A core outcome set for post-COVID-19 condition in adults for use in clinical practice and research: an international Delphi consensus study

Abstract

Health consequences that persist beyond the acute infection phase of COVID-19, termed post-COVID-19 condition (also commonly known as long COVID), vary widely and represent a growing global health challenge. Research on post-COVID-19 condition is expanding but, at present, no agreement exists on the health outcomes that should be measured in people living with the condition. To address this gap, we conducted an international consensus study, which included a comprehensive literature review and classification of outcomes for post-COVID-19 condition that informed a two-round online modified Delphi process followed by an online consensus meeting to finalise the core outcome set (COS). 1535 participants from 71 countries were involved, with 1148 individuals participating in both Delphi rounds. Eleven outcomes achieved consensus for inclusion in the final COS: fatigue; pain; post-exertion symptoms; work or occupational and study changes; survival; and functioning, symptoms, and conditions for each of cardiovascular, respiratory, nervous system, cognitive, mental health, and physical outcomes. Recovery was included a priori because it was a relevant outcome that was part of a previously published COS on COVID-19. The next step in this COS development exercise will be to establish the instruments that are most appropriate to measure these core outcomes. This international consensus-based COS should provide a framework for standardised assessment of adults with post-COVID-19 condition, aimed at facilitating clinical care and research worldwide.

Figure

Overview of the COS development process For the Delphi survey, all outcomes from the first round were included in the second round. COMET=Core Outcome Measures in Effectiveness Trials. COS=core outcome set. *Outcomes were classified using COMET taxonomy. †Outcomes were classified into survival, physiological or clinical, life impact, and resource use outcomes. ‡Participants were classified into three stakeholder groups: people with post-COVID-19 condition and family members or caregivers, health-care professionals and researchers with post-COVID-19 condition, and health-care professionals and researchers without post-COVID-19 condition. §Participants were classified into two stakeholder groups: people with post-COVID-19 condition and family members or caregivers, and health-care professionals and researchers without post-COVID-19 condition. ¶Additional outcome was part of a previously published COS for COVID-19.