title: Disease Characteristics and Rheumatoid Arthritis Development in Patients with Early Undifferentiated Arthritis: A 2-year Followup Study.
abstract: To examine the 2-year disease course in patients with undifferentiated arthritis (UA) focusing on fulfillment of the 2010 American College of Rheumatology/European League Against Rheumatism (ACR/EULAR) rheumatoid arthritis (RA) classification criteria.
  
  
  
  Data were provided by the Norwegian Very Early Arthritis Clinic study, which included patients presenting with ≥ 1 swollen joint of ≤ 16 weeks' duration. UA was defined as patients not fulfilling the 2010 ACR/EULAR RA criteria and who did not have a clinical diagnosis other than RA at baseline. The main outcome was fulfillment of the 2010 RA criteria. Secondary outcomes were disease-modifying antirheumatic drug (DMARD) use, resolution of synovitis without use of DMARD during followup, and final clinical diagnosis.
  
  
  
  We included 477 patients with UA of whom 47 fulfilled the 2010 ACR/EULAR RA criteria during followup (UA-RA) and 430 did not (UA-non-RA). Of the UA-RA patients, 70% fulfilled the criteria within the first 6 months. UA-RA patients were older, more often positive for rheumatoid factor and anticitrullinated protein antibodies, female, and ever smokers, and they more often presented with polyarticular arthritis, small joint involvement, and a swollen shoulder joint. During followup, 53% of UA-RA patients vs 13% of UA-non-RA patients used DMARD (p < 0.001). Overall, 71% of patients with UA achieved absence of clinical synovitis at final followup without use of DMARD. The most frequent final clinical diagnosis was UA (61%).
  
  
  
  Only 9.8% of patients with UA fulfilled the 2010 RA criteria during 2-year followup. Small joint involvement and swollen shoulder joint were among the factors associated with RA development. In two-thirds of patients with UA, the arthritis resolved without use of DMARD.
authors.affiliation: From the Department of Rheumatology, Østfold Hospital Trust, Grålum; Department of Rheumatology, Martina Hansens Hospital, Bærum; Department of Rheumatology, Diakonhjemmet Hospital, Oslo; Department of Rheumatology, Lillehammer Hospital for Rheumatic Diseases, Lillehammer; Department of Rheumatology, Betanien Hospital, Skien, Norway. gina_hetland@hotmail.com.|G.H. Brinkmann, MD, Department of Rheumatology, Østfold Hospital Trust; E.S. Norli, MD, Department of Rheumatology, Martina Hansens Hospital; T.K. Kvien, MD, PhD, professor, Department of Rheumatology, Diakonhjemmet Hospital; A.J. Haugen, MD, PhD, Department of Rheumatology, Østfold Hospital Trust; L. Grøvle, MD, PhD, Department of Rheumatology, Østfold Hospital Trust; H. Nygaard, MD, Department of Rheumatology, Lillehammer Hospital for Rheumatic Diseases; O. Bjørneboe, MD, Department of Rheumatology, Martina Hansens Hospital; C. Thunem, MD, Department of Rheumatology, Betanien Hospital; M.D. Mjaavatten, MD, PhD, Department of Rheumatology, Diakonhjemmet Hospital; E. Lie, MD, PhD, Department of Rheumatology, Diakonhjemmet Hospital. gina_hetland@hotmail.com.
authors.forename: Gina H
authors.initials: GH
authors.lastname: Brinkmann
authors.affiliation: From the Department of Rheumatology, Østfold Hospital Trust, Grålum; Department of Rheumatology, Martina Hansens Hospital, Bærum; Department of Rheumatology, Diakonhjemmet Hospital, Oslo; Department of Rheumatology, Lillehammer Hospital for Rheumatic Diseases, Lillehammer; Department of Rheumatology, Betanien Hospital, Skien, Norway.|G.H. Brinkmann, MD, Department of Rheumatology, Østfold Hospital Trust; E.S. Norli, MD, Department of Rheumatology, Martina Hansens Hospital; T.K. Kvien, MD, PhD, professor, Department of Rheumatology, Diakonhjemmet Hospital; A.J. Haugen, MD, PhD, Department of Rheumatology, Østfold Hospital Trust; L. Grøvle, MD, PhD, Department of Rheumatology, Østfold Hospital Trust; H. Nygaard, MD, Department of Rheumatology, Lillehammer Hospital for Rheumatic Diseases; O. Bjørneboe, MD, Department of Rheumatology, Martina Hansens Hospital; C. Thunem, MD, Department of Rheumatology, Betanien Hospital; M.D. Mjaavatten, MD, PhD, Department of Rheumatology, Diakonhjemmet Hospital; E. Lie, MD, PhD, Department of Rheumatology, Diakonhjemmet Hospital.
authors.forename: Ellen S
authors.initials: ES
authors.lastname: Norli
authors.affiliation: From the Department of Rheumatology, Østfold Hospital Trust, Grålum; Department of Rheumatology, Martina Hansens Hospital, Bærum; Department of Rheumatology, Diakonhjemmet Hospital, Oslo; Department of Rheumatology, Lillehammer Hospital for Rheumatic Diseases, Lillehammer; Department of Rheumatology, Betanien Hospital, Skien, Norway.|G.H. Brinkmann, MD, Department of Rheumatology, Østfold Hospital Trust; E.S. Norli, MD, Department of Rheumatology, Martina Hansens Hospital; T.K. Kvien, MD, PhD, professor, Department of Rheumatology, Diakonhjemmet Hospital; A.J. Haugen, MD, PhD, Department of Rheumatology, Østfold Hospital Trust; L. Grøvle, MD, PhD, Department of Rheumatology, Østfold Hospital Trust; H. Nygaard, MD, Department of Rheumatology, Lillehammer Hospital for Rheumatic Diseases; O. Bjørneboe, MD, Department of Rheumatology, Martina Hansens Hospital; C. Thunem, MD, Department of Rheumatology, Betanien Hospital; M.D. Mjaavatten, MD, PhD, Department of Rheumatology, Diakonhjemmet Hospital; E. Lie, MD, PhD, Department of Rheumatology, Diakonhjemmet Hospital.
authors.forename: Tore K
authors.initials: TK
authors.lastname: Kvien
authors.affiliation: From the Department of Rheumatology, Østfold Hospital Trust, Grålum; Department of Rheumatology, Martina Hansens Hospital, Bærum; Department of Rheumatology, Diakonhjemmet Hospital, Oslo; Department of Rheumatology, Lillehammer Hospital for Rheumatic Diseases, Lillehammer; Department of Rheumatology, Betanien Hospital, Skien, Norway.|G.H. Brinkmann, MD, Department of Rheumatology, Østfold Hospital Trust; E.S. Norli, MD, Department of Rheumatology, Martina Hansens Hospital; T.K. Kvien, MD, PhD, professor, Department of Rheumatology, Diakonhjemmet Hospital; A.J. Haugen, MD, PhD, Department of Rheumatology, Østfold Hospital Trust; L. Grøvle, MD, PhD, Department of Rheumatology, Østfold Hospital Trust; H. Nygaard, MD, Department of Rheumatology, Lillehammer Hospital for Rheumatic Diseases; O. Bjørneboe, MD, Department of Rheumatology, Martina Hansens Hospital; C. Thunem, MD, Department of Rheumatology, Betanien Hospital; M.D. Mjaavatten, MD, PhD, Department of Rheumatology, Diakonhjemmet Hospital; E. Lie, MD, PhD, Department of Rheumatology, Diakonhjemmet Hospital.
authors.forename: Anne J
authors.initials: AJ
authors.lastname: Haugen
authors.affiliation: From the Department of Rheumatology, Østfold Hospital Trust, Grålum; Department of Rheumatology, Martina Hansens Hospital, Bærum; Department of Rheumatology, Diakonhjemmet Hospital, Oslo; Department of Rheumatology, Lillehammer Hospital for Rheumatic Diseases, Lillehammer; Department of Rheumatology, Betanien Hospital, Skien, Norway.|G.H. Brinkmann, MD, Department of Rheumatology, Østfold Hospital Trust; E.S. Norli, MD, Department of Rheumatology, Martina Hansens Hospital; T.K. Kvien, MD, PhD, professor, Department of Rheumatology, Diakonhjemmet Hospital; A.J. Haugen, MD, PhD, Department of Rheumatology, Østfold Hospital Trust; L. Grøvle, MD, PhD, Department of Rheumatology, Østfold Hospital Trust; H. Nygaard, MD, Department of Rheumatology, Lillehammer Hospital for Rheumatic Diseases; O. Bjørneboe, MD, Department of Rheumatology, Martina Hansens Hospital; C. Thunem, MD, Department of Rheumatology, Betanien Hospital; M.D. Mjaavatten, MD, PhD, Department of Rheumatology, Diakonhjemmet Hospital; E. Lie, MD, PhD, Department of Rheumatology, Diakonhjemmet Hospital.
authors.forename: Lars
authors.initials: L
authors.lastname: Grøvle
authors.affiliation: From the Department of Rheumatology, Østfold Hospital Trust, Grålum; Department of Rheumatology, Martina Hansens Hospital, Bærum; Department of Rheumatology, Diakonhjemmet Hospital, Oslo; Department of Rheumatology, Lillehammer Hospital for Rheumatic Diseases, Lillehammer; Department of Rheumatology, Betanien Hospital, Skien, Norway.|G.H. Brinkmann, MD, Department of Rheumatology, Østfold Hospital Trust; E.S. Norli, MD, Department of Rheumatology, Martina Hansens Hospital; T.K. Kvien, MD, PhD, professor, Department of Rheumatology, Diakonhjemmet Hospital; A.J. Haugen, MD, PhD, Department of Rheumatology, Østfold Hospital Trust; L. Grøvle, MD, PhD, Department of Rheumatology, Østfold Hospital Trust; H. Nygaard, MD, Department of Rheumatology, Lillehammer Hospital for Rheumatic Diseases; O. Bjørneboe, MD, Department of Rheumatology, Martina Hansens Hospital; C. Thunem, MD, Department of Rheumatology, Betanien Hospital; M.D. Mjaavatten, MD, PhD, Department of Rheumatology, Diakonhjemmet Hospital; E. Lie, MD, PhD, Department of Rheumatology, Diakonhjemmet Hospital.
authors.forename: Halvor
authors.initials: H
authors.lastname: Nygaard
authors.affiliation: From the Department of Rheumatology, Østfold Hospital Trust, Grålum; Department of Rheumatology, Martina Hansens Hospital, Bærum; Department of Rheumatology, Diakonhjemmet Hospital, Oslo; Department of Rheumatology, Lillehammer Hospital for Rheumatic Diseases, Lillehammer; Department of Rheumatology, Betanien Hospital, Skien, Norway.|G.H. Brinkmann, MD, Department of Rheumatology, Østfold Hospital Trust; E.S. Norli, MD, Department of Rheumatology, Martina Hansens Hospital; T.K. Kvien, MD, PhD, professor, Department of Rheumatology, Diakonhjemmet Hospital; A.J. Haugen, MD, PhD, Department of Rheumatology, Østfold Hospital Trust; L. Grøvle, MD, PhD, Department of Rheumatology, Østfold Hospital Trust; H. Nygaard, MD, Department of Rheumatology, Lillehammer Hospital for Rheumatic Diseases; O. Bjørneboe, MD, Department of Rheumatology, Martina Hansens Hospital; C. Thunem, MD, Department of Rheumatology, Betanien Hospital; M.D. Mjaavatten, MD, PhD, Department of Rheumatology, Diakonhjemmet Hospital; E. Lie, MD, PhD, Department of Rheumatology, Diakonhjemmet Hospital.
authors.forename: Olav
authors.initials: O
authors.lastname: Bjørneboe
authors.affiliation: From the Department of Rheumatology, Østfold Hospital Trust, Grålum; Department of Rheumatology, Martina Hansens Hospital, Bærum; Department of Rheumatology, Diakonhjemmet Hospital, Oslo; Department of Rheumatology, Lillehammer Hospital for Rheumatic Diseases, Lillehammer; Department of Rheumatology, Betanien Hospital, Skien, Norway.|G.H. Brinkmann, MD, Department of Rheumatology, Østfold Hospital Trust; E.S. Norli, MD, Department of Rheumatology, Martina Hansens Hospital; T.K. Kvien, MD, PhD, professor, Department of Rheumatology, Diakonhjemmet Hospital; A.J. Haugen, MD, PhD, Department of Rheumatology, Østfold Hospital Trust; L. Grøvle, MD, PhD, Department of Rheumatology, Østfold Hospital Trust; H. Nygaard, MD, Department of Rheumatology, Lillehammer Hospital for Rheumatic Diseases; O. Bjørneboe, MD, Department of Rheumatology, Martina Hansens Hospital; C. Thunem, MD, Department of Rheumatology, Betanien Hospital; M.D. Mjaavatten, MD, PhD, Department of Rheumatology, Diakonhjemmet Hospital; E. Lie, MD, PhD, Department of Rheumatology, Diakonhjemmet Hospital.
authors.forename: Cathrine
authors.initials: C
authors.lastname: Thunem
authors.affiliation: From the Department of Rheumatology, Østfold Hospital Trust, Grålum; Department of Rheumatology, Martina Hansens Hospital, Bærum; Department of Rheumatology, Diakonhjemmet Hospital, Oslo; Department of Rheumatology, Lillehammer Hospital for Rheumatic Diseases, Lillehammer; Department of Rheumatology, Betanien Hospital, Skien, Norway.|G.H. Brinkmann, MD, Department of Rheumatology, Østfold Hospital Trust; E.S. Norli, MD, Department of Rheumatology, Martina Hansens Hospital; T.K. Kvien, MD, PhD, professor, Department of Rheumatology, Diakonhjemmet Hospital; A.J. Haugen, MD, PhD, Department of Rheumatology, Østfold Hospital Trust; L. Grøvle, MD, PhD, Department of Rheumatology, Østfold Hospital Trust; H. Nygaard, MD, Department of Rheumatology, Lillehammer Hospital for Rheumatic Diseases; O. Bjørneboe, MD, Department of Rheumatology, Martina Hansens Hospital; C. Thunem, MD, Department of Rheumatology, Betanien Hospital; M.D. Mjaavatten, MD, PhD, Department of Rheumatology, Diakonhjemmet Hospital; E. Lie, MD, PhD, Department of Rheumatology, Diakonhjemmet Hospital.
authors.forename: Maria D
authors.initials: MD
authors.lastname: Mjaavatten
authors.affiliation: From the Department of Rheumatology, Østfold Hospital Trust, Grålum; Department of Rheumatology, Martina Hansens Hospital, Bærum; Department of Rheumatology, Diakonhjemmet Hospital, Oslo; Department of Rheumatology, Lillehammer Hospital for Rheumatic Diseases, Lillehammer; Department of Rheumatology, Betanien Hospital, Skien, Norway.|G.H. Brinkmann, MD, Department of Rheumatology, Østfold Hospital Trust; E.S. Norli, MD, Department of Rheumatology, Martina Hansens Hospital; T.K. Kvien, MD, PhD, professor, Department of Rheumatology, Diakonhjemmet Hospital; A.J. Haugen, MD, PhD, Department of Rheumatology, Østfold Hospital Trust; L. Grøvle, MD, PhD, Department of Rheumatology, Østfold Hospital Trust; H. Nygaard, MD, Department of Rheumatology, Lillehammer Hospital for Rheumatic Diseases; O. Bjørneboe, MD, Department of Rheumatology, Martina Hansens Hospital; C. Thunem, MD, Department of Rheumatology, Betanien Hospital; M.D. Mjaavatten, MD, PhD, Department of Rheumatology, Diakonhjemmet Hospital; E. Lie, MD, PhD, Department of Rheumatology, Diakonhjemmet Hospital.
authors.forename: Elisabeth
authors.initials: E
authors.lastname: Lie
mesh_terms: D000328:Adult; D000368:Aged; D018501:Antirheumatic Agents / Q000627:therapeutic use; D001168:Arthritis / Q000175:diagnosis* / Q000188:drug therapy; D001172:Arthritis, Rheumatoid / Q000175:diagnosis* / Q000188:drug therapy; D018450:Disease Progression; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008297:Male; D008875:Middle Aged; D011379:Prognosis; D012720:Severity of Illness Index; D063189:Symptom Assessment; D013585:Synovitis / Q000175:diagnosis* / Q000188:drug therapy
chemical_list: D018501:Antirheumatic Agents
keywords: DISEASE-MODIFYING ANTIRHEUMATIC DRUGS; EPIDEMIOLOGY; PROGNOSIS; RHEUMATOID ARTHRITIS; TREATMENT OUTCOME