[1] Toronto Western Hosp, Toronto, ON, Canada
[2] Johns Hopkins Univ, Sch Med, Baltimore, MD USA
[3] Univ Calgary, Calgary, AB, Canada
[4] Univ Birmingham, Birmingham, AL USA
[5] Hanyang Univ, Hosp Rheumat Dis, Seoul 133791, South Korea
[6] UCL, London, England
[7] Hairmyres Hosp, Glasgow, Lanark, Scotland
[8] Albert Einstein Coll Med, Bronx, NY 10467 USA
[9] Univ N Carolina, Chapel Hill, NC USA
[10] Univ Lund Hosp, S-22185 Lund, Sweden
[11] Landspitalinn Univ Hosp, Reykjavik, Iceland
[12] Univ Alabama, Birmingham, AL USA
[13] Univ Montreal, Sch Med, Montreal, PQ, Canada
[14] Hop Notre Dame de Bon Secours, Montreal, PQ H2L 4K8, Canada
[15] Hop Maison Neuve Rosemont, Montreal, PQ H1T 2M4, Canada
[16] Dalhousie Univ, Halifax, NS, Canada
[17] Queen Elizabeth 2 Hlth Sci Ctr, Halifax, NS, Canada
[18] Univ British Columbia, Vancouver, BC V5Z 1M9, Canada
[19] Univ Western Ontario, St Josephs Hosp, London, ON, Canada
[20] Royal Univ Hosp, Saskatoon, SK S7N 0W8, Canada
[21] Univ Manitoba, Winnipeg, MB, Canada
[22] Northwestern Univ, Chicago, IL 60611 USA