University of Groningen
Core outcome sets
Gordijn, S. J.; Ganzevoort, W.
Published in:
BJOG-an International Journal Of Obstetrics And Gynaecology
DOI:
10.1111/1471-0528.15336
IMPORTANT NOTE: You are advised to consult the publisher's version (publisher's PDF) if you wish to cite from
it. Please check the document version below.
Document Version
Publisher's PDF, also known as Version of record
Publication date:
2019
Link to publication in University of Groningen/UMCG research database
Citation for published version (APA):
Gordijn, S. J., & Ganzevoort, W. (2019). Core outcome sets: a barrier-free tool for research? BJOG-an
International Journal Of Obstetrics And Gynaecology, 126(1), 94. https://doi.org/10.1111/1471-0528.15336
Copyright
Other than for strictly personal use, it is not permitted to download or to forward/distribute the text or part of it without the consent of the author(s) and/or copyright holder(s), unless the work is under an open content license (like Creative Commons).
Take-down policy
If you believe that this document breaches copyright please contact us providing details, and we will remove access to the work immediately and investigate your claim.
Downloaded from the University of Groningen/UMCG research database (Pure): http://www.rug.nl/research/portal. For technical reasons the number of authors shown on this cover page is limited to 10 maximum.
Core outcome sets: a barrier-free tool for research?
SJ Gordijn,a W Ganzevoortb a
Obstetrics and Gynaecology, University Medical Center Groningen, University of Groningen, Groningen, the NetherlandsbObstetrics and Gynaecology, Amsterdam UMC, Amsterdam, the Netherlands
Linked article: This is a mini commentary on S Meher et al., pp. 83–93 in this issue. To view this article visit https:// doi.org/10.1111/1471-0528.15335
Published Online 28 July 2018.
The paper by Meher et al. introduces two well-defined core outcome sets (COS) for postpartum haemorrhage (PPH), one for prevention and one for treatment.
Since the launch of the COMET ini-tiative in 2010, a growing number of COS have been developed, and a sub-stantial additional number are registered on the COMET website (www.comet-initiative.org). In the field of Obstetrics and Gynaecology, a group of Journal editors initiated the CROWN initiative (www.crown-initiative.org) to highlight the need to adhere to COS: researchers should report all elements of an existing COS for trials on a topic or indicate valid reasons why they did not, in order for their manuscript to be considered for publication in these Journals.
Core outcome sets are developed with the idea to reduce waste in research by selecting those outcomes that are rel-evant and applicable in most research settings. They enforce that not only pos-itive significant findings are reported, but also relevant nonsignificant or nega-tive findings.
Do COS present another barrier to research by forcing researchers to aban-don their preferred study design? We do not think so: they explicitly do not imply that outcomes should be restricted to those in the core set. Rather, individual
studies can report any study-specific outcomes in addition. Their use facili-tates focused and relevant research by optimising comparability of data and pooled data synthesis like individual patient data meta-analysis, the highest level of evidence.
Although COS are driving forward the field of data synthesis, their use is not the only requirement for optimal comparability of studies. Standardisa-tion of ‘how’ to measure these out-comes, that is which measurement instrument to use, is also vital. For example: when considering blood loss as one of the outcomes of the PPH COS: how should it be measured? By estimation of blood loss or by weigh-ing? How to weigh (with what tool?) and correct for amniotic fluid or urine? Finally, for optimal comparability of studies, reporting baseline characteris-tics (usually mentioned in the first table of an article) should be standardised. For example: what should be reported on study population characteristics regarding health, age, socio-economic status, smoking status and alcohol intake, selected versus unselected popu-lation, etc. Therefore, the use of a mini-mum reporting set– alongside a COS– with measurement instruments would further facilitate comparison and data synthesis.
Core outcome sets (and their measurement instruments) are devel-oped through a well-described consen-sus procedure, by tapping into the common contemporary knowledge of individual participating experts, includ-ing lay experts/patient representatives. [The COMET Handbook version 1.0, Williams et al. 2017 Trials 18 (Suppl 3): 280 https://doi.org/10.1186/s13063-017-1978-4]. It must be remembered that these consensus procedures bear an inherent source of bias, related to participants and time (as new evidence may develop). It is important to carefully balance participants between stakeholder groups in order to weigh in minority opinions and prevent attrition bias (thereby overestimating agree-ment).
Consensus procedures to define min-imum items to report in studies optimise interpretation and data synthe-sis of different studies in the same research subject. They are not ‘the truth’, and their interpretation requires an overarching perspective of their limitations in order to appreciate their virtues.
Disclosure of interests
Full disclosure of interests available to view online as supporting informa-tion.&
94 ª 2018 The Authors. BJOG: An International Journal of Obstetrics and Gynaecology published by John Wiley & Sons Ltd on behalf of Royal College of Obstetricians and Gynaecologists. This is an open access article under the terms of the Creative Commons Attribution-NonCommercial License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited and is not used for commercial purposes.
