Interpretation
Our findings demonstrate the COMET register to be a comprehensive and
up-to-date resource for COS developers and users to identify completed
COS. Not all relevant COS were identified within our search which was
limited to Pregnancy and Childbirth or Neonatal health
categories despite being registered within other health areas. We
recommend using a broad search strategy within COMET to avoid missing
relevant COS. The CROWN register was less current. We hope our findings
will be used to update this important discipline-specific resource.
While core outcome set methodology is in its infancy, exponential growth
in COS development signifies an overwhelming commitment to the
methodology as a strategy to address variation and research wastage. The
recent publishing of COS-STAD minimum standards8 and
COS-STAR reporting guidelines18 indicate a positive
impact on COS development over the past three years, with COS being
developed with increasing rigor. Many recent COS include published
and/or registered protocols and systematic reviews improving the
transparency of the project. While COMET registration is not yet
mandated, prospective registration of planned COS projects outlininga priori the COS-STAD criteria could further improve transparency
and is recommended.
Our review found similar limitations even in the most recent COS. To be
relevant COS must include outcomes relevant to patients, clinicians and
other stakeholders.7 The initial list of outcomes must
then be generated taking all views into account. Patient views were not
included in a significant number of outcome lists. Since most COS are
funded, it is important that funding be allocated to address this
neglected area to ensure COS are truly relevant.
To be effective, COS must be implemented in practice.7To optimise implementation, COS should be generally relevant. Inclusive
stakeholder participation is an important consideration in COS
development to facilitate wide implementation. Similar to the most
recent annual review 5 patient participation was not
considered in some COS (participation: 71% vs 69%, respectively). In
others, patient attrition rates were high despite large recruited
samples. COS developers need to identify strategies to improve retention
in this stakeholder group. Similar to the most recent
review,5 while most participants in the current study
had international representation, low and middle-low income countries
were poorly represented. This was despite median country representation
being significantly higher in maternal and neonatal COS compared to
general COS development (Mdn = 26 vs Mdn = 10).5Without diverse representation, COS may not be relevant in these
countries. COS developers should identify strategies aimed at both
improving and maintaining representation from these countries to improve
global applicability of COS.14
Lastly, only two of the 26 COS specific to maternal and neonatal health
included recommendations for measurement of outcomes. While core outcome
set development focuses primarily on outcome generation, there is a
danger that a lack of attention in determining how and when outcomes are
measures will continue to contribute to ongoing variation in outcome
reporting. A joint initiative by the COMET and COSMIN (Consensus-based
Standards for the selection of health Measurement Instruments)
initiatives provides guidance for selecting outcome measures in
COS.41 COS developers are encouraged to include timely
recommendations to address this gap in knowledge. Strategies to
harmonise outcome measurement is an important consideration and may
require concerted efforts in the future to address the issue.