title: Identification of the clinical features distinguishing psoriatic arthritis and fibromyalgia.
abstract: OBJECTIVE
  To identify the clinical features that can help to distinguish between psoriatic arthritis (PsA) and fibromyalgia (FM).
  
  
  METHODS
  Our cross-sectional study was carried out in 10 Italian rheumatology centers between January and September 2009, and enrolled all consecutive patients with PsA and FM who agreed to participate. Standard clinical and laboratory data for PsA and FM were collected from all patients. Records were made of somatic symptoms, response to nonsteroidal antiinflammatory drugs (NSAID), self-evaluated pain, general health, disability, and responses to the Fibromyalgia Impact Questionnaire. Data were statistically analyzed by univariate and multivariate analyses, and receiver-operating characteristic curves. The analysis concentrated on the clinical features shared by the 2 conditions.
  
  
  RESULTS
  Two hundred sixty-six patients with PsA (mean age 51.7 yrs; disease duration 10.2 yrs) and 120 patients with FM (mean age 50.2 yrs; disease duration 5.6 yrs) were evaluated. Univariate analysis showed that patients with FM had higher mean tender point and enthesitis scores, more somatic symptoms, and responded less to NSAID. Multivariate analysis showed that the presence of ≥ 6 FM-associated symptoms and ≥ 8 tender points was the best predictor of FM.
  
  
  CONCLUSIONS
  The shared clinical features of PsA and FM that had the greatest discriminating power for FM were the number of FM-associated symptoms and tender point count.
authors.affiliation: UOC Day Hospital of Rheumatology, Istituto Ortopedico Gaetano Pini, Piazza A. Ferrari 1, 20122 Milan, Italy. marchesoni@gpini.it
authors.forename: Antonio
authors.initials: A
authors.lastname: Marchesoni
authors.forename: Fabiola
authors.initials: F
authors.lastname: Atzeni
authors.forename: Antonio
authors.initials: A
authors.lastname: Spadaro
authors.forename: Ennio
authors.initials: E
authors.lastname: Lubrano
authors.forename: Giuseppe
authors.initials: G
authors.lastname: Provenzano
authors.forename: Alberto
authors.initials: A
authors.lastname: Cauli
authors.forename: Ignazio
authors.initials: I
authors.lastname: Olivieri
authors.forename: Daniela
authors.initials: D
authors.lastname: Melchiorre
authors.forename: Carlo
authors.initials: C
authors.lastname: Salvarani
authors.forename: Raffaele
authors.initials: R
authors.lastname: Scarpa
authors.forename: Piercarlo
authors.initials: P
authors.lastname: Sarzi-Puttini
authors.forename: Monica
authors.initials: M
authors.lastname: Montepaone
authors.forename: Giovanni
authors.initials: G
authors.lastname: Porru
authors.forename: Salvatore
authors.initials: S
authors.lastname: D'Angelo
authors.forename: Mariagrazia
authors.initials: M
authors.lastname: Catanoso
authors.forename: Luisa
authors.initials: L
authors.lastname: Costa
authors.forename: Maria
authors.initials: M
authors.lastname: Manara
authors.forename: Valentina
authors.initials: V
authors.lastname: Varisco
authors.forename: Laura
authors.initials: L
authors.lastname: Rotunno
authors.forename: Orazio
authors.initials: O
authors.lastname: DE Lucia
authors.forename: Gabriele
authors.initials: G
authors.lastname: DE Marco
mesh_terms: D000328:Adult; D015535:Arthritis, Psoriatic / Q000175:diagnosis* / Q000188:drug therapy / Q000503:physiopathology*; D003430:Cross-Sectional Studies; D003937:Diagnosis, Differential; D005260:Female; D005356:Fibromyalgia / Q000175:diagnosis* / Q000188:drug therapy / Q000503:physiopathology*; D006801:Humans; D008297:Male; D008875:Middle Aged