[1] Univ Paris 06, Sorbonne univ, Inst Pierre Louis Epidemiol & Sante Publ, F-75013 Paris, France
[2] Grp Hosp Pitie Salpetriere, AP HP, Dept Rheumatol, 47-83 Blvd Hop, F-75634 Paris, France
[3] Paris Descartes Univ, Dept Rheumatol, Cochin Hosp & Epidemiol, F-75014 Paris, France
[4] Sorbonne Paris Cite Res Ctr, INSERM, Biostat unit, F-75004 Paris, France
[5] Univ Med & Pharm Carol Davila, Sf Maria Hosp, Res Ctr Rheumat Dis, Bucharest 011172, Romania
[6] Rheumazentrum Ruhrgebiet, D-44649 Herne, Germany
[7] Ruhr Univ Bochum, D-44801 Bochum, Germany
[8] Hosp Clin Barcelona, Dept Rheumatol, Arthrit Unit, E-08036 Barcelona, Spain
[9] IDIBAPS, Barcelona 08036, Spain
[10] Univ Hosp Leuven, Dept Rheumatol, B-1348 Leuven, Belgium
[11] People Arthrit Rheumatism Europe PARE, CH-8000 Zurich, Switzerland
[12] Oestfold Univ Coll, Fac Hlth & Social Studies, NO-1757 Halden, Norway
[13] Reg Res Support Oslo, Univ Hosp Postbox 4956, NO-0424 Oslo, Norway
[14] Univ Leeds, Inst Rheumat & Musculoskeletal Med, Leeds LS2 9JT, W Yorkshire, England
[15] Ankara Univ, Div Rheumatol, Fac Med, TR-06560 Ankara, Turkey
[16] Assoc Difesa Psoriasici ADIPSO, Pan European Psoriasis Patients Org Forum PEPsoPO, I-00193 Rome, Italy
[17] Natl Inst Rheumatism & Physiotherapy, Rd Rheumatol Dept, H-1051 Budapest, Hungary
[18] East Tallinn Cent Hosp, Dept Rheumatol, EE-10001 Tallinn, Estonia
[19] Univ Roma La Sapienza, Dipartimento Med Interna & Special Med, Reumatol, I-00185 Rome, Italy
[20] Med Univ Vienna, Dept Med 3, Div Rheumatol, Dept Med 2,Hietzing Hosp, A-1130 Vienna, Austria
[21] Univ Appl Sci FH Campus Wien, Div Hlth Assisting Engn, Dept Hlth, A-1140 Vienna, Austria
[22] St Vincents Univ Hosp, Dublin Acad Med Ctr, Elm Pk, Dublin 4, Ireland
[23] Diakonhjemmet Hosp, Dept Rheumatol, N-0370 Oslo, Norway