title: Rasch Analysis of the Italian version of Pain Catastrophizing Scale (PCS-I).
abstract: OBJECTIVE
  The aim of this study was to investigate the psychometric properties of the Italian version of the Pain Catastrophizing Scale (PCS-I) in patients with chronic low back pain.
  
  
  METHODS
  In a cross sectional study a total of 150 subjects with chronic low back pain were included. The Italian translation of the PCS was administered to all subjects. The properties of the Italian version of the PCS were explored by a Rasch analysis.
  
  
  RESULTS
  The PCS-I, by means of few modifications, fitted the Rasch model and passed the independent t-test for a unidimensional scale. The response categories for item 2 ``I fell I can't go on'' needed to be collapsed from 4 to 3 levels. Only the item 7 ``I keep thinking to of other painful events'' showed fit residual that exceeded the chosen thresholds of ± 2.5. No Differential functioning (DIF) was observed for age, sex, marital status, BMI and smoking.
  
  
  CONCLUSIONS
  The Italian version of PCS, with the purposed modifications, seems to reflect a unidimensional construct of Pain Catastrophizing. The scale seemed to be quite robust across age, sex, marital status, BMI and smoking. Targeting of the scale was moderate. A raw score to metric conversion was proposed.
authors.affiliation: Department of Translational Medicine and Surgery, PhD Program in Neuroscience, University of Milan Bicocca, Carate Brianza, Italy.
authors.forename: Roberto
authors.initials: R
authors.lastname: Meroni
authors.affiliation: Department of Translational Medicine and Surgery, PhD Program in Neuroscience, University of Milan Bicocca, Carate Brianza, Italy.
authors.forename: Daniele
authors.initials: D
authors.lastname: Piscitelli
authors.affiliation: Studio Fisio Bonetti, Roma, Italy.
authors.forename: Francesca
authors.initials: F
authors.lastname: Bonetti
authors.affiliation: Centro di Fisioterapia e Medicina dello Sport Kinesi, Trento, Italy.
authors.forename: Mattia
authors.initials: M
authors.lastname: Zambaldi
authors.affiliation: Department of Translational Medicine and Surgery, PhD Program in Neuroscience, University of Milan Bicocca, Carate Brianza, Italy.
authors.forename: Cesare G
authors.initials: CG
authors.lastname: Cerri
authors.affiliation: Department of Rehabilitation Science, College of Health and Human Services, George Mason University, Fairfax, VA, USA.
authors.forename: Andrew A
authors.initials: AA
authors.lastname: Guccione
authors.affiliation: Department of Biomedical and Neuromotor Sciences, University of Bologna, PT, Italy.
authors.forename: Paolo
authors.initials: P
authors.lastname: Pillastrini
mesh_terms: D000058:Accidental Falls; D000328:Adult; D058443:Catastrophization / Q000175:diagnosis*; D003430:Cross-Sectional Studies; D005260:Female; D006801:Humans; D007558:Italy; D017116:Low Back Pain / Q000175:diagnosis*; D008297:Male; D008875:Middle Aged; D010147:Pain Measurement / Q000379:methods; D011594:Psychometrics; D012720:Severity of Illness Index; D011795:Surveys and Questionnaires; D014177:Translations
keywords: LBP; PCS; PCS-I; Pain; Rasch Analysis; chronic low back pain