Reliability and validity of an adapted Thai version of the Scoliosis Research Society-22 questionnaire

PURPOSE: The Scoliosis Research Society-22 (SRS-22) questionnaire is a widely accepted questionnaire used to assess the health-related quality of life for scoliosis patients in the United States. However, its adaptation in other languages is necessary for its multinational use. A cross-sectional study was performed to evaluate the validity and reliability of an adapted Thai version of the SRS-22 questionnaire. METHODS: An expert committee performed translation/retranslation of the English version of the SRS-22 questionnaire, as well as a cross-cultural adaptation process. Later, SRS-22 questionnaires and previously validated Short Form-36 version 2 (SF-36v2) outcome instruments were given to patients treated for idiopathic scoliosis with a minimum of 1 year of follow-up. Internal consistency and reproducibility were determined by Cronbach’s alpha statistics and the intraclass correlation coefficient, respectively. Concurrent validity was measured by comparing SRS-22 results with a previously validated questionnaire (SF-36v2). Measurement was made using the Pearson correlation coefficient (r). RESULTS: The study showed satisfactory internal consistency with Cronbach’s alpha values for all of the corresponding domains (pain, 0.72; self-image/appearance, 0.87; mental health, 0.83; satisfaction with management, 0.63; and function/activity, 0.83). The test–retest reproducibility was also excellent or good for all domains (pain, 0.72; self-image/appearance, 0.85; mental health, 0.82; satisfaction, 0.62; and function/activity, 0.81). For concurrent validity, excellent correlation was found in two domains, good in six domains, moderate in five domains, and poor in five domains of the 18 relevant domains. CONCLUSIONS: The Thai version of the SRS-22 outcome instrument has satisfactory internal consistency, excellent reproducibility, and acceptable validity.