[1] Diakonhjemmet Hosp, Dept Rheumatol, Oslo, Norway
[2] Hosp Southern Norway Trust, Dept Rheumatol, Kristiansand, Norway
[3] Diakonhjemmet Hosp, Rheumatol, Oslo, Norway
[4] Martina Hansens Hosp, Dept Rheumatol, Berum, Norway
[5] Norwegian Univ Sci & Technol, Dept Rheumatol, Trondheim, Norway