Sorlandet Hospital - Research Department, Martina Hansen Hospital - Department of Rheumatology, Diakonhjemmet Hospital - Division of Rheumatology and Research, University of Bergen - Bergen Group of Epidemiology and Biomarkers in Rheumatic Disease, Haugesund Hospital for Rheumatic Diseases, Lillehammer Hospital for Rheumatic Diseases, Betanien Hospital - Department of Rheumatology, Trondheim University Hospital - Department of Rheumatology, University Hospital of North Norway - Department of Rheumatology, District General Hospital of Førde - Section for Rheumatology and Sorlandet Hospital - Research Department