[1] Nova Scotia Rehabil Ctr, Div Rheumatol, Queen Elizabeth II Hlth Ctr, Halifax, NS B3H 4K4, Canada
[2] Dalhousie Univ, Halifax, NS, Canada
[3] Toronto Western Hosp, Toronto, ON M5T 2S8, Canada
[4] Univ Toronto, Toronto, ON, Canada
[5] Univ Athens, Athens, Greece
[6] Cambridge Univ Forvie Site, Cambridge, England
[7] Univ Birmingham, Birmingham, W Midlands, England
[8] Royal Natl Hosp Rheumat Dis, Seoul, South Korea
[9] UCL, London, England
[10] Univ N Carolina, Chapel Hill, NC USA
[11] Montreal Gen Hosp, Montreal, PQ H3G 1A4, Canada
[12] McGill Univ, Ctr Hlth, Montreal, PQ, Canada
[13] Univ Pittsburgh, Sch Med, Pittsburgh, PA USA
[14] Landspitali Univ Hosp, Reykjavik, Iceland
[15] Manchester Royal Infirm, Manchester M13 9WL, Lancs, England
[16] Univ Manchester, Manchester M13 9WL, Lancs, England
[17] SUNY Hlth Sci Ctr, Brooklyn, NY 11203 USA
[18] Columbia Univ, Med Ctr, New York, NY USA
[19] Univ Calif Los Angeles, Los Angeles, CA USA
[20] Northwestern Univ, Chicago, IL 60611 USA
[21] Karolinska Univ Hosp, Stockholm, Sweden
[22] Univ Lund Hosp, S-22185 Lund, Sweden
[23] Inst Nacl Ciencias Med & Nutr Salvador Zubiran, Mexico City, DF, Mexico
[24] Univ Alabama Birmingham, Birmingham, AL USA
[25] Johns Hopkins Univ, Baltimore, MD USA
[26] St Thomas Hosp, London, England
[27] Kings Coll London, London WC2R 2LS, England
[28] Hairmyres Hosp, E Kilbride, Lanark, Scotland
[29] Univ Calif San Diego, San Diego, CA 92103 USA
[30] Oklahoma Med Res Fdn, Oklahoma City, OK USA