Doctor: Youri Yordanov

Title: Avoidable waste of research in clinical trials

Supervisors: Philippe Ravaud, Agnès Dechartres

Doctoral school: ED 393 Epidemiology and Biomedical Information Sciences, Université Paris Cité

Date of thesis defense: 20/03/2019

Jury: Bertrand Guidet, Frédéric Adnet, Florence Canouï-Poitrine, Catherine Paugam, Philippe Ravaud, Agnès Dechartres


Randomized controlled trials and systematic reviews are essential for the practice of evidence- based medicine (EBM). EBM will be compromised if the evidence issued from biomedical research proves to be biased. Many authors previously denounced the poor quality of research, but in 2009 I.Chalmers and P.Glasziou integrate these criticisms into a more global concept, waste of research. It could be defined as research that fails to help patients and their clinicians to make informed decisions as without accessible, honest and usable reports, research cannot help research end users. They estimated that it could represent up to 85% of health research.

In this thesis, we focused on the avoidable waste of research in clinical trials. We had a particular interest in waste of research due to poor trial planning (trials methods or choice of outcomes) or to selective and incomplete reporting of outcomes. Then we estimated to what extent this waste could have been avoided by simple and inexpensive methodological adjustments.

Our results suggest that 1) simple and inexpensive methodological adjustments could have limited the risk of bias in 50% of clinical trials, and thus partially reduce the burden of waste of research, and 2) that many trials did not measure or report completely the important outcomes, but that this waste could have been partially avoided for the majority of the trials.

Link to download the thesis (written in French)

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