1. EuroSpA Coordinating Center, Copenhagen Center for Arthritis Research (COPECARE), Center for Rheumatology and Spine Diseases, Centre for Head and Orthopaedics, Rigshospitalet, Glostrup
2. DANBIO Registry, Center for Rheumatology and Spine Diseases, Centre for Head and Orthopaedics, Rigshospitalet, Glostrup, Denmark
3. Department of Rheumatology and Inflammation Research, Sahlgrenska Academy at University of Gothenburg, Gothenburg, Sweden
4. Department of Rheumatology, Geneva University Hospital, Geneva, Switzerland
5. Department of Rheumatology, Diakonhjemmet Hospital, Oslo, Norway
6. Institute of Rheumatology and Department of Rheumatology, 1st Faculty of Medicine, Charles University, Prague, Czech Republic
7. Reuma.pt registry and Instituto de Medicina Molecular, Faculdade de Medicina, Universidade de Lisboa, Lisbon, Portugal
8. Research Unit, Spanish Society of Rheumatology, Madrid, Spain
9. ROB-FIN Registry, Helsinki University and Helsinki University Hospital, Helsinki, Finland
10. biorx.si and the Department of Rheumatology, University Medical Centre Ljubljana, Slovenia, Ljubljana
11. Centre for Rheumatology Research, University Hospital and Faculty of Medicine, University of Iceland, Reykjavik, Iceland
12. TURKBIO Registry and Division of Rheumatology, School of Medicine Dokuz Eylul University, Izmir, Turkey
13. Center of Rheumatic Diseases, University of Medicine and Pharmacy, Bucharest, Romania
14. Leitender Arzt der Universitätsklinik für Rheumatologie, Immunologie und Allergologie Inselspital, Bern, Switzerland
15. Rheuma.pt registry, Rheumatology Department—Centro Hospitalar do Baixo Vouga and Ibimed—Institute for Biomedicine, University of Aveiro, Aveiro, Portugal
16. Inflammation Center, Department of Rheumatology, Helsinki University Hospital, Helsinki, Finland
17. University of Iceland, Faculty of Medicine, and Landspitali University Hospital, Reykjavik, Iceland
18. Department of Rheumatology, Aarhus University Hospital, Aarhus, Denmark
19. Amsterdam Rheumatology & immunology Center (ARC), Academic Medical Center, Amsterdam
20. Department of Rheumatology, Amsterdam UMC, VU University Medical Centre Amsterdam, Amsterdam, The Netherlands
21. Epidemiology Group, School of Medicine, Medical Science and Nutrition, University of Aberdeen, Aberdeen, UK
22. GISEA registry, Rheumatology Unit – DETO, University of Bari, Bari, Italy
23. Zitelabs Aps, Copenhagen
24. Department of Clinical Medicine, University of Copenhagen, Copenhagen, Denmark