[1] Rigshosp, DANBIO Registry, Glostrup, Denmark
[2] Rigshosp, Copenhagen Ctr Arthrit Res, Ctr Rheumatol & Spine Dis, Glostrup, Denmark
[3] Univ Copenhagen, Fac Hlth & Med Sci, Dept Clin Med, Copenhagen, Denmark
[4] Gentofte Univ Hosp, Ctr Rheumatol & Spine Dis, Hellerup, Denmark
[5] Aarhus Univ, Dept Clin Epidemiol, Aarhus, Denmark
[6] Univ Southern Denmark, Dept Publ Hlth, Odense, Denmark