title: What is rheumatoid arthritis? Considering consequences of changed classification criteria.
authors.affiliation: Department of Rheumatology, Leiden University Medical Center, Leiden, The Netherlands.|Department of Rheumatology, Erasmus Medical Center, Rotterdam, The Netherlands.
authors.forename: Annette H M
authors.initials: AH
authors.lastname: van der Helm-van Mil
authors.affiliation: Epidemiology Unit, German Rheumatism Research Centre, Berlin, Germany.|Department for Rheumatology and Clinical Immunology, Charité University Medicine, Berlin Germany.
authors.forename: Angela
authors.initials: A
authors.lastname: Zink
mesh_terms: D018501:Antirheumatic Agents; D001172:Arthritis, Rheumatoid; D006801:Humans; D012217:Rheumatoid Factor
chemical_list: D018501:Antirheumatic Agents; D012217:Rheumatoid Factor
keywords: Autoantibodies; Disease Activity; Rheumatoid Arthritis