Peer reviewed evaluation of registered end-points of randomised trials (the PRE-REPORT study): protocol for a stepped-wedge, cluster-randomised trial

Peer Reviewed Evaluation of Registered End-Points of Randomised Trials (the PRE-REPORT study): a stepped wedge, cluster-randomised trial

OBJECTIVE

To test whether providing relevant clinical trial registry information to peer reviewers evaluating trial manuscripts decreases discrepancies between registered and published trial outcomes.

DESIGN

Stepped wedge, cluster-randomised trial, with clusters comprised of eligible manuscripts submitted to each participating journal between 1 November 2018 and 31 October 2019.

SETTING

Thirteen medical journals.

PARTICIPANTS

Manuscripts were eligible for inclusion if they were submitted to a participating journal during the study period, presented results from the primary analysis of a clinical trial, and were peer reviewed.

INTERVENTIONS

During the control phase, there were no changes to pre-existing peer review practices. After journals crossed over into the intervention phase, peer reviewers received a data sheet describing whether trials were registered, the initial registration and enrolment dates, and the registered primary outcome(s) when enrolment began.

MAIN OUTCOME MEASURE

The presence of a clearly defined, prospectively registered primary outcome consistent with the primary outcome in the published trial manuscript, as determined by two independent outcome assessors.

RESULTS

We included 419 manuscripts (243 control and 176 intervention). Participating journals published 43% of control-phase manuscripts and 39% of intervention-phase manuscripts (model-estimated percentage difference between intervention and control trials = -10%, 95% CI -25% to 4%). Among the 173 accepted trials, published primary outcomes were consistent with clearly defined, prospectively registered primary outcomes in 40 of 105 (38%) control-phase trials and 27 of 68 (40%) intervention-phase trials. A linear mixed model did not show evidence of a statistically significant primary outcome effect from the intervention (estimated difference between intervention and control=-6% (90% CI -27% to 15%); one-sided p value=0.68).

CONCLUSIONS

These results do not support use of the tested intervention as implemented here to increase agreement between prospectively registered and published trial outcomes. Other approaches are needed to improve the quality of outcome reporting of clinical trials.

TRIAL REGISTRATION NUMBER

ISRCTN41225307.

Discrepancy review: a feasibility study of a novel peer review intervention to reduce undisclosed discrepancies between registrations and publications

Undisclosed discrepancies often exist between study registrations and their associated publications. Discrepancies can increase risk of bias, and when undisclosed, they disguise this increased risk of bias from readers. To remedy this issue, we developed an intervention called discrepancy review. We provided journals with peer reviewers specifically assigned to check for undisclosed discrepancies between registrations and manuscripts submitted to journals. We performed discrepancy review on 18 manuscripts submitted to Nicotine and Tobacco Research and three manuscripts submitted to the European Journal of Personality. We iteratively refined the discrepancy review process based on feedback from discrepancy reviewers, editors and authors. Authors addressed the majority of discrepancy reviewer comments, and there was no opposition to running a trial from authors, editors or discrepancy reviewers. Outcome measures for a trial of discrepancy review could include the presence of primary or secondary outcome discrepancies, whether publications that are not the primary report from a clinical trial registration are clearly described as such, whether registrations are permanent, and an overarching subjective assessment of the impact of discrepancies in published articles. We found that discrepancy review could feasibly be introduced as a regular practice at some journals interested in this process. A full trial of discrepancy review would be needed to evaluate its impact on reducing undisclosed discrepancies.