title: Palindromic rheumatism with positive anticitrullinated peptide/protein antibodies is not synonymous with rheumatoid arthritis. A longterm followup study.
abstract: OBJECTIVE
  To analyze longterm progression to rheumatoid arthritis (RA) and the predictive value of anticitrullinated peptide/protein antibodies (ACPA) in palindromic rheumatism (PR).
  
  
  METHODS
  We selected all patients in our clinic with PR who had at least 1 ACPA measurement. We included only patients with pure PR, defined as no evidence of associated rheumatic disease at the first serum ACPA measurement. Clinical characteristics, serum ACPA levels, duration of PR until serum ACPA measurement, and total followup time were recorded. The outcome variable was the definitive diagnosis of RA. The prognostic value of ACPA status in pure PR for a definite diagnosis of RA was analyzed by different statistical methods.
  
  
  RESULTS
  Seventy-one patients (54 women/17 men) with a PR diagnosis were included. Serum ACPA were positive in 52.1%. After a mean followup of 7.6 ± 4.7 years since the first ACPA measurement, 24 patients (33.8%) progressed to chronic disease: 22% RA, 5.6% systemic lupus erythematosus, and 5.6% other diseases. The positive likelihood ratio of ACPA status for RA was 1.45, and the area under the receiver-operating characteristic curve of ACPA titers was 0.60 (95% CI 0.45-0.75). Progression to RA was more frequently seen in ACPA-positive than in ACPA-negative patients (29.7% vs 14.7%), but the difference was not significant (hazard ratio 2.46, 95% CI 0.77-7.86). Mean ACPA levels of patients with pure PR did not differ significantly from those of patients who progressed to RA.
  
  
  CONCLUSIONS
  ACPA are frequently found in the sera of patients with PR, and a significant proportion of these patients do not progress to RA in the long term.
authors.affiliation: Arthritis Unit, Rheumatology Service, Hospital Clínic of Barcelona, Barcelona, Spain. sanmarti@clinic.ub.es
authors.forename: Raimon
authors.initials: R
authors.lastname: Sanmartí
authors.forename: Sonia
authors.initials: S
authors.lastname: Cabrera-Villalba
authors.forename: José A
authors.initials: JA
authors.lastname: Gómez-Puerta
authors.forename: Virginia
authors.initials: V
authors.lastname: Ruiz-Esquide
authors.forename: M Victoria
authors.initials: MV
authors.lastname: Hernández
authors.forename: Georgina
authors.initials: G
authors.lastname: Salvador
authors.forename: Julio
authors.initials: J
authors.lastname: Ramirez
authors.forename: Odette
authors.initials: O
authors.lastname: Viñas
authors.forename: Juan D
authors.initials: JD
authors.lastname: Cañete
mesh_terms: D000328:Adult; D000368:Aged; D001172:Arthritis, Rheumatoid / Q000097:blood / Q000276:immunology*; D001323:Autoantibodies / Q000097:blood / Q000276:immunology*; D018450:Disease Progression; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008137:Longitudinal Studies; D008297:Male; D008875:Middle Aged; D010456:Peptides, Cyclic / Q000097:blood / Q000276:immunology*; D011379:Prognosis
chemical_list: D001323:Autoantibodies; D010456:Peptides, Cyclic; C487763:cyclic citrullinated peptide