title: The Dutch-Flemish PROMIS Physical Function item bank exhibited strong psychometric properties in patients with chronic pain.
abstract: OBJECTIVE
  The objective of this study was to assess the psychometric properties of the Dutch-Flemish Patient-Reported Outcomes Measurement Information System (PROMIS) Physical Function item bank in Dutch patients with chronic pain.
  
  
  METHODS
  A bank of 121 items was administered to 1,247 Dutch patients with chronic pain. Unidimensionality was assessed by fitting a one-factor confirmatory factor analysis and evaluating resulting fit statistics. Items were calibrated with the graded response model and its fit was evaluated. Cross-cultural validity was assessed by testing items for differential item functioning (DIF) based on language (Dutch vs. English). Construct validity was evaluated by calculation correlations between scores on the Dutch-Flemish PROMIS Physical Function measure and scores on generic and disease-specific measures.
  
  
  RESULTS
  Results supported the Dutch-Flemish PROMIS Physical Function item bank's unidimensionality (Comparative Fit Index = 0.976, Tucker Lewis Index = 0.976) and model fit. Item thresholds targeted a wide range of physical function construct (threshold-parameters range: -4.2 to 5.6). Cross-cultural validity was good as four items only showed DIF for language and their impact on item scores was minimal. Physical Function scores were strongly associated with scores on all other measures (all correlations ≤ -0.60 as expected).
  
  
  CONCLUSIONS
  The Dutch-Flemish PROMIS Physical Function item bank exhibited good psychometric properties. Development of a computer adaptive test based on the large bank is warranted.
authors.affiliation: Amsterdam Rehabilitation Research Center|Reade, Doctor Jan van Breemenstraat 2, Amsterdam 1056 AB, The Netherlands. Electronic address: m.crins@reade.nl.
authors.forename: Martine H P
authors.initials: MHP
authors.lastname: Crins
authors.affiliation: Department of Epidemiology and Biostatistics, The EMGO Institute for Health and Care Research, VU University Medical Center, Van der Boechorststraat 7, Amsterdam 1081, The Netherlands.
authors.forename: Caroline B
authors.initials: CB
authors.lastname: Terwee
authors.affiliation: Department of Epidemiology and Biostatistics, The EMGO Institute for Health and Care Research, VU University Medical Center, Van der Boechorststraat 7, Amsterdam 1081, The Netherlands.
authors.forename: Thomas
authors.initials: T
authors.lastname: Klausch
authors.affiliation: Research Institute of Child Development and Education, University of Amsterdam, Nieuwe Achtergracht 127, Amsterdam 1018 WS, The Netherlands.
authors.forename: Niels
authors.initials: N
authors.lastname: Smits
authors.affiliation: Department of Epidemiology and Biostatistics, The EMGO Institute for Health and Care Research, VU University Medical Center, Van der Boechorststraat 7, Amsterdam 1081, The Netherlands.
authors.forename: Henrica C W
authors.initials: HCW
authors.lastname: de Vet
authors.affiliation: Department of Development and Regeneration, Skeletal Biology and Engineering Research Center, KU Leuven, Herestraat 49, Leuven 3000, Belgium; Rheumatology, University Hospitals, KU Leuven, Herestraat 49, Leuven 3000, Belgium.
authors.forename: Rene
authors.initials: R
authors.lastname: Westhovens
authors.affiliation: Department of Medical Social Sciences, Northwestern University Feinberg School of Medicine, 633 N. Saint Clair Street, 19th Floor, Chicago, IL 60611, USA.
authors.forename: David
authors.initials: D
authors.lastname: Cella
authors.affiliation: Department of Medical Social Sciences, Northwestern University Feinberg School of Medicine, 633 N. Saint Clair Street, 19th Floor, Chicago, IL 60611, USA.
authors.forename: Karon F
authors.initials: KF
authors.lastname: Cook
authors.affiliation: Outcomes Research, Evidera, 7101 Wisconsin Ave., Suite 1400, Bethesda, MD 20814, USA.
authors.forename: Dennis A
authors.initials: DA
authors.lastname: Revicki
authors.affiliation: Leones Group BV, Middenweg 78, Dirkshorn 1746 EB, The Netherlands.
authors.forename: Jaap
authors.initials: J
authors.lastname: van Leeuwen
authors.affiliation: Department of Epidemiology and Biostatistics, The EMGO Institute for Health and Care Research, VU University Medical Center, Van der Boechorststraat 7, Amsterdam 1081, The Netherlands; Amsterdam Rheumatology and Immunology Center, VU University Medical Center, De Boelelaan 1117, Amsterdam 1081 HV, The Netherlands.
authors.forename: Maarten
authors.initials: M
authors.lastname: Boers
authors.affiliation: Department of Rehabilitation Medicine, VU University Medical Center, De Boelelaan 1117, Amsterdam 1081 HV, The Netherlands; Department of Psychiatry, VU University Medical Center, De Boelelaan 1117, Amsterdam 1081 HV, The Netherlands.
authors.forename: Joost
authors.initials: J
authors.lastname: Dekker
authors.affiliation: Amsterdam Rehabilitation Research Center|Reade, Doctor Jan van Breemenstraat 2, Amsterdam 1056 AB, The Netherlands.
authors.forename: Leo D
authors.initials: LD
authors.lastname: Roorda
mesh_terms: D000203:Activities of Daily Living; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001530:Belgium; D059350:Chronic Pain / Q000503:physiopathology*; D003431:Cross-Cultural Comparison; D015444:Exercise; D005163:Factor Analysis, Statistical; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009426:Netherlands; D063868:Patient Outcome Assessment; D011594:Psychometrics; D015203:Reproducibility of Results; D011795:Surveys and Questionnaires / Q000592:standards*; D055815:Young Adult
keywords: Chronic pain; Dutch–Flemish PROMIS; Item response theory; PROMIS; Physical functioning; Psychometrics