1. Copenhagen University Hospital at Glostrup; Copenhagen Denmark
2. Hospital General Universitario Gregorio Marañón; Madrid Spain
3. Sapienza Università di Roma; Rome Italy
4. National Institute of Rheumatology and Physiotherapy; Budapest Hungary
5. University of Leeds; Leeds UK
6. Université Versailles-Saint Quentin, Paris, and AP-HP, Hôpital Ambroise Paré; Boulogne-Billancourt France
7. Istanbul Medeniyet University, Goztepe Training and Research Hospital; Istanbul Turkey
8. Military Medical Institute; Warsaw Poland
9. Diakonhjemmet Hospital; Oslo Norway
10. MC Groep; Lelystad The Netherlands
11. Università Politecnica delle Marche; Jesi, Ancona Italy
12. Université Paris 6-Pierre et Marie Curie, Hôpital La Pitié Salpetrière, AP-HP; Paris France
13. University of Vienna; Vienna Austria
14. National Institute of Rehabilitation; Mexico City Mexico
15. Immanuel Krankenhaus Berlin, Medical Centre for Rheumatology; Berlin-Buch, Berlin Germany