Validity and Reliability of an Adapted German Version of Scoliosis Research Society-22 Questionnaire

Abstract

Study to determine the internal consistency and validity of adapted German version of Scoliosis Research Society-22 (SRS-22) questionnaire. To evaluate the validity and reliability of adapted German version of SRS-22 questionnaire. The SRS-22 questionnaire was developed to assess the health-related quality of life for English-speaking patients with idiopathic scoliosis. For scientific purpose and standardized comparison of outcome studies for the treatment of idiopathic scoliosis its adaptation into German is necessary to respect cultural and lingual differences. Translation/retranslation of the English version of the SRS-22 was conducted, and all steps for cross-cultural adaptation process were performed. Thus, SRS-22 questionnaire and previously validated Roland-Morris score were mailed to 222 patients who had been treated surgically or conservatively for idiopathic scoliosis. Seventy-eight patients (35%) responded to the first set of questionnaires and 54 of the first time responder returned their second survey. The median age of all patients who joined the study was 19 years. Measures of reliability namely, selectivity, internal consistency, and reproducibility were determined by Cronbach's alpha statistics and intraclass correlation coefficient, respectively. Concurrent validity was measured by comparing with an already validated questionnaire (Roland-Morris score). Measurement was made using the Spearman correlation coefficient. The study demonstrated satisfactory internal consistency with high Cronbach's alpha values for 4 of the corresponding domains (pain, 0.75; self-image, 0.84; mental health, 0.88; and satisfaction, 0.61). However, the Cronbach's alpha value for function/activity domain (0.67) was considerably lower than the original English questionnaire. For the same domains intraclass correlation coefficient demonstrating satisfactory test/retest reproducibility. The adapted German version of the SRS-22 questionnaire can be used to assess the outcome of treatment for German-speaking patients with idiopathic scoliosis.