Core Outcome Measures in Perioperative and Anaesthetic Care (COMPAC)

There is currently no agreement or consensus within the anaesthetic and perioperative research community regarding what outcomes are important, nor how to measure them. This results in heterogeneity of outcome reporting in randomised controlled trials (RCTs), which limits the validity of comparing or combining results from RCTs in systematic reviews, and selective outcome reporting – i.e. a tendency to emphasise only outcomes of statistical or clinical significance. Standardising outcome measurement in Anaesthesia and Perioperative Medicine trials would aid in addressing these inconsistencies, and facilitate comparison and interpretation of results from RCTs involving patients undergoing major surgery.

Clearly defined perioperative outcomes are fundamental to clinical practice for the following reasons:
1) Informed clinical decision making relies on accurate data regarding the risks and benefits of a given procedure
2) Informed consent similarly presupposes a patient to have access to accurate, robustly defined information
3) Meaningful comparison between individual practitioners, teams and institutions requires the same outcomes to be measured across the board
4) Effective organisation of perioperative healthcare resources should be informed by precise outcome measures


Health Services Research Centre of the National Institute of Academic Anaesthesia (Royal College of Anaesthetists)
Surgical Outcomes Research Centre (SOuRCe) at University College Hospital, London

Prof M.P. Grocott (principal investigator)
Prof P Myles (principal investigator)
Dr R Moonesinghe
Dr O Boney

Further Study Information

Current Stage: Ongoing
Date: July 2014 - 2017
Funding source(s): National Institute of Academic Anaesthesia

Health Area

Disease Category: Anaesthesia & pain control

Disease Name: N/A

Target Population

Age Range: 18 - 100

Sex: Either

Nature of Intervention: Postoperative management , Surgery

Stakeholders Involved

- Academic research representatives
- Clinical experts
- Consumers (patients)
- Policy makers
- Service providers

Study Type

- COS for clinical trials or clinical research
- Systematic review of outcomes measured in trials


- Delphi process
- Interview
- Survey
- Systematic review

The process of developing a Core Outcome Set for anaesthesia and perioperative medicine will involve the following stages:
3.1 Identifying relevant stakeholders (patients, healthcare professionals, academic researchers, and health service managers)
3.2 Identifying all outcomes of anaesthesia, surgery and perioperative care of potential interest to relevant stakeholders
3.3 Using iterative Delphi methodology to achieve consensus among stakeholders regarding what outcomes should be included in the eventual Core Outcome Set
3.4 Publicising and encouraging the adoption of the Core Outcome Set in future anaesthetic and perioperative medicine research

‘Core Outcomes’ definition:
All generic perioperative outcomes, i.e. any that may be considered relevant to all patients undergoing major surgery, will be included as potential ‘core outcomes’. Hence generic outcomes (e.g. mortality) will be included; surgery-specific outcomes (e.g. bile leak following hepatobiliary surgery) will not. Outcomes that, though clearly associated with certain types of surgery (e.g. arrhythmias following cardiothoracic surgery) may affect any patient after surgery, will be included for consideration in subsequent stages of the Delphi consensus process.

Identifying potential core outcomes:
1) We will undertake systematic reviews of recent randomised controlled trials and prospective longitudinal trials in anaesthesia, surgery and perioperative medicine which report any generic outcomes that could be considered potential ‘core’ outcomes. Database searches of EMBASE, Medline, and the Cochrane Library will be employed to retrieve relevant trials from a fifteen month period from January 2013 to March 2014, and generic outcomes will be extracted. These outcomes will be entered into a database. Two systematic reviews will be conducted:
- one describing the range of generic clinical outcomes reported in the recent anaesthetic and surgical literature, and how those outcomes are variously measured
- one describing the range of generic patient-reported outcomes reported in the recent literature

2) We will seek views from patients and the public regarding what constitute important outcomes following surgery and anaesthesia. Views will be sought via:
- an online survey
- interviews of patients in outpatient pre-assessment clinics (i.e. pre-operatively)
- interviews of patients in outpatient follow-up clinics (i.e. postoperatively)

3) We will seek views from healthcare professionals, and from healthcare managers and policy makers, on important outcomes from the process of surgery. This will likely involve free-text surveys or face-to-face interviews.

From these sources, we will generate a comprehensive database of all commonly used perioperative outcome measures – both clinical and patient-reported – classified by domain.