Towards consensus: The need for standardised definitions in Long (post) COVID care in 34 European countries.

Background: The COVID-19 pandemic has significantly impacted global healthcare systems, leading to challenges in managing Long COVID. Variations in definitions and diagnostic criteria across Europe hinder recognition and treatment efforts. This study aims to analyse and compare the definitions of Long COVID used in 34 European countries.

Methods: A retrospective descriptive study was conducted involving key informants from 34 European countries, utilising an online questionnaire to gather data on Long COVID definitions. Quantitative and qualitative analyses were employed to assess the variability of definitions and challenges in managing Long COVID.

Results: The study found significant variation in Long COVID definitions among the participating countries; the most frequent definition was the other definition (n: 17, 50.0%), followed by the World Health Organisation's definition (n: 16, 47.0%) and the CDC definition (n: 11, 32.3%). Half of the countries reported using multiple definitions simultaneously, indicating a lack of standardisation. Qualitative analyses highlighted challenges such as difficulties in standardising terminology, variability in clinical criteria, and issues with implementing diagnostic codes.

Conclusion: The findings underscore the need for a unified, yet adaptable, definition of Long COVID. Such a definition would support general practitioners (GPs) by simplifying diagnostic processes, improving continuity of care, and facilitating equitable patient access to multidisciplinary resources. The current lack of consensus complicates patient care, data collection, and resource allocation, impacting health policy development. Future efforts should focus on achieving agreement on definitions to ensure equitable treatment and effective healthcare responses to Long COVID.