[1] Univ Hosp Bonn, Bonn, Germany
[2] Med Univ Graz, Dept Rheumatol, Graz, Austria
[3] Teaching Hosp Paracelsius Med Univ, Hosp Bruneck ASAA SABES, Dept Rheumatol, Brunico, Italy
[4] Univ Hosp Bonn, Dept Oncol Hematol Rheumatol & Clin Immunol, Clin Internal Med 3, Bonn, Germany
[5] Univ Bonn, Fac Med, Inst Med Biometry Informat & Epidemiol, Bonn, Germany