1. Rheumatology Unit, Department of Medical Sciences, University of Ferrara and Azienda Ospedaliero-Universitaria S. Anna, Cona, Ferrara, Italy.
2. University of Pavia, Istituti Clinici Scientifici Maugeri IRCCS Pavia, Italy.
3. Rheumatology Unit, Department of Medicine, University of Verona, Policlinico G. B. Rossi, Verona, and Division of Rheumatology, University of Padova, Italy.
4. Rheumatology Division, Multispecialist Medical Department, ASST Grande Ospedale Metropolitano Niguarda, Milan, Italy.
5. Rheumatology Unit, Department of Medical Sciences, University of Ferrara and Azienda Ospedaliero-Universitaria S. Anna, Cona, Ferrara, and Epidemiology Unit, Italian Society for Rheumatology, Milan, Italy. scrcll@unife.it