeasuresCompleteness of reporting of efficacy and harm outcomes and of statistically
significant vs nonsignificant outcomes; consistency between primary outcomes
defined in the most recent protocols and those defined in published articles.ResultsOne hundred two trials with 122 published journal articles and 3736
outcomes were identified. Overall, 50% of efficacy and 65% of harm outcomes
per trial were incompletely reported. Statistically significant outcomes had
a higher odds of being fully reported compared with nonsignificant outcomes
for both efficacy (pooled odds ratio, 2.4; 95% confidence interval [CI], 1.4-4.0)
and harm (pooled odds ratio, 4.7; 95% CI, 1.8-12.0) data. In comparing published
articles with protocols, 62% of trials had at least 1 primary outcome that
was changed, introduced, or omitted. Eighty-six percent of survey responders
(42/49) denied the existence of unreported outcomes despite clear evidence
to the contrary.ConclusionsThe reporting of trial outcomes is not only frequently incomplete but
also biased and inconsistent with protocols. Published articles, as well as
reviews that incorporate them, may therefore be unreliable and overestimate
the benefits of an intervention. To ensure transparency, planned trials should
be registered and protocols should be made publicly available prior to trial
completion.read more
Citations
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Preferred reporting items for systematic reviews and meta-analyses: the PRISMA statement
TL;DR: Moher et al. as mentioned in this paper introduce PRISMA, an update of the QUOROM guidelines for reporting systematic reviews and meta-analyses, which is used in this paper.
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Preferred reporting items for systematic reviews and meta-analyses: the PRISMA Statement.
TL;DR: The QUOROM Statement (QUality Of Reporting Of Meta-analyses) as mentioned in this paper was developed to address the suboptimal reporting of systematic reviews and meta-analysis of randomized controlled trials.
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Preferred reporting items for systematic reviews and meta-analyses: The PRISMA statement
TL;DR: A structured summary is provided including, as applicable, background, objectives, data sources, study eligibility criteria, participants, interventions, study appraisal and synthesis methods, results, limitations, conclusions and implications of key findings.
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Preferred Reporting Items for Systematic Reviews and Meta-Analyses: The PRISMA Statement [in Spanish]
David Moher,Alessandro Liberati,Jennifer Tetzlaff,Douglas G. Altman,Gerd Antes,David C. Atkins,Virginia Barbour,N Barrowman,Jesse A. Berlin,J Clark,Mike Clarke,Deborah J. Cook,Roberto D'Amico,Jonathan J Deeks,Philip J. Devereaux,Kay Dickersin,M Egger,E Ernst,P C Gøtzsche,Jeremy M. Grimshaw,G Guyatt,Julian P T Higgins,Ioannidis Jpa.,Jos Kleijnen,Tom Lang,N Magrini,D McNamee,Lorenzo Moja,C Mulrow,M Napoli,Andrew D Oxman,B Pham,Drummond Rennie,Margaret Sampson,Kenneth F. Schulz,Paul G. Shekelle,David Tovey,Peter Tugwell +37 more
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The PRISMA Statement for Reporting Systematic Reviews and Meta-Analyses of Studies That Evaluate Health Care Interventions: Explanation and Elaboration
Alessandro Liberati,Douglas G. Altman,Jennifer Tetzlaff,Cynthia D. Mulrow,Peter C Gøtzsche,John P. A. Ioannidis,Mike Clarke,Mike Clarke,Philip J. Devereaux,Jos Kleijnen,David Moher +10 more
TL;DR: An Explanation and Elaboration of the PRISMA Statement is presented and updated guidelines for the reporting of systematic reviews and meta-analyses are presented.
References
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The CONSORT statement: revised recommendations for improving the quality of reports of parallel-group randomised trials
TL;DR: The revised CONSORT statement is intended to improve the reporting of an RCT, enabling readers to understand a trial's conduct and to assess the validity of its results.
Journal ArticleDOI
The Revised CONSORT Statement for Reporting Randomized Trials: Explanation and Elaboration
Douglas G. Altman,Kenneth F. Schulz,David Moher,Matthias Egger,Frank Davidoff,Diana Elbourne,Peter C Gøtzsche,Tom Lang +7 more
TL;DR: The Consort Statement as mentioned in this paper is a group of scientists and editors developed to improve the quality of reporting of randomized, controlled trials (RCTs) by providing guidance to authors about how to improve their reporting of their trials.
Book
Systematic Reviews in Health Care : Meta-Analysis in Context
TL;DR: The second edition of this best-selling book has been thoroughly revised and expanded to reflect the significant changes and advances made in systematic reviewing.
Journal ArticleDOI
The CONSORT statement: revised recommendations for improving the quality of reports of parallel group randomized trials
TL;DR: The revised CONSORT statement is intended to improve the reporting of an RCT, enabling readers to understand a trial's conduct and to assess the validity of its results.
Journal ArticleDOI
The CONSORT statement: revised recommendations for improving the quality of reports of parallel-group randomised trials
TL;DR: The revised CONSORT statement is intended to improve the reporting of an RCT, enabling readers to understand a trial's conduct and to assess the validity of its results.