title: Validation of a minimum outcome core set in the evaluation of patients with back pain.
abstract: METHODS
  Prospective study of patients with subacute osteoporotic fracture (SOF) or chronic low back pain (CLBP).
  
  
  OBJECTIVE
  To evaluate reliability, validity, and responsiveness of a purposefully brief outcome instrument.
  
  
  BACKGROUND
  A minimum standardized "core set" was proposed for monitoring patients with low back pain in 1998, but an assessment of metric properties was still lacking.
  
  
  METHODS
  The Core Set, SF-36, and Oswestry questionnaires were completed by 154 patients. Test-retest reproducibility was evaluated in a subsample of 43 stable patients with CLBP. Responsiveness was evaluated by estimating effect size (ES) of pre-postsurgery changes in 50 patients with SOF and 23 with CLBP.
  
  
  RESULTS
  The total Core Set showed good reproducibility with intraclass correlation coefficients on test-retest near the highest standard of 0.9, whereas internal consistency differed between patients with CLBP and those with SOF (Cronbach's alpha of 0.92 and 0.64, respectively). Most correlations of the Core Set with SF-36 and Oswestry, previously hypothesized as high, were >0.65, demonstrating good construct validity. Sensitivity to change of the Core Set (ES 0.4-2.3) is similar to the Oswestry (ES 0.7 and 2.3).
  
  
  CONCLUSIONS
  These findings support the potential usefulness of the Core Set when respondent burden is a major concern. However, subscale scores need to be further tested in other populations before they can be widely recommended.
authors.affiliation: Health Services Research Unit, Institut Municipal d'Investigació Mèdica (IMIM-IMAS), Barcelona, Spain.
authors.forename: Montserrat
authors.initials: M
authors.lastname: Ferrer
authors.forename: Ferran
authors.initials: F
authors.lastname: Pellisé
authors.forename: Oscar
authors.initials: O
authors.lastname: Escudero
authors.forename: Luis
authors.initials: L
authors.lastname: Alvarez
authors.forename: Angels
authors.initials: A
authors.lastname: Pont
authors.forename: Jordi
authors.initials: J
authors.lastname: Alonso
authors.forename: Richard
authors.initials: R
authors.lastname: Deyo
mesh_terms: D000328:Adult; D000368:Aged; D001416:Back Pain / Q000503:physiopathology* / Q000628:therapy*; D002908:Chronic Disease; D005260:Female; D050723:Fractures, Bone / Q000209:etiology / Q000503:physiopathology* / Q000628:therapy*; D006801:Humans; D008297:Male; D008875:Middle Aged; D010024:Osteoporosis / Q000150:complications*; D017063:Outcome Assessment, Health Care / Q000379:methods* / Q000592:standards; D015203:Reproducibility of Results; D011795:Surveys and Questionnaires / Q000592:standards*