Affiliation: | 1. Oslo Univ. Hosp., Oslo, Norway;2. Inst. of Clinical Med., Univ. of Oslo, Oslo, Norway;3. Diakonhjemmet Hosp., Dept. of Rheumatology, the Natl. Advisory Unit on Rehabilitation in Rheumatology, Oslo, Norway;4. Diakonhjemmet Hosp., Dept. of Rheumatology, Oslo, Norway;5. Lund Univ., Faculty of Med., Dept. of Clinical Sci. Lund, Orthopaedics, Clinical Epidemiology Unit, Lund, Sweden |