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Discriminative and Predictive Validity of the Scoliosis Research Society-22 Questionnaire in Management and Curve-Severity Subgroups of Adolescents With Idiopathic Scoliosis

Parent, Eric C. PhD*†; Hill, Doug MBA; Mahood, Jim MD; Moreau, Marc MD; Raso, Jim MASc; Lou, Edmond PhD

doi: 10.1097/BRS.0b013e3181af28bf
Health Services Research

Study Design. 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.

Summary of Background Data. 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°, 30°–50°, and >50°). 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° than with Cobb angles of 30° to 50°. Self-image and total scores were worse for those with Cobb angles of >50° 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°.

Conclusion. 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.

The Scoliosis Research Society-22 pain, self-image, and satisfaction domains discriminated among 4 management subgroups of females with idiopathic scoliosis. All scores except satisfaction discriminated among 3 curve-severity subgroups. Self-image scores accurately classified 54% of subjects from 3 curve-severity categories. Self-image scores also accurately classified 73% of subjects with curves above or below 50°.

From the *University of Alberta, Edmonton, Alberta, Canada; and †Glenrose Rehabilitation Hospital, Edmonton, Alberta, Canada.

Acknowledgment date: May 8, 2006. First revision date: March 17, 2008. Second revision date: January 8, 2009. Third revision date: March 24, 2009. Acceptance date: March 25, 2009.

The manuscript submitted does not contain information about medical device(s)/drug(s).

Foundation funds were received in support of this work. No benefits in any form have been or will be received from a commercial party related directly or indirectly to the subject of this manuscript.

Supported by the Edmonton Orthopedic Research Society.

Address correspondence and reprint requests to Eric C. Parent, PhD, Department of Physical Therapy, University of Alberta, 2–50 Corbett Hall, Edmonton, Alberta, Canada T6G 2G4; E-mail:

© 2009 Lippincott Williams & Wilkins, Inc.