A Core Outcome Measurement Set (COMS) for Research and Clinical Practice in Post COVID-19 Condition (Long COVID) in Adults: An International Delphi Consensus Study

Abstract

Background: Agreement is lacking regarding which instruments should be used for measurement of a recently-agreed core outcome set (COS) for clinical practice and research in post COVID-19 condition, also known as Long COVID.

Methods: A rigorous multi-step consensus study was conducted, including a comprehensive literature review informing a three-round online modified Delphi process followed by an online consensus meeting to finalise measurement instruments for this COS, thereby developing a Core Outcome Measurement Set (COMS). 594 participants from 58 countries spanning six continents, participated in the consensus process.

Findings: Consensus was reached for including the ‘modified MRC Dyspnea Scale’ for measuring the ‘Respiratory functioning, symptoms, and conditions’ outcome in the COMS. Two outcome measures from the acute COVID-19 COMS were included in this post COVID-19 conditionCOMS, namely ‘Time until death’ (for the Survival outcome) and ‘Recovery Scale for COVID-19’ (for the Recovery outcome). Consensus, based on predefined criteria, was not reached for the other 9 outcomes of the COS. However, based on the study results, suggested measurement instruments are provided for ‘Fatigue’, ‘Post-exertion symptoms’; ‘Pain’, ‘Physical function’, ‘Work/occupational and study changes’ and for ‘Cardiovascular’, ‘Nervous system’, ‘Cognition’ and ‘Mental’ functioning, symptoms and conditions.

Interpetation: This international COMS provides a framework for assessing post COVID-19 condition in global clinical research and practice settings. Further evaluation is warranted as new data emerges on the performance of measurement instruments for the COS for this new clinical condition.

Note:
Funding Declaration: DM reports receipt of grants from the British Embassy in Moscow, UK National Institute for Health Research (NIHR) and Russian Foundation for Basic Research. TN reports funding from the UK National Institute for Health and Social Care Research (NIHR). PRW reports that she received funding from the UK National Institute for Health Research (NIHR).

Conflict of Interests: DM reports receipt of grants from the British Embassy in Moscow, UK National Institute for Health Research (NIHR) and Russian Foundation for Basic Research. He is also a Co-Chair of International Severe Acute Respiratory and Emerging Infection Consortium (ISARIC) Global Paediatric Long COVID Working Group, member of ISARIC working group on long-term follow-up in adults and co-lead of the PC-COS project. TN reports funding from the UK National Institute for Health and Social Care Research (NIHR). SLG is the COMET Initiative project coordinator. NH reports payment and honoraria for lectures and presentations from Lancaster University. PRW reports that she received funding from the UK National Institute for Health Research (NIHR) and is also a chair of the Core Outcome Measures in Effectiveness Trials (COMET) Management Group. SLG is the COMET project coordinator. Other authors declare that they have no competing interests.

Ethics Approval: The study protocol was developed a priori, published on the study website(7) and approved, along with all study materials, by the UK Health Research Authority and by the South West Cornwall & Plymouth Research Ethics Committee (REC number 21/SW/0109).

Keywords: covid, outcomes, outcome measures, long covid, post COVID-19 condition, post acute sequelae COVID-19, core outcome set