Core Outcome Measures in Effectiveness Trials

Developing a COS for emergency general surgery

General Information

Lay Summary
This study will initiate the work necessary to define a standard set of measures (called outcomes) that can be used to assess the how effective and safe emergency surgery is for abdominal and perianal conditions. This set of measures is called a core outcome set (COS).
Currently studies investigating emergency surgical conditions do not have a standard set of measures to assess how safe and effective the surgical care delivered is. This can make it difficult to combine the results of different studies to make decision about the best treatments. Sometimes studies may record a large number of outcomes but only describe some of these outcomes when they publish their results and this may bias what people think about a particular treatment.
A solution to these problems is the development of a core outcome set (COS). This is the minimum set of outcomes that should be studied and reported in any trial of emergency surgical care for common conditions. Using this set of outcomes in every study in this area would make it much easier combine the results of studies from different hospitals and avoid the results of a trial being biased to one type of surgical care or another because the most important outcomes for key stakeholders are consistently measured and reported.
To help develop the list of core outcomes a review of the literature in a standardised way to make a long list of all the outcomes that have been measured and written about is needed. A review of studies in this area has recently been completed by our group and the outcomes measured and described by these studies was recorded as part of this review (1). This list will be collated to produce a “Long List” of all the outcomes that healthcare professionals, researchers and policy makers think are the most important to measure in this area (a separate study will explore patients views).
Any national databases that are used to make a record of any major emergency procedures in the United Kingdom will be accessed and any outcomes that are recorded in these databases will also be noted.
Additionally, healthcare professionals, researchers and policy maker will be interviewed to assess which outcomes they consider important. (Interviews with patients will form part of a second study) Then, using a standardised scoring process (called a Delphi process) the length of the list will be reduced.
When this long list is reduced to between 10 and 30 outcomes we will hold meetings with a group of clinicians to finally reduce the list to a manageable length (a separate meeting with patients as part of a second study will also be held to produce a patient short list).
This approach will produce a final short list typically consisting of seven or eight outcomes which will form the clinician component of the core outcome set (COS). (This would later be combined with the patient short list to form the final core outcome set)

To develop a consensus amongst health professionals and policy makers of core outcomes relevant to randomised studies in emergency surgery.


1. To use data from the recent overview of systematic reviews in the six main areas of emergency general surgery (1) undertaken in the Centre of Surgical Research, University of Bristol to identify all potentially relevant clinical outcomes reported in emergency general surgery.

2. To record the outcomes collected by the National Emergency Laparotomy Audit database ( )

3. To undertake semi-structured interviews with health professionals and policy makers to identify additional outcomes that might be relevant to this clinical area.

4. To use sources (1), (2) and (3) above to create a long list of outcomes, classify these into outcome domains and operationalise these outcomes into items to use in a survey.

5. Use the survey questionnaire developed in (3) above in a Delphi consensus process followed by a consensus meeting with health professionals and policy makers to identify the core set of outcomes relevant to professional key stakeholders to evaluate emergency general surgery in RCTs.

JRE Rees1,2, Natalie S Blencowe 1,2, K Avery1, R Hinchliffe1,3, JM Blazeby1,2.

1 Centre for Surgical Research, Bristol Medical School: Population Health Sciences, University of Bristol, Canynge Hall, Bristol BS8 2PU, UK.
2 Division of Surgery, University Hospitals Bristol NHS Foundation Trust, Bristol, BS2 8HW, UK.
3 Department of Vascular Surgery, Major Arterial Centre, Brunel Building, North Bristol NHS Trust, Southmead Hospital, Westbury-on-Trym, Bristol. BS10 5NB.

Further Study Information

Current Stage:
May 2017 - December 2018
Funding source(s):
University Hospitals Bristol NHS Foundation Trust Research Capacity Funding

Health Area

Disease Category

Disease Name

Target Population

Age Range
18 - 100


Nature / type of Intervention


Consensus meeting
Delphi process
Literature review
Systematic review

Stakeholders Involved

Clinical experts
Consumers (patients)
Patient/ support group representatives
Service providers
Service users

Study Type

COS for clinical trials or clinical research
COS for practice

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