title: The 12-item Psoriatic Arthritis Impact of Disease Questionnaire: Construct Validity, Reliability, and Interpretability in a Clinical Setting.
abstract: To study, in a real-life setting, the construct validity, the reliability, and the interpretability of the 12-item Psoriatic Arthritis Impact of Disease (PsAID-12) questionnaire in patients with psoriatic arthritis (PsA).
  
  
  
  In 144 consecutive patients with PsA (81 men and 63 women, mean age of 51.4 ± 12.8 yrs, and 77 receiving biologic treatment), the PsAID-12 and other patient-reported outcomes (PRO) were collected, such as the Dermatology Life Quality Index. Each patient underwent articular and skin assessment.
  
  
  
  Construct validity: Factor analysis revealed a 2-factor result defined as the PsAID Symptom Score and the PsAID Skin Score. In determining convergent validity, significant correlations were found between the PsAID-12 and the clinical Disease Activity index for Psoriatic Arthritis (cDAPSA; ρ = 0.867, p < 0.0001). Multivariable analysis showed that the PsAID-12 is determined by the articular disease activity (cDAPSA, p < 0.0001), severity of psoriasis (PsO; physician's global assessment, p < 0.0001), and the presence of a coexisting fibromyalgia (FM; p < 0.0001). Reliability: Cronbach's alpha coefficient was 0.93 for the total PsAID-12. Interpretability: Applying the cDAPSA categorization of disease activity states, the PsAID-12 cutoff values resulted in 1.4 between remission and low disease activity (LDA), 4.1 between LDA and moderate disease activity (MDA), and 6.7 between MDA and high disease activity.
  
  
  
  The PsAID-12 is an excellent PRO to evaluate the effect of PsA. It should be carefully handled in patients with coexisting FM.
authors.affiliation: From the Rheumatology Department, Polytechnic University of Marche, Jesi; Rheumatology Department, Istituto Ortopedico Gaetano Pini, Milan; Clinical and Community Sciences Department, University of Milan, Milan, Italy. dica.marco@yahoo.it.|M. Di Carlo, MD, Rheumatology Department, Polytechnic University of Marche; A. Becciolini, MD, Rheumatology Department, Istituto Ortopedico Gaetano Pini; V. Lato, MD, Rheumatology Department, Polytechnic University of Marche; C. Crotti, MD, Clinical and Community Sciences Department, University of Milan; E.G. Favalli, MD, Rheumatology Department, Istituto Ortopedico Gaetano Pini; F. Salaffi, MD, PhD, Rheumatology Department, Polytechnic University of Marche. dica.marco@yahoo.it.
authors.forename: Marco
authors.initials: M
authors.lastname: Di Carlo
authors.affiliation: From the Rheumatology Department, Polytechnic University of Marche, Jesi; Rheumatology Department, Istituto Ortopedico Gaetano Pini, Milan; Clinical and Community Sciences Department, University of Milan, Milan, Italy.|M. Di Carlo, MD, Rheumatology Department, Polytechnic University of Marche; A. Becciolini, MD, Rheumatology Department, Istituto Ortopedico Gaetano Pini; V. Lato, MD, Rheumatology Department, Polytechnic University of Marche; C. Crotti, MD, Clinical and Community Sciences Department, University of Milan; E.G. Favalli, MD, Rheumatology Department, Istituto Ortopedico Gaetano Pini; F. Salaffi, MD, PhD, Rheumatology Department, Polytechnic University of Marche.
authors.forename: Andrea
authors.initials: A
authors.lastname: Becciolini
authors.affiliation: From the Rheumatology Department, Polytechnic University of Marche, Jesi; Rheumatology Department, Istituto Ortopedico Gaetano Pini, Milan; Clinical and Community Sciences Department, University of Milan, Milan, Italy.|M. Di Carlo, MD, Rheumatology Department, Polytechnic University of Marche; A. Becciolini, MD, Rheumatology Department, Istituto Ortopedico Gaetano Pini; V. Lato, MD, Rheumatology Department, Polytechnic University of Marche; C. Crotti, MD, Clinical and Community Sciences Department, University of Milan; E.G. Favalli, MD, Rheumatology Department, Istituto Ortopedico Gaetano Pini; F. Salaffi, MD, PhD, Rheumatology Department, Polytechnic University of Marche.
authors.forename: Valentina
authors.initials: V
authors.lastname: Lato
authors.affiliation: From the Rheumatology Department, Polytechnic University of Marche, Jesi; Rheumatology Department, Istituto Ortopedico Gaetano Pini, Milan; Clinical and Community Sciences Department, University of Milan, Milan, Italy.|M. Di Carlo, MD, Rheumatology Department, Polytechnic University of Marche; A. Becciolini, MD, Rheumatology Department, Istituto Ortopedico Gaetano Pini; V. Lato, MD, Rheumatology Department, Polytechnic University of Marche; C. Crotti, MD, Clinical and Community Sciences Department, University of Milan; E.G. Favalli, MD, Rheumatology Department, Istituto Ortopedico Gaetano Pini; F. Salaffi, MD, PhD, Rheumatology Department, Polytechnic University of Marche.
authors.forename: Chiara
authors.initials: C
authors.lastname: Crotti
authors.affiliation: From the Rheumatology Department, Polytechnic University of Marche, Jesi; Rheumatology Department, Istituto Ortopedico Gaetano Pini, Milan; Clinical and Community Sciences Department, University of Milan, Milan, Italy.|M. Di Carlo, MD, Rheumatology Department, Polytechnic University of Marche; A. Becciolini, MD, Rheumatology Department, Istituto Ortopedico Gaetano Pini; V. Lato, MD, Rheumatology Department, Polytechnic University of Marche; C. Crotti, MD, Clinical and Community Sciences Department, University of Milan; E.G. Favalli, MD, Rheumatology Department, Istituto Ortopedico Gaetano Pini; F. Salaffi, MD, PhD, Rheumatology Department, Polytechnic University of Marche.
authors.forename: Ennio Giulio
authors.initials: EG
authors.lastname: Favalli
authors.affiliation: From the Rheumatology Department, Polytechnic University of Marche, Jesi; Rheumatology Department, Istituto Ortopedico Gaetano Pini, Milan; Clinical and Community Sciences Department, University of Milan, Milan, Italy.|M. Di Carlo, MD, Rheumatology Department, Polytechnic University of Marche; A. Becciolini, MD, Rheumatology Department, Istituto Ortopedico Gaetano Pini; V. Lato, MD, Rheumatology Department, Polytechnic University of Marche; C. Crotti, MD, Clinical and Community Sciences Department, University of Milan; E.G. Favalli, MD, Rheumatology Department, Istituto Ortopedico Gaetano Pini; F. Salaffi, MD, PhD, Rheumatology Department, Polytechnic University of Marche.
authors.forename: Fausto
authors.initials: F
authors.lastname: Salaffi
mesh_terms: D000328:Adult; D000368:Aged; D015535:Arthritis, Psoriatic / Q000175:diagnosis*; D004185:Disability Evaluation; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D015203:Reproducibility of Results; D012720:Severity of Illness Index; D063189:Symptom Assessment
keywords: PATIENT-REPORTED OUTCOMES; PSORIATIC ARTHRITIS; PsAID-12