British Journal of Anaesthesia

Core Outcome Measures for Perioperative and Anaesthetic Care (COMPAC): a modified Delphi process to develop a core outcome set for trials in perioperative care and anaesthesia

Published:November 02, 2021DOI:



      Outcome selection underpins clinical trial interpretation. Inconsistency in outcome selection and reporting hinders comparison of different trials' results, reducing the utility of research findings.


      We conducted an iterative consensus process to develop a set of Core Outcome Measures for Perioperative and Anaesthetic Care (COMPAC), following the established Core Outcome Measures for Effectiveness Trials (COMET) methodology. First, we undertook a systematic review of RCTs in high-impact journals to describe current outcome reporting trends. We then surveyed patients, carers, researchers, and perioperative clinicians about important outcomes after surgery. Finally, a purposive stakeholder sample participated in a modified Delphi process to develop a core outcome set for perioperative and anaesthesia trials.


      Our systematic review revealed widespread inconsistency in outcome reporting, with variable or absent definitions, levels of detail, and temporal criteria. In the survey, almost all patients, carers, and clinicians rated clinical outcome measures critically important, but clinicians rated patient-centred outcomes less highly than patients and carers. The final core outcome set was: (i) mortality/survival (postoperative mortality, long-term survival); (ii) perioperative complications (major postoperative complications/adverse events; complications/adverse events causing permanent harm); (iii) resource use (length of hospital stay, unplanned readmission within 30 days); (iv) short-term recovery (discharge destination, level of dependence, or both); and (v) longer-term recovery (overall health-related quality of life).


      This core set, incorporating important outcomes for both clinicians and patients, should guide outcome selection in future perioperative medicine or anaesthesia trials. Mapping these alongside standardised endpoint definitions will yield a comprehensive perioperative outcome framework.


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        • Fleming T.R.
        • Powers J.H.
        Biomarkers and surrogate endpoints in clinical trials.
        Stat Med. 2012; 31: 2973-2984
        • Weintraub W.S.
        • Lüscher T.F.
        • Pocock S.
        The perils of surrogate endpoints.
        Eur Heart J. 2015; 36: 2212-2218
        • Myles P.S.
        Perioperative outcomes: are we asking the right questions?.
        Can J Anaesth. 2016; 63: 138-141
        • Shulman M.
        • Myles P.
        Measuring perioperative outcome.
        Curr Opin Anaesthesiol. 2016; 29: 733-738
        • Duncan P.W.
        • Jorgensen H.S.
        • Wade D.T.
        Outcome measures in acute stroke trials: a systematic review and some recommendations to improve practice.
        Stroke. 2000; 31: 1429-1438
        • Bonnot B.
        • Yavchitz A.
        • Mantz J.
        • Paugam-Burtz C.
        • Boutron I.
        Selective primary outcome reporting in high-impact journals of anaesthesia and pain.
        Br J Anaesth. 2016; 117: 542-543
        • Dwan K.
        • Kirkham J.J.
        • Williamson P.R.
        • Gamble C.
        Selective reporting of outcomes in randomised controlled trials in systematic reviews of cystic fibrosis.
        BMJ Open. 2013; 3e002709
        • Bruce J.
        • Krukowski Z.H.
        • Al-Khairy G.
        • Russell E.M.
        • Park K.G.
        Systematic review of the definition and measurement of anastomotic leak after gastrointestinal surgery.
        Br J Surg. 2001; 88: 1157-1168
        • Clarke M.
        Standardising outcomes for clinical trials and systematic reviews.
        Trials. 2007; 8: 39
        • Chalmers I.
        • Glasziou P.
        Avoidable waste in the production and reporting of research evidence.
        Lancet. 2009; 374: 86-89
      1. Patient centred outcome measures. 2015 (Available from:) (accessed 10th June 2016)
        • Kalkman C.J.
        • Kappen T.H.
        Patient-centered endpoints for perioperative outcomes research.
        Anesthesiology. 2015; 122: 481-483
        • Heidegger T.
        • Nuebling M.
        • Saal D.
        • Kreienbühl G.
        Patient-centred outcomes in clinical research: does it really matter?.
        Br J Anaesth. 2008; 100: 1-3
        • Schulz K.F.
        • Altman D.G.
        • Moher D.
        • Group C.
        CONSORT 2010 statement: updated guidelines for reporting parallel group randomised trials.
        BMJ. 2010; 340: c332
        • von Elm E.
        • Altman D.G.
        • Egger M.
        • et al.
        The strengthening the reporting of observational studies in epidemiology (STROBE) statement: guidelines for reporting observational studies.
        Int J Surg. 2014; 12: 1495-1499
        • Gargon E.
        • Gurung B.
        • Medley N.
        • et al.
        Choosing important health outcomes for comparative effectiveness research: a systematic review.
        PLos One. 2014; 9e99111
        • Williamson P.R.
        • Altman D.G.
        • Bagley H.
        • et al.
        The COMET Handbook: version 1.0.
        Trials. 2017; 18: 280
        • McNair A.G.
        • Whistance R.N.
        • Forsythe R.O.
        • et al.
        Core outcomes for colorectal cancer surgery: a consensus study.
        PLoS Med. 2016; 13e1002071
        • Dworkin R.H.
        • Turk D.C.
        • Farrar J.T.
        • et al.
        Core outcome measures for chronic pain clinical trials: IMMPACT recommendations.
        Pain. 2005; 113: 9-19
        • O'Donnell C.M.
        • Black N.
        • McCourt K.C.
        • et al.
        Development of a Core Outcome Set for studies evaluating the effects of anaesthesia on perioperative morbidity and mortality following hip fracture surgery.
        Br J Anaesth. 2019; 122: 120-130
        • Schmitt J.
        • Apfelbacher C.
        • Spuls P.I.
        • et al.
        The Harmonizing Outcome Measures for Eczema (HOME) roadmap: a methodological framework to develop core sets of outcome measurements in dermatology.
        J Invest Dermatol. 2015; 135: 24-30
        • Webster L.
        • Groskreutz D.
        • Grinbergs-Saull A.
        • et al.
        Development of a core outcome set for disease modification trials in mild to moderate dementia: a systematic review, patient and public consultation and consensus recommendations.
        Health Technol Assess. 2017; 21: 1-192
        • Duffy J.
        • Rolph R.
        • Gale C.
        • et al.
        Core outcome sets in women's and newborn health: a systematic review.
        BJOG. 2017; 124: 1481-1489
        • Myles P.S.
        • Grocott M.P.
        • Boney O.
        • Moonesinghe S.R.
        • Group C.-S.
        Standardizing end points in perioperative trials: towards a core and extended outcome set.
        Br J Anaesth. 2016; 116: 586-589
        • Moonesinghe S.R.
        • Jackson A.I.R.
        • Boney O.
        • et al.
        Systematic review and consensus definitions for the Standardised Endpoints in Perioperative Medicine initiative: patient-centred outcomes.
        Br J Anaesth. 2019; 123: 664-670
        • Barnes J.
        • Hunter J.
        • Harris S.
        • et al.
        Systematic review and consensus definitions for the Standardised Endpoints in Perioperative Medicine (StEP) initiative: infection and sepsis.
        Br J Anaesth. 2019; 122: 500-508
        • Beattie W.S.
        • Lalu M.
        • Bocock M.
        • et al.
        Systematic review and consensus definitions for the Standardized Endpoints in Perioperative Medicine (StEP) initiative: cardiovascular outcomes.
        Br J Anaesth. 2021; 126: 56-66
        • Abbott T.E.F.
        • Fowler A.J.
        • Pelosi P.
        • et al.
        A systematic review and consensus definitions for standardised end-points in perioperative medicine: pulmonary complications.
        Br J Anaesth. 2018; 120: 1066-1079
        • Buggy D.J.
        • Freeman J.
        • Johnson M.Z.
        • et al.
        Systematic review and consensus definitions for standardised endpoints in perioperative medicine: postoperative cancer outcomes.
        Br J Anaesth. 2018; 121: 38-44
        • Haller G.
        • Bampoe S.
        • Cook T.
        • et al.
        Systematic review and consensus definitions for the Standardised Endpoints in Perioperative Medicine initiative: clinical indicators.
        Br J Anaesth. 2019; 123: 228-237
        • McIlroy D.R.
        • Bellomo R.
        • Billings F.T.
        • et al.
        Systematic review and consensus definitions for the Standardised Endpoints in Perioperative Medicine (StEP) initiative: renal endpoints.
        Br J Anaesth. 2018; 121: 1013-1024
        • Myles P.S.
        • Boney O.
        • Botti M.
        • et al.
        Systematic review and consensus definitions for the Standardised Endpoints in Perioperative Medicine (StEP) initiative: patient comfort.
        Br J Anaesth. 2018; 120: 705-711
        • WHO
        Health Impact Assessment: glossary of terms used.
        2017 (accessed 2nd April 2021)
        • Velentgas P.
        • Dreyer N.
        • Wu A.
        Outcome definition and measurement.
        in: Developing a Protocol for observational comparative effectiveness research: a user’s guide. Agency for Healthcare Research and Quality (AHRQ), US2013 (Available at:)
        • Kirkham J.J.
        • Davis K.
        • Altman D.G.
        • et al.
        Core outcome set-STAndards for development: the COS-STAD recommendations.
        PLoS Med. 2017; 14e1002447
        • Grocott M.P.W.
        • Myles P.S.
        • Moonesinghe S.R.
        • Boney O.C.
        Core outcome measures in perioperative and anaesthetic care (COMPAC).
        2014 (Available from:) (accessed 2nd April 2021)
        • Dodd S.
        • Clarke M.
        • Becker L.
        • Mavergames C.
        • Fish R.
        • Williamson P.R.
        A taxonomy has been developed for outcomes in medical research to help improve knowledge discovery.
        J Clin Epidemiol. 2018; 96: 84-92
        • De Meyer D.
        • Kottner J.
        • Beele H.
        • et al.
        Delphi procedure in core outcome set development: rating scale and consensus criteria determined outcome selection.
        J Clin Epidemiol. 2019; 111: 23-31
        • Remus A.
        • Smith V.
        • Gutke A.
        • et al.
        A core outcome set for research and clinical practice in women with pelvic girdle pain: PGP-COS.
        PLos One. 2021; 16e0247466
        • Bassi C.
        • Marchegiani G.
        • Dervenis C.
        • et al.
        The 2016 update of the International Study Group (ISGPS) definition and grading of postoperative pancreatic fistula: 11 Years after.
        Surgery. 2017; 161: 584-591
        • Rassweiler J.J.
        • Rassweiler M.C.
        • Michel M.S.
        Classification of complications: is the Clavien-Dindo classification the gold standard?.
        Eur Urol. 2012; 62 (discussion 9–60): 256-258
        • Jammer I.
        • Wickboldt N.
        • Sander M.
        • et al.
        Standards for definitions and use of outcome measures for clinical effectiveness research in perioperative medicine: European Perioperative Clinical Outcome (EPCO) definitions: a statement from the ESA-ESICM joint taskforce on perioperative outcome measures.
        Eur J Anaesthesiol. 2015; 32: 88-105
        • Cho J.Y.
        • Baron T.H.
        • Carr-Locke D.L.
        • et al.
        Proposed standards for reporting outcomes of treating biliary injuries.
        HPB (Oxford). 2018; 20: 370-378
        • Toozs-Hobson P.
        • Bach F.
        • Daly J.O.
        • Klarskov N.
        Minimum standards for reporting outcomes of surgery in urogynaecology.
        Int Urogynecol J. 2020; 32: 1387-1390
        • Burns D.J.P.
        • Arora J.
        • Okunade O.
        • et al.
        International consortium for health outcomes measurement (ICHOM): standardized patient-centered outcomes measurement set for heart failure patients.
        JACC Heart Fail. 2020; 8: 212-222
      2. HTA Stage 1 guidance notes. 2020 (Available from:) (accessed 02 April 2021)
        • Kirkham J.J.
        • Clarke M.
        • Williamson P.R.
        A methodological approach for assessing the uptake of core outcome sets using findings from a review of randomised controlled trials of rheumatoid arthritis.
        BMJ. 2017; 357: j2262
        • Gargon E.
        • Williamson P.R.
        • Young B.
        Improving core outcome set development: qualitative interviews with developers provided pointers to inform guidance.
        J Clin Epidemiol. 2017; 86: 140-152
        • Macefield R.C.
        • Boulind C.E.
        • Blazeby J.M.
        Selecting and measuring optimal outcomes for randomised controlled trials in surgery.
        Langenbecks Arch Surg. 2014; 399: 263-272
        • Williamson P.R.
        • Blazeby J.M.
        • Brookes S.T.
        • Clarke M.
        • Terwee C.B.
        • Young B.
        Controversy and debate series on core outcome sets. Paper 4: debate on paper 1 from the perspective of COMET [core outcome measures in effectiveness trials].
        J Clin Epidemiol. 2020; 125: 222-224