The reliability and concurrent validity of the Scoliosis Research Society-22 patient questionnaire for idiopathic scoliosis

Study Design. Outcome study to determine response distribution, internal consistency, reproducibility, and concurrent validity of the Scoliosis Research Society-22 (SRS-22) health-related quality-of-life (HRQL) questionnaire. Objectives. Further refinement of an HRQL questionnaire specific for idiopathic scoliosis. Summary of Background Data. Previous experience with the original and modified SRS HRQL questionnaires suggested a need for further refinement and more complete validation. Methods. The SRS-22 and Short Form 36 (SF-36) HRQL questionnaires were mailed to 83 previously surveyed postoperative idiopathic scoliosis patients. Results. Fifty-eight (70%) patients returned the first set of questionnaires. Their average age at surgery was 14.6 years, and their average follow-up interval since surgery was 10.8 years. Fifty-one (88%) of the 58 returned the second set of questionnaires an average of 28 days later. The psychometric attributes of the instruments were comparable: score distribution, SRS-22 56.9% ceiling and 1.7% floor, SF-36 79.3% ceiling and 1.7% floor; internal consistency (Cronbach alpha), SRS-22 0.92 to 0.75, SF-36 0.91 to 0.36; and reproducibility (intraclass correlation coefficient), SRS-22 0.96 to 0.85, SF-36 0.92 to 0.61. Concurrent validity, determined by Pearson Correlation Coefficients between SRS-22 and SF-36 domains, was 0.70 or greater (P<0.0001) for 17 relevant comparisons. Conclusion. The SRS-22 HRQL questionnaire is reliable with internal consistency and reproducibility comparable to SF-36. In addition, it demonstrated concurrent validity when compared to SF-36. It is shorter and more focused on the health issues related to idiopathic scoliosis than SF-36.