title: Discriminative and predictive validity of the scoliosis research society-22 questionnaire in management and curve-severity subgroups of adolescents with idiopathic scoliosis.
abstract: METHODS
  Prospective cross-sectional measurement study.
  
  
  OBJECTIVE
  To determine the ability of the Scoliosis Research Society (SRS)-22 questionnaire to discriminate among management and scoliosis severity subgroups and to correlate with internal and external measures of curve severity.
  
  
  BACKGROUND
  In earlier studies of the SRS-22 discriminative ability, age was not a controlled factor. The ability of the SRS-22 to predict curve severity has not been thoroughly examined.
  
  
  METHODS
  The SRS-22 was completed by 227 females with adolescent idiopathic scoliosis. Using Analysis of covariance analyses controlling for age, the SRS-22 scores were compared among management subgroups (observation, brace, presurgery, and postsurgery) and curve-severity subgroups (in nonoperated subjects: Cobb angles of <30 degrees, 30 degrees -50 degrees, and >50 degrees). A stepwise discriminant analysis was used to identify the SRS-22 domains most discriminative for curve-severity categories. Correlation between SRS-22 scores and radiographic or surface topography measurements was used to determine the predictive ability of the questionnaire.
  
  
  RESULTS
  Pain was better for subjects treated with braces than for those planning surgery. Self-image was better for subjects under observation or postsurgery than for those planning surgery. Satisfaction was better for the brace and postsurgery subgroups than for the observation or presurgery subgroups. Statistically significant mean differences between subgroups were all larger than 0.5, which is within the range of minimal clinically important differences recommended for each of the 5-point SRS-22 domain scoring scales. Pain and mental health were worse for those with Cobb angles of >50 degrees than with Cobb angles of 30 degrees to 50 degrees. Self-image and total scores were worse for those with Cobb angles of >50 degrees than both other subgroups. Using discriminant analysis, self-image was the only SRS-22 domain score selected to classify subjects within curve severity subgroups. The percentage of patients accurately classified was 54% when trying to classify within 3 curve severity subgroups. The percentage of patients accurately classified was 73% when classifying simply as those with curves larger or smaller than 50 degrees .
  
  
  CONCLUSIONS
  Pain, self-image, and satisfaction scores could discriminate among management subgroups, but function, mental health and total scores could not. The total score and all domain scores except satisfaction discriminated among curve-severity subgroups. Using discriminant analysis, self-image was the only domain retained in a model predicting curve-severity categories.
authors.affiliation: University of Alberta, Edmonton, Alberta, Canada. eparent@ualberta.ca
authors.forename: Eric C
authors.initials: EC
authors.lastname: Parent
authors.forename: Doug
authors.initials: D
authors.lastname: Hill
authors.forename: Jim
authors.initials: J
authors.lastname: Mahood
authors.forename: Marc
authors.initials: M
authors.lastname: Moreau
authors.forename: Jim
authors.initials: J
authors.lastname: Raso
authors.forename: Edmond
authors.initials: E
authors.lastname: Lou
mesh_terms: D000293:Adolescent; D001416:Back Pain / Q000175:diagnosis / Q000209:etiology / Q000628:therapy; D001915:Braces / Q000706:statistics & numerical data; D002648:Child; D003430:Cross-Sectional Studies; D004185:Disability Evaluation; D016002:Discriminant Analysis; D005260:Female; D006801:Humans; D008603:Mental Health / Q000706:statistics & numerical data; D015233:Models, Statistical; D017060:Patient Satisfaction; D011237:Predictive Value of Tests; D011446:Prospective Studies; D011859:Radiography; D015203:Reproducibility of Results; D012600:Scoliosis / Q000145:classification / Q000175:diagnosis* / Q000628:therapy*; D012649:Self Concept; D012647:Self-Assessment; D012680:Sensitivity and Specificity; D012720:Severity of Illness Index; D013123:Spinal Fusion / Q000706:statistics & numerical data; D011795:Surveys and Questionnaires; D055815:Young Adult