1. Rheumatology Center Rhineland-Palatinate, Kaiser-Wilhelm-Str. 9-11, 55543 Bad Kreuznach, Germany
2. Department of Internal Medicine I, Division of Rheumatology and Clinical Immunology, University Medical Center, Johannes Gutenberg University, 55131 Mainz, Germany
3. Department of Internal Medicine, Helios Clinic, 47805 Krefeld, Germany
4. Department of Rheumatology, University and IRCCS Policlinico S. Matteo Foundation Pavia, 27100 Pavia, Italy
5. Rheumazentrum Ruhrgebiet Herne, Ruhr-University Bochum, 44649 Herne, Germany
6. Department of Internal Medicine and Rheumatology, School of Medicine, University of Crete, 71500 Heraklion, Greece
7. Department of Internal Medicine D, Section of Rheumatology and Clinical Immunology, University Hospital Munster, 48149 Munster, Germany