1. Rheumatology Clinic, Department of Medical and Biological Sciences, University Hospital Santa Maria della Misericordia, Udine
2. Rheumatology Unit, Azienda Sanitaria di Firenze, S. Giovanni di Dio Hospital, Florence
3. Rheumatology Unit, L. Sacco University Hospital
4. Epidemiology Unit of the Italian Society for Rheumatology (SIR), Milan
5. Department of Medical Sciences, Section of Rheumatology, University of Ferrara, Ferrara
6. Dipartimento di Scienze Cliniche e Biologiche, Università degli Studi di Torino, Turin
7. Division of Rheumatology, IRCCS Policlinico San Matteo Foundation, University of Pavia, Pavia, Italy