[1] Rigshospitalet, Ctr Head & Orthoped, Ctr Rheumatol & Spine Dis, Copenhagen Ctr Arthrit Res COPECARE, Valdemar Hansens Vej 17, DK-2600 Glostrup, Denmark
[2] Sorlandet Hosp, Res Unit, N-4604 Kristiansand, Norway
[3] Diakonhjemmet Hosp, Ctr Treatment Rheumat & Musculoskeletal Dis REMEDY, Oslo, Norway
[4] Rigshospitalet, DANBIO Registry, Glostrup, Denmark
[5] Univ Copenhagen, Dept Clin Med, Copenhagen, Denmark
[6] Landspitali Univ Hosp, Ctr Rheumatol Res, Reykjavik, Iceland
[7] Univ Iceland, Fac Med, Reykjavik, Iceland
[8] Landspitali Univ Hosp, Dept Rheumatol, Reykjavik, Iceland
[9] Inst Rheumatol, Prague, Czech Republic
[10] Charles Univ Prague, Fac Med 1, Dept Rheumatol, Prague, Czech Republic
[11] Aarhus Univ Hosp, Dept Rheumatol, Aarhus, Denmark
[12] Aarhus Univ, Dept Clin Med, Aarhus, Denmark
[13] Univ Med Ctr Ljubljana, Dept Rheumatol, Ljubljana, Slovenia
[14] Univ Ljubljana, Fac Med, Ljubljana, Slovenia
[15] Geneva Univ Hosp, Dept Rheumatol, Geneva, Switzerland
[16] Inst Biostat & Analyses Ltd, Brno, Czech Republic
[17] Univ Aberdeen, Aberdeen Ctr Arthrit & Musculoskeletal Hlth, Epidemiol Grp, Aberdeen, Scotland
[18] Univ Bari, Rheumatol Unit, DiMePReJ, Bari, Italy
[19] ASST G Pini CTO, Dept Rheumatol & Med Sci, Milan, Italy
[20] Univ Milan, Milan, Italy
[21] East Tallinn Cent Hosp, Dept Rheumatol, Tallinn, Estonia
[22] Natl Inst Hlth Dev, Tallinn, Estonia
[23] Karolinska Inst, Dept Med Solna, Clin Epidemiol Div, Stockholm, Sweden
[24] Lund Univ, Skane Univ Hosp, Dept Clin Sci Lund, Rheumatol, Lund, Sweden
[25] Inland Norway Univ Appl Sci, Publ Hlth Sect, Elverum, Norway
[26] Hosp Gen Univ Gregorio Maranon, Dept Rheumatol, Madrid, Spain
[27] Univ Complutense Madrid, Fac Med, Madrid, Spain
[28] Spanish Soc Rheumatol, Res Unit, Madrid, Spain
[29] Univ Amsterdam, Amsterdam UMC, Dept Rheumatol & Clin Immunol, Amsterdam, Netherlands
[30] Amsterdam Inst Infect & Immun, Dept Expt Immunol, Amsterdam, Netherlands
[31] Reade & Amsterdam UMC, Amsterdam Rheumatol immunol Ctr, Amsterdam, Netherlands
[32] Radboud Univ Nijmegen, Med Ctr, Rheumatol, Nijmegen, Netherlands
[33] Helsinki Univ Hosp, Dept Med, Helsinki, Finland
[34] Helsinki Univ Hosp, Dept Rheumatol, Helsinki, Finland
[35] Turku Univ Hosp, Ctr Rheumatol & Clin Immunol, Div Internal Med, Turku, Finland
[36] Turku Univ Hosp, Turku, Finland
[37] Univ Porto, Fac Med, Dept Med, Porto, Portugal
[38] Ctr Hosp & Univ Sao Joao, Rheumatol Dept, Porto, Portugal