1. Department of Medical Sciences, Rheumatology Unit, University of Ferrara and Azienda Ospedaliero-Universitaria S. Anna, Cona (Ferrara), Italy
2. Rheumatology Unit, University Clinic and Azienda Ospedaliero-Universitaria of Cagliari, Cagliari, Italy
3. Rheumatology Unit, Maggiore Hospital AUSL, Bologna, Italy
4. Internal Medicine, State Hospital, Borgo Maggiore, Republic of San Marino
5. Epidemiology Unit, Italian Society for Rheumatology, Milan, Italy
6. Rheumatology, Clinical Immunology and Allergy Unit, University of Crete, Heraklion, Greece