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

Abstract

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 (R2 = 0.81). The SRS-22 Pain domain predictability using the SF-36 Bodily Pain domain is also excellent (R2 = 0.79). The SRS-22 Function domain predictability using the SF-36 Physical Component Summary domain is good (R2 = 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, R2 = 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.