Title: Long COVID Core Outcome Set (LC-COS) project
Funder: Department of Health and Social Care

Abstract: This project will develop a Core Outcome Set (COS) for Long COVID for use in clinical trials, other research and clinical services. We have brought together a core group of national and international experts across all relevant clinical and research areas to work together with Long COVID patient groups, including patient researchers, to co-design a project with collaboration from key organisations and existing major relevant studies such as the World Health Organisation (WHO), the International Severe Acute Respiratory and emerging Infection Consortium (ISARIC) and the NIHR funded TLC and HEAL-COVID studies. The Core Outcome Measures in Effectiveness Trials (COMET) framework methodology has been adopted and the project registered on the COMET database.1 The 1st phase of achieving consensus on what core outcomes should be measured is underway and will be completed in July/August 2021. This will culminate in an international Delphi study of over 200 expert researchers and clinicians from over 25 countries, over 2,000 Long COVID patients (recruited from both online groups and directly from clinical services globally) and approximately 50 other key stakeholders such as research and clinical service funders. The 2nd phase - how to measure these core outcomes - is proposed in this application and is based around a second Delphi study with the same participants, informed by the consensus core outcomes identified in Phase 1. We will firstly rapidly review the known measurement instruments or definitions (hereafter 'measurement instruments') for these outcomes as well as the psychometric and other key properties of these measures. We will then develop measure cards that clearly and concisely explain potential outcome measurement instruments to the participants to inform their preferences in the Delphi study. A COS and recommended measures for use in all Long COVID studies and/or identification of gaps where new instruments need to be developed.

Lay abstract: This study aims to reach an agreement amongst researchers, clinicians, patients and people from other key perspectives ( stakeholders ) on how to measure improvement in Long COVID. This is particularly important for studies of whether treatments work ( treatment trials ) where using different measurement methods makes it difficult to compare results from different studies. It is also important that clinicians treating Long COVID measure aspects of disorders that matter most to patients, health professionals and others (for example those funding services). Researchers aim for such agreement by developing Core Outcome Sets (known as a COS ) which specify the core (i.e., key things) that should be measured in all patients. The ideal way to reach agreement on &ldquo;what to measure?&rdquo;, and &ldquo;how to measure?&rdquo;, has been defined by the COMET (Core Outcome Measures in Effectiveness Trials) framework which we will use to assemble global experts from relevant areas of research and medicine to work with patients and other stakeholders to compare and then reach agreement. The initial work on &ldquo;what to measure?&rdquo; is already underway and will be completed by the start of this study. This study aims to get agreement on &ldquo;how to measure?&rdquo; these core outcomes in terms of what are the ideal questionnaires or other assessment methods. Once agreed the COS will be widely disseminated by publications in the peer-reviewed scientific journals and via network members as well as the leading national and international organisations. We will ensure that mainstream and social media are informed of the COS increasing awareness in healthcare professionals, researchers, Long COVID patients and the public. Our team has established strong links and is working with key national and international groups (e.g. UK research and clinician networks and the World Health Organisation) to maximise the impact of this work improving how we measure Long COVID.

Research activity codes: 2.5 RESEARCH DESIGN AND METHODOLOGIES (AETIOLOGY)
Health categories: INFECTION