Clinical trial registration was not an indicator for low risk of bias

Farquhar, Cynthia; Showell, Marian; Showell, Emily; Beetham, Penny; Baak, Nora; Mourad, Selma; Jordan, Vanessa

doi:10.1016/j.jclinepi.2016.11.011

Cited by 40 publications

(28 citation statements)

References 28 publications

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“…Roberts et al have suggested that systematic reviews include only prospectively registered trials, under the premise that such trials are the only ones not affected by reporting bias. Registered and unregistered trials have been found to differ in their risk of bias in studies examining 326 RCTs from Latin America and the Caribbean and 693 RCTs of fertility treatments [ 44 , 62 ]. Other investigations have examined the impact of registration status on positive study findings and have not found differences between registered and non-registered trials [ 38 , 42 , 58 ].…”

Section: Discussionmentioning

confidence: 99%

Registration of published randomized trials: a systematic review and meta-analysis

Trinquart

Dunn

Bourgeois

2018

BMC Med

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BackgroundProspective trial registration is a powerful tool to prevent reporting bias. We aimed to determine the extent to which published randomized controlled trials (RCTs) were registered and registered prospectively.MethodsWe searched MEDLINE and EMBASE from January 2005 to October 2017; we also screened all articles cited by or citing included and excluded studies, and the reference lists of related reviews. We included studies that examined published RCTs and evaluated their registration status, regardless of medical specialty or language. We excluded studies that assessed RCT registration status only through mention of registration in the published RCT, without searching registries or contacting the trial investigators. Two independent reviewers blinded to the other’s work performed the selection. Following PRISMA guidelines, two investigators independently extracted data, with discrepancies resolved by consensus. We calculated pooled proportions and 95% confidence intervals using random-effects models.ResultsWe analyzed 40 studies examining 8773 RCTs across a wide range of clinical specialties. The pooled proportion of registered RCTs was 53% (95% confidence interval 44% to 58%), with considerable between-study heterogeneity. A subset of 24 studies reported data on prospective registration across 5529 RCTs. The pooled proportion of prospectively registered RCTs was 20% (95% confidence interval 15% to 25%). Subgroup analyses showed that registration was higher for industry-supported and larger RCTs. A meta-regression analysis across 19 studies (5144 RCTs) showed that the proportion of registered trials significantly increased over time, with a mean proportion increase of 27%, from 25 to 52%, between 2005 and 2015.ConclusionsThe prevalence of trial registration has increased over time, but only one in five published RCTs is prospectively registered, undermining the validity and integrity of biomedical research.Electronic supplementary materialThe online version of this article (10.1186/s12916-018-1168-6) contains supplementary material, which is available to authorized users.

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Section: Discussionmentioning

confidence: 99%

Registration of published randomized trials: a systematic review and meta-analysis

Trinquart

Dunn

Bourgeois

2018

BMC Med

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“…29,30 It has been observed that registered trials tend to have a low risk of bias for random sequence generation, allocation concealment, and selective reporting, but not blinding or incomplete outcome data. 31 Nine trials did not identify their study as a pilot in either their title or abstract. As the title and abstract are the items freely accessible to readers, it is important to be as explicit as possible.…”

Section: Summary Of Findingsmentioning

confidence: 99%

A cross-sectional study of the reporting quality of pilot or feasibility trials in high-impact anesthesia journals

Shanthanna

Kaushal

Mbuagbaw

et al. 2018

Can J Anesth/J Can Anesth

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“…This policy resulted in a dramatic increase in the number of registered trials, from about 5,600 in 2000 to 299,127 as of March 2019 (U.S. National Library of Medicine, ). These initiatives helped decreasing the risk of selective outcome reporting, since prospectively registered trials present lower risk of selective reporting (Farquhar et al., ) and registered trials are less likely to report significant results than non‐registered studies (Kaplan & Irvin, ). However, selective outcome reporting is still prominent in the literature.…”

Section: Introductionmentioning

confidence: 99%

Selective outcome reporting in randomized clinical trials of dental implants

Sendyk

Rovai

Souza

et al. 2019

J Clinic Periodontology

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Aim: Selective outcome reporting (SOR) is a type of bias that occurs when the primary outcome of a trial protocol is changed or omitted in the paper. The purpose of this study was to evaluate the prevalence of SOR in publications of randomized clinical trials (RCT) concerning dental implants. Materials and Methods:Two reviewers independently screened protocols registered at ClinicalTrials.gov until February/2019. If the protocol met the eligibility criteria, the reviewers tried to identify the corresponding publication. Data extraction was carried out by the same reviewers. Primary and secondary outcomes were recorded for each trial and compared to outcomes previously described in protocols. Results:A total of 49 protocols were included. SOR was identified in 27 (55.1%) trials.The major discrepancies were as follows: protocol-defined primary outcome omitted in the publication (n = 6, 12.2%), new primary outcome introduced (n = 8, 16.3%), discrepancy in the primary outcome time frame (n = 17, 34.7%) and new secondary outcome introduced (n = 31, 63.3%). SOR was significantly associated with industry funding (p = 0.04) and timing of registration (p = 0.04). Conclusions:Our results indicate a high rate of SOR in dental implants clinical trials.Use of registry data during the peer-review process may help decreasing SOR. K E Y W O R D S dental implant, randomized clinical trials, selective reporting | 759 SENDYK Et al. S U PP O RTI N G I N FO R M ATI O N Additional supporting information may be found online in the Supporting Information section at the end of the article. How to cite this article: Sendyk DI, Rovai ES, Souza NV, Deboni MCZ, Pannuti CM. Selective outcome reporting in randomized clinical trials of dental implants. J Clin Periodontol. 2019;46:758-765. https ://doi.

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Clinical trial registration was not an indicator for low risk of bias

Cited by 40 publications

References 28 publications

Registration of published randomized trials: a systematic review and meta-analysis

Registration of published randomized trials: a systematic review and meta-analysis

A cross-sectional study of the reporting quality of pilot or feasibility trials in high-impact anesthesia journals

Selective outcome reporting in randomized clinical trials of dental implants

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