title: Validity, Reliability, and Responsiveness of SRS-7 as an Outcomes Assessment Instrument for Operatively Treated Patients With Adult Spinal Deformity.
abstract: METHODS
  A retrospective analysis.
  
  
  OBJECTIVE
  The aim of our study was to compare the normality, concurrent validity, internal consistency, responsiveness, and dimensionality of an item response theory-derived seven-question instrument (SRS-7), against the Scoliosis Research Society-22r (SRS-22r) questionnaire in operatively treated patients with adult spinal deformity (ASD).
  
  
  BACKGROUND
  Compared with SRS-22r, SRS-7 (which has been validated in operatively treated patients with adolescent idiopathic scoliosis) has advantages of being short, unidimensional, and linear.
  
  
  METHODS
  A prospective database of ASD patients was queried for patients 18 years or older who were operatively treated, and who answered pre- and postoperative (at 2-year follow-up) SRS-22r questions (n = 276). Corresponding SRS-7 scores were calculated using answers to SRS-22r items 1, 4, 6, 10, 18, 19, and 20. Significance was set at a P value less than 0.01.
  
  
  RESULTS
  SRS-7 and SRS-22r were normally distributed preoperatively but not postoperatively. SRS-7 and SRS-22r scores had high correlation both preoperatively (r = 0.76, P < 0.01) and postoperatively (r = 0.83, P < 0.01). The internal consistency reliability Cronbach α values were 0.61 (SRS-7) and 0.83 (SRS-22r) preoperatively and 0.91 (SRS-7) and 0.95 (SRS-22r) postoperatively. SRS-7 was found to be more responsive than SRS-22r with measures of effect size: Cohen d = 1.21 versus 1.13, Hedge g = 1.21 versus 1.13, and effect size correlation r = 0.52 versus 0.49. Iterative principal factor analysis of pre- and postoperative scores showed the presence of one dominant latent factor in SRS-7 (unidimensionality) and four latent factors in SRS-22r (multidimensionality).
  
  
  CONCLUSIONS
  SRS-7 is a valid, reliable, responsive, and unidimensional instrument, which can be used as a short-form alternative to the SRS-22r for assessing global changes in patient-reported outcomes over time in patients with ASD.
  
  
  METHODS
  3.
authors.affiliation: Department of Orthopaedic Surgery, The Johns Hopkins University, Baltimore, MD.
authors.forename: Amit
authors.initials: A
authors.lastname: Jain
authors.affiliation: Department of Orthopaedic Surgery, Hospital for Special Surgery, New York, NY.
authors.forename: Virginie
authors.initials: V
authors.lastname: Lafage
authors.affiliation: Department of Orthopaedic Surgery, Washington University, St. Louis, MO.
authors.forename: Michael P
authors.initials: MP
authors.lastname: Kelly
authors.affiliation: Department of Orthopaedic Surgery, University of Virginia, Charlottesville, VA.
authors.forename: Hamid
authors.initials: H
authors.lastname: Hassanzadeh
authors.affiliation: Department of Orthopaedic Surgery, The Johns Hopkins University, Baltimore, MD.
authors.forename: Brian J
authors.initials: BJ
authors.lastname: Neuman
authors.affiliation: Department of Neurosurgery, The Johns Hopkins University, Baltimore, MD.
authors.forename: Daniel M
authors.initials: DM
authors.lastname: Sciubba
authors.affiliation: Rocky Mountain Scoliosis and Spine, Rocky Mountain Hospital for Children and Presbyterian St. Luke's Medical Center, Denver, CO.
authors.forename: Shay
authors.initials: S
authors.lastname: Bess
authors.affiliation: University of Virginia Health System, Charlottesville, VA.
authors.forename: Christopher I
authors.initials: CI
authors.lastname: Shaffrey
authors.affiliation: University of California San Francisco, San Francisco, CA.
authors.forename: Christopher P
authors.initials: CP
authors.lastname: Ames
authors.affiliation: University of California San Diego, San Diego, CA.
authors.forename: Justin K
authors.initials: JK
authors.lastname: Scheer
authors.affiliation: Department of Orthopaedic Surgery, University of Kansas, Kansas City, KS.
authors.forename: Douglas
authors.initials: D
authors.lastname: Burton
authors.affiliation: Department of Orthopedics, Washington University, St. Louis, MO.
authors.forename: Munish C
authors.initials: MC
authors.lastname: Gupta
authors.affiliation: Department of Orthopaedic Surgery, Oregon Health and Science University, Portland, OR.
authors.forename: Robert
authors.initials: R
authors.lastname: Hart
authors.affiliation: Southwest Scoliosis Institute, Plano, TX.
authors.forename: Richard A
authors.initials: RA
authors.lastname: Hostin
authors.affiliation: Department of Orthopaedic Surgery, The Johns Hopkins University, Baltimore, MD.
authors.forename: Khaled M
authors.initials: KM
authors.lastname: Kebaish
mesh_terms: D000328:Adult; D000368:Aged; D016208:Databases, Factual; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D017063:Outcome Assessment, Health Care / Q000379:methods*; D011446:Prospective Studies; D012042:Registries; D015203:Reproducibility of Results; D012600:Scoliosis / Q000601:surgery*; D016896:Treatment Outcome