Reliability and Validity Testing of a Danish Translated Version of the Scoliosis Research Society Instrument-22 Revised (SRS-22R)

Abstract

Study design: Cross-sectional Objectives: To present a reliable and valid Danish translation of the Scoliosis Research Society-22R (SRS-22R).

Summary of background data: The SRS22R was designed as a disease-specific measure of quality of life in surgically treated adolescent idiopathic scoliosis (AIS) patients. It has been translated and adapted into several languages. A reliable and valid Danish version is not available.

Methods: A Danish version of the SRS-22R was developed using previously published and widely accepted guidelines. The final Danish SRS-22R and the Danish Short Form-36 were administered to 169 AIS patients and 45 healthy controls. Cronbach's α was computed as a measure of internal consistency. Concordant validity was determined by computing correlations of the SRS-22R Domains with the corresponding SF-36 domains and factor analysis. Discriminant validity was determined by comparing Domain scores between AIS patients treated surgically, AIS patients treated with a brace, and the healthy controls.

Results: One hundred sixty-five (97.6%) AIS patients and 42 (93.3%) healthy controls returned their questionnaires. Moderate ceiling effects were observed in the AIS cohort for the Function and Satisfaction Domains. Cronbach's α for each Domain and the Total score were good to excellent. Pearson correlation coefficients were found to be high for the SRS-22R Domains that had similar latent variables as the SF-36 Domains. Factor analysis revealed an underlying factorial structure of the questionnaire accounting for 60% of the explained variance. The SRS-22R Domain scores were statistically significantly different between the AIS cohort that had surgery, the AIS cohort that was treated with a brace, and the healthy controls.

Conclusions: The Danish version of the SRS-22R is reliable, with content, concordant, and discriminant validity. The scores, the score distribution, and the ceiling and floor effects were similar to those of the original SRS-22R in English as well as other previous translations.

Keywords: Adolescent idiopathic scoliosis; Outcomes; Reliability study; Scoliosis Research Society Questionaire 22R; Validation.