[1] Bispebjerg & Frederiksberg Hosp, Parker Inst, Musculoskeletal Stat Unit, Copenhagen, Denmark
[2] Univ Calif Los Angeles, David Geffen Sch Med, Dept Med, Los Angeles, CA 90095 USA
[3] Glostrup Cty Hosp, Ctr Rheumatol & Spine Dis, Copenhagen Ctr Arthrit Res, Copenhagen, Denmark
[4] Univ Copenhagen, Dept Clin Med, Copenhagen, Denmark
[5] Silkeborg Reg Hosp, Ctr Diagnost, Dept Rheumatol, Copenhagen, Denmark
[6] ReumaKlin Roskilde, Roskilde, Denmark
[7] Gildhoj Privathosp, Brondby, Denmark
[8] VA Med Ctr, Med Serv, Birmingham, AL USA
[9] VA Med Ctr, Ctr Surg Med Acute Care Res & Transit, Birmingham, AL USA
[10] Univ Alabama Birmingham, Sch Publ Hlth, Div Epidemiol, Dept Med,Sch Med, Birmingham, AL 35294 USA
[11] Mayo Clin, Coll Med, Dept Orthoped Surg, Rochester, MN USA
[12] Arthrit Res UK, Rheumatol Sect, Cardiff, S Glam, Wales
[13] Cardiff Univ, Sch Med, Hlth & Care Res Wales CREATE Ctr, Cardiff, S Glam, Wales
[14] Vrije Univ Amsterdam, Med Ctr, Dept Epidemiol & Biostat, Amsterdam, Netherlands
[15] Vrije Univ Amsterdam, Med Ctr, Amsterdam Rheumatol & Immunol Ctr, Amsterdam, Netherlands
[16] Univ Texas MD Anderson Canc Ctr, Sect Rheumatol & Clin Immunol, Houston, TX 77030 USA