1. Rheumatology Unit, University of Modena and Reggio Emilia, Modena, Italy
2. Rheumatology Unit, Department of Clinical and Experimental Medicine, University of Padua, Padua, Italy
3. Department of Clinical and Experimental Medicine, Rheumatology Unit, Second University of Naples, Naples, Italy
4. Division of Rheumatology, Catholic University of the Sacred Heart, Rome, Italy
5. Department of Internal Medicine, Rheumatology Unit, Policlinico S. Orsola Malpighi, Bologna, Italy
6. Rheumatology Unit, Department of Clinical & Experimental Medicine, University of Perugia, Perugia, Italy
7. Rheumatology Unit, Department of Molecular Pathology and Innovative Therapies, Università Politecnica delle Marche, Ancona, Italy
8. Internal Medicine Unit - Civitanova Marche Hospital, Italy
9. DiMIMP, Rheumatology Unit, University of Bari, Bari, Italy
10. Department of Clinical and Experimental Medicine-Rheumatology Unit, Sant'Anna Hospital, University of Ferrara, Ferrara, Italy
11. Unit of Statistics in Medicine, Department of Public Health, Clinical and Diagnostic Medicine, University of Modena and Reggio Emilia, Modena, Italy
12. Department of Internal Medicine, Pugliese-Ciaccio Hospital, Catanzaro, Italy