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Registered trials address questions already answered with high-certainty evidence: A sample of current redundant

Laura Vergara-Merino1, Catalina Verdejo2, Juan Victor Ariel Franco3

  • 1Cochrane Chile, Associate Centre Universidad de Valparaíso, Angamos 655, room 1111, Viña del Mar, Chile; Interdisciplinary Centre for Health Studies CIESAL, Universidad de Valparaíso, Chile; School of Medicine, Universidad de Valparaíso, Angamos 655, Viña del Mar, Chile.

Journal of Clinical Epidemiology
|February 9, 2021
PubMed
Abstract

Insights

Researchers found 39 clinical trials registered after 2015 that study primary outcomes with high certainty of evidence (CoE) already established in Cochrane reviews. This highlights ongoing research in areas with strong existing evidence.

Area of Science:

  • Evidence-based medicine
  • Systematic reviews
  • Clinical trial registration

Background:

  • Cochrane Systematic Reviews (SRs) are crucial for synthesizing research evidence.
  • The GRADE system assesses the Certainty of Evidence (CoE) for primary outcomes.
  • Identifying research gaps and redundancies is vital for efficient healthcare resource allocation.

Purpose of the Study:

  • To identify clinical trials registered after 2015.
  • To focus on primary outcomes with a pre-existing "high" Certainty of Evidence (CoE) rating from Cochrane SRs.

Main Methods:

  • Searched Cochrane Library for SRs published in 2015.
  • Extracted GRADE CoE ratings for primary outcomes from Summary of Findings (SoF) tables.
  • Searched clinical trial registries (WHO ICTRP, ClinicalTrials.gov) for studies registered post-SR publication.

Main Results:

  • Analyzed 602 SRs, identifying 81 with at least one primary outcome rated "high" CoE (totaling 152 outcomes).
  • Discovered 39 clinical trials registered for these high CoE primary outcomes.
  • Found ongoing clinical trial registration for outcomes with established high-certainty evidence.

Conclusions:

  • This study confirms the registration of clinical trials for primary outcomes where high-certainty evidence already exists.
  • Suggests potential for research duplication or the need for further investigation into the rationale for such trials.
Keywords:
Clinical trials as topicGRADEResearchSystematic reviews as topic

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