[1] Hosp Univ La Paz, Dept Rheumatol, IdiPaz, Madrid, Spain
[2] Inst Rehabil Psicofis IREP, Dept Rheumatol, Buenos Aires, DF, Argentina
[3] Leiden Univ, Dept Rheumatol, Med Ctr, Leiden, Netherlands
[4] Univ Amsterdam, Dept Clin Immunol & Rheumatol, Med Ctr, Amsterdam, Netherlands
[5] Zuyderland Med Ctr, Dept Rheumatol, Heerlen, Netherlands
[6] Charite, Dept Gastroenterol Infectiol & Rheumatol, Berlin, Germany
[7] Maastricht Univ, Med Ctr, Maastricht, Netherlands
[8] Maastricht Univ, Sch Publ Hlth & Primary Care CAPHRI, Div Rheumatol, Dept Med, Maastricht, Netherlands
[9] Univ Sheffield, Sch Hlth & Related Res, Sheffield, S Yorkshire, England