1. Department of Rheumatology, St. Elisabeth-Hospital Meerbusch-Lank, Hauptstr. 74-76, 40668 Meerbusch, Germany
2. Department of Rheumatology and Hiller Research Unit, University Hospital Düsseldorf, Medical Faculty, Heinrich Heine University Düsseldorf, Moorenstr. 5, 40225 Düsseldorf, Germany
3. Rheumazentrum Ruhrgebiet, Ruhr University Bochum, Claudiusstrasse 45, 44649 Herne, Germany
4. Department of Rheumatology, Krankenhaus Porz am Rhein, 51149 Cologne, Germany
5. Faculty of Health, School of Medicine, Witten/Herdecke University, 58455 Witten, Germany
6. Midaia GmbH, 69123 Heidelberg, Germany
7. Department of Internal Medicine 3, Bogomolets National Medical University, 01601 Kyiv, Ukraine
8. Medical Biometry and Epidemiology, University of Witten/Herdecke, 58448 Witten, Germany