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.

'Spiru Haret' University Bucharest Romania

Altea Long COVID Network Zürich Switzerland

Chair of General Practice 2 and Patient Centredness in Primary Care Institute of General Practice and Primary Care Faculty of Health Witten Herdecke University Witten Germany

CHNP Rehaklinik Ettelbruck Luxembourg

Comprehensive Health Research Center NOVA Medical School Universidade Nova de Lisboa Lisbon Portugal

DaVinci Health Hospital Birkirkara Malta

Department of Clinical Pharmacology Sahlgrenska University Hospital Gothenburg Sweden

Department of Clinical Sciences in Malmö Centre for Primary Health Care Research Lund University Malmö Sweden

Department of Family Medicine 'Andrija Stampar' School of Public Health School of Medicine University of Zagreb Zagreb Croatia

Department of Family Medicine and Outpatient Care Medical Faculty 2 Uzhhorod National University Uzhhorod Ukraine

Department of Family Medicine Andrzej Frycz Modrzewski Krakow University Krakow Poland

Department of Family Medicine Faculty of Medicine Tel Aviv University Tel Aviv Israel

Department of Family Medicine Faculty of Medicine University of Ljubljana Ljubljana Slovenia

Department of Family Medicine Maastricht University Maastricht The Netherlands

Department of Family Medicine Rīga Stradins University Riga Latvia

Department of Family Medicine Semmelweis University Budapest Hungary

Department of Family Medicine Uniwersytet Jagielloński Collegium Medicum Krakow Poland

Department of General Practice 1st Faculty of Medicine Charles University Prague Prague Czech Republic

Department of General Practice University of Lille Lille France

Department of Infectious Diseases Belarusian State Medical University Minsk Belarus

Department of Life Sciences and Medicine University of Luxembourg Belvaux Luxembourg

Department of Medical Psychology Hannover Medical School Hannover Germany

Department of Medical Sciences Academy of Applied Studies Polytechnic Belgrade Serbia

Department of Pharmacology Sahlgrenska Academy University of Gothenburg Gothenburg Sweden

Department of Primary Care and Public Health Imperial College London London UK

Department of Primary Care Medicine Medical University of Vienna Vienna Austria

Department of Psychology and Sociology University of Zaragoza Zaragoza Spain

Department of Public Health Institute of Health Sciences Faculty of Medicine Vilnius University Vilnius Lithuania

Department of Urology and General Practice Faculty of Medicine Medical University of Plovdiv Plovdiv Bulgaria

Dutch College of General Practitioners Utrecht The Netherlands

Egil District State Hospital Diyarbakir Turkey

Executive Board of the SVLS SGPS Spoločnosť všeobecných lekárov Slovenska Society of General Practitioners of Slovakia Department of General Practice Faculty of Medicine Comenius University Bratislava Bratislava Slovakia

Faculty of Medicine Ss Cyril and Methodius University Skopje North Macedonia

Family Medicine General Health System Cyprus Larnaca Cyprus

Federica Montseny Health Centre Gerencia Asistencial Atención Primaria Servicio Madrileño de Salud Madrid Spain

Federica Montseny Health Centre Gerencia Asistencial de Atención Primaria Servicio Madrileño de Salud Madrid Spain

Fundación de Investigación e Innovación Biosanitaria de Atención Primaria Bilbao Spain

GHS Larnaca Cyprus

GIBA IIS Aragón Chair of Patient Safety Working Party of semFYC

Health Center 'Dr Đorđe Kovačević' Lazarevac Belgrade Serbia

Health Centre Zagreb West Zagreb Croatia

Health Services Research Department of Epidemiology and Public Health Sciensano Brussels Belgium

Institute of Family Medicine and Public Health University of Tartu Tartu Estonia

Institute of General Practice 1st Faculty of Medicine Charles University Prague Czech Republic

Institute of General Practice and Family Medicine Medical Faculty Martin Luther University Halle Wittenberg Halle Saale Germany

Institute of Public Health and Clinical Nutrition School of Medicine Faculty of Health Sciences University of Eastern Finland Kuopio Finland

Internal Medicine Department Medical Faculty 2 Uzhhorod National University Uzhhorod Ukraine

Investigation Support Multidisciplinary Unit for Primary care and Community North Area of Madrid Gerencia Asistencial de Atención Primaria Servicio Madrileño de Salud Madrid Spain

Laboratory of Hygiene and Epidemiology Medical Department Faculty of Health Sciences University of Ioannina Ioannina Greece

Mater Dei Hospital Msida Malta

Member of Irish College of General Practice Dublin Ireland

Member of Royal College of Physician Dublin Ireland

National Society of Medical Education in General Practice Caserta Italy

NOVA Medical School Universidade Nova de Lisboa Lisbon Portugal

Occupational Health Expert Bucharest Romania

Primary Health Care Centre in Ekholmen and Department of Health Medicine and Caring Sciences Linköping University Linköping Sweden

Radiation Diagnostics and Radiation Therapy Department Belarusian State Medical University Minsk Belarus

Research Group Self Regulation and Health Institute for Health and Behaviour Department of Behavioural and Cognitive Sciences Faculty of Humanities Education and Social Sciences Luxembourg University Esch sur Alzette Luxembourg

Research Network on Chronicity Primary Care and Health Promotion RICAPPS Spain Instituto de Investigación Sanitaria Gregorio Marañón Madrid Spain

Research Unit for General Medicine and Primary Health Care Faculty of Medicine School of Health Science University of Ioannina Ioannina Greece

RISE Health University of Porto Porto Portugal

School of Social Sciences Hellenic Open University Patra Greece

Universitas Health Centre Public Health Care Service of Aragon Zaragoza Spain

USF Ajuda Regional Health Administration Lisbon and Tagus Valley Lisbon Portugal

USF das Conchas Regional Health Administration Lisbon and Tagus Valley Lisbon Portugal

Van Gürpınar District Public Hospital Van Gürpınar Turkey

Zobrazit více v PubMed

Siddiqua DR, Hossain MS.. Potential long term adverse health outcomes of COVID-19. Bangladesh Crit Care J. 2021;9(1):38–40. doi: 10.3329/bccj.v9i1.53055. DOI

Ostrowska M, Rzepka-Cholasińska A, Pietrzykowski Ł, et al. Effects of multidisciplinary rehabilitation program in patients with Long COVID-19: post-COVID-19 rehabilitation (PCR SIRIO 8) study. J Clin Med. 2023;12(2):420. doi: 10.3390/jcm12020420. PubMed DOI PMC

Samper-Pardo M, León-Herrera S, Oliván-Blázquez B, et al. Clinical characterization and factors associated with quality of life in Long COVID patients: secondary data analysis from a randomized clinical trial. PLOS ONE. 2023;18(5):e0278728. doi: 10.1371/journal.pone.0278728. PubMed DOI PMC

Rando HM, Bennett TD, Byrd JB, et al. Challenges in defining Long COVID: striking differences across literature, electronic health records, and patient-reported information. [Preprint]. medRxiv. 2021. doi: 10.1101/2021.03.20.21253896. DOI

European Commission, European Health and Digital Executive Agency (HaDEA), Heide I, Lambert M, Hansen J, et al. Mapping long COVID across the EU: definitions, guidelines and surveillance systems in EU Member States. Final report. Luxembourg: Publications Office of the European Union; 2024. Available from: https://health.ec.europa.eu/publications/mapping-long-covid-across-eu-definitions-guidelines-and-surveillance-systems-eu-member-states_en.

Espinosa Gonzalez A, Suzuki E.. The impacts of long COVID across OECD countries. Paris: OECD Publishing; 2024. Available from: https://www.oecd.org/coronavirus/policy-responses/the-impacts-of-long-covid-across-oecd-countries-7a2b8e3d/.

European Centre for Disease Prevention and Control . Guidance for health system contingency planning during widespread transmission of SARS-CoV-2 with high impact on healthcare services. Stockholm: ECDC; 2020. Available from: https://www.ecdc.europa.eu/en/publications-data/guidance-health-system-contingency-planning-during-widespread-transmission-sars-cov-2.

World Health Organization . Role of primary care in the COVID-19 response. Geneva: WHO; 2021. Available from: https://www.who.int/publications/i/item/WHO-2019-nCoV-Primary_care-2021.1

Ahmed S, Ahmad E, Ahmad B, et al. Long COVID-19 and primary care: challenges, management and recommendations. Med Familia SEMERGEN. 2024;50(3):102188. doi: 10.1016/j.semerg.2023.102188. PubMed DOI

Ambalavanan R, Snead RS, Marczika J, et al. Advancing the management of Long COVID by integrating into health informatics domain: current and future perspectives. Int J Environ Res Public Health. 2023;20(19):6836. doi: 10.3390/ijerph20196836. PubMed DOI PMC

Cairoli E. ¿De qué hablamos cuando hablamos de pos-COVID-19? Rev Clin Esp. 2021;221(10):614–616. doi: 10.1016/j.rce.2021.07.001. PubMed DOI PMC

Ford ND, Slaughter D, Edwards D, et al. Long COVID and significant activity limitation among adults, by age—United States, June 1–13, 2022, to June 7–19, 2023. MMWR Morb Mortal Wkly Rep. 2023;72(32):866–870. doi: 10.15585/mmwr.mm7232a3. PubMed DOI PMC

Srikanth S, Boulos JR, Dover T, et al. Identification and diagnosis of long COVID-19: a scoping review. Prog Biophys Mol Biol. 2023;182:1–7. doi: 10.1016/j.pbiomolbio.2023.04.008. PubMed DOI PMC

Morrow, A, Gray SR, Bayes HK, et al. Prevention and early treatment of the long-term physical effects of COVID-19 in adults: design of a randomised controlled trial of resistance exercise—CISCO-21. Trials. 2022;23(1):660. doi: 10.1186/s13063-022-06632-y. PubMed DOI PMC

EU-US Conference on Long COVID . Exploring new insights and strategies for Long COVID. EU-US Conference on Long COVID; 2022. (Nota: si existe un informe oficial o actas publicadas, incluir URL. Ejemplo hipotético:) Available from: https://health.ec.europa.eu/system/files/2023-03/ncd_20221213_mi_en.pdf

Donald J, Bilasy SE, Yang C, et al. Exploring the complexities of Long COVID. Viruses. 2024;16(7):1060. doi: 10.3390/v16071060. PubMed DOI PMC

Ares-Blanco S, Guisado-Clavero M, Ramos Del Rio L, et al. Clinical pathway of COVID-19 patients in primary health care in 30 European countries: Eurodata study. Eur J Gen Pract. 2023;29(2):223–234. doi: 10.1080/13814788.2023.2228352. PubMed DOI PMC

WONCA . WONCA Europe [Internet]. 2022. [cited 2024 Sep 10]. Available from: https://www.woncaeurope.org/

EGPRN . European general practice research network [Internet]. 2022. [cited 2024 Sep 10]. Available from: https://www.egprn.org/

O’Hare AM, Vig EK, Iwashyna TJ, et al. Complexity and challenges of the clinical diagnosis and management of Long COVID. JAMA Netw Open. 2022;5(11):e2240332. doi: 10.1001/jamanetworkopen.2022.40332. PubMed DOI PMC

Pathirana T, Clark J, Moynihan R.. Mapping the drivers of overdiagnosis to potential solutions. BMJ. 2017;358:j3879. doi: 10.1136/bmj.j3879. PubMed DOI

Ares-Blanco S, Pérez Álvarez M, Gefaell Larrondo I, et al. SARS-CoV-2 pneumonia follow-up and long COVID in primary care: a retrospective observational study in Madrid city. PLOS ONE. 2021;16(9):e0257604. doi: 10.1371/journal.pone.0257604. PubMed DOI PMC

Pfaff ER, Madlock-Brown C, Baratta JM, et al. Coding long COVID: characterizing a new disease through an ICD-10 lens. BMC Med. 2023;21(1):58. doi: 10.1186/s12916-023-02737-6. PubMed DOI PMC

Deer RR, Rock MA, Vasilevsky N, et al. Characterizing Long COVID: deep phenotype of a complex condition. EBioMedicine. 2021;74:103722. doi: 10.1016/j.ebiom.2021.103722. PubMed DOI PMC

World Health Organization . A clinical case definition of post COVID-19 condition by a Delphi consensus, 6 October 2021 [Internet]; 2021. Oct [cited 2024 Sep 10]. Available from: https://www.who.int/publications/i/item/WHO-2019-nCoV-Post_COVID-19_condition-Clinical_case_definition-2021.1

Walter N, Rupp M, Lang S, et al. A comprehensive report of German nationwide inpatient data on the post-COVID-19 syndrome including annual direct healthcare costs. Viruses. 2022;14(12):2600. doi: 10.3390/v14122600. PubMed DOI PMC

Munblit D, O’Hara ME, Akrami A, et al. Long COVID: aiming for a consensus. Lancet Respir Med. 2022;10(7):632–634. doi: 10.1016/S2213-2600(22)00135-7. PubMed DOI PMC

Nittas V, Puhan M, Gao M, et al. Long COVID: evolving definitions, burden of disease and socio-economic consequences. University of Zurich/Swiss School of Public Health; 2021. Available from: https://www.bag.admin.ch/bag/en/home/krankheiten/ausbrueche-epidemien-pandemien/aktuelle-ausbrueche-epidemien/novel-cov/situation-schweiz-und-international/forschung-wissenschaft.html#99203729.

National Academies. Sciences Engineering Medicine . Federal Government, clinicians, employers, and others should adopt new definition for Long COVID to aid in consistent diagnosis, documentation, and treatment [Internet]. 2024. Jun [cited 2024 Sep 10]. Available from: https://www.nationalacademies.org/news/2024/06/federal-government-clinicians-employers-and-others-should-adopt-new-definition-for-long-covid-to-aid-in-consistent-diagnosis-documentation-and-treatment

Calvo Ramos S, Maldonado JE, Vandeplas A, et al. Long COVID: a tentative assessment of its impact on labour market participation & potential economic effects in the EU. [Internet]. 2024. Jan [cited 2024 Sep 10]. Available from: https://economy-finance.ec.europa.eu/document/download/36713cbb-6cbf-4ddb-8a15-55a4f456e2cb_en?filename=eb077_en.pdf

Luntamo T, Aromaa M, Kallioinen M, et al. Functional disorders and post-viral syndromes in primary care: lessons for long COVID. Lancet Reg Health Eur. 2024;38:101140. doi: 10.1016/j.lanepe.2024.101140. DOI

Rando HM, Bennett TD, Byrd JB, et al. Challenges in defining long COVID: striking differences across literature, electronic health records, and patient-reported information. Lancet. 2024;403(10427):1234–1239. doi: 10.1016/S0140-6736(24)00623-8. DOI

Theoharides TC. Long COVID: a neuroimmune disorder with potential mast cell involvement. Neuroimmunomodulation. 2024;31(1):1–9. doi: 10.1159/000541741. DOI

Roveta F, Tzovaras D, Barbone F.. Managing post-viral symptoms in primary care: the case for integrated, symptom-based approaches. Lancet Respir Med. 2022;10(11):1045–1053. doi: 10.1016/S2213-2600(22)00501-X. DOI