Estimating SRS-22 quality of life measures with SF-36 - Application in idiopathic scoliosis

Study Design. Comparison of a generic-with a disorder-specific health- related quality of life (HRQL) questionnaire. Objectives. To determine the association between generic- and disorder-specific questionnaire domains of similar construct. Summary of Background Data. Short Form-36 (SF-36), a general HRQL questionnaire, has been widely used to evaluate patients with scoliosis and related spine deformity. How it relates to the disorder-specific Scoliosis Research Society-22 (SRS-22) questionnaire is currently unknown. Methods. Seventy-eight patients, operated at a mean age 14.5 years for idiopathic scoliosis with a mean largest Cobb of 60 degrees, completed both questionnaires at a mean of 9.25 years after surgery. Results. The predictability of the SRS-22 Mental Health domain is excellent using the SF- 36 Mental Health domain, from which it was adapted (R-2 = 0.81). The SRS-22 Pain domain predictability using the SF-36 Bodily Pain domain is also excellent (R-2 = 0.79). The SRS-22 Function domain predictability using the SF-36 Physical Component Summary domain is good (R-2 = 0.64). The SRS-22 Self- Image and Management Satisfaction/ Dissatisfaction domains are poorly predicted by the SF-36 General Health and Physical Component Summary domains, respectively, R-2 = 0.52 and 0.54. Conclusion. SRS-22 Mental Health and Pain domain scores can be accurately calculated from correlating SF-36 domain scores. SRS-22 Function scores can be fairly well predicted from correlated SF-36 domain scores. Self- Image and Management Satisfaction/Dissatisfaction domain scores cannot be approximated from SF-36 domain scores.