Impact of radiologic variables on item responses of ODI, SRS22 and SF-36. in adult spinal deformity patients: differential item functioning (DIF) analysis results from a multi-center database

• Published in: European spine journal 2022-05, Vol.31 (5), p.1166-1173
• Main Authors: Kieser, D. C., Yuksel, S., Boissiere, L., Yilgor, C., Cawley, D. T., Hayashi, K., Alanay, A., Kleinstueck, F. S., Pellise, F., Perez-Grueso, F. J. S., Jean-Marc, Vital, Bourghli, A., Acaroglu, E. R., Obeid, I.
• Format: Article
• Language: English
• Subjects: Adult; Aged; Back surgery; Databases, Factual; Disability Evaluation; Female; Hospitals; Humans; Medicine; Medicine & Public Health; Mental health; Middle Aged; Neurosurgery; Original Article; Pain; Patients; Quality of Life; Retrospective Studies; Scoliosis; Scoliosis - diagnostic imaging; Scoliosis - surgery; Self image; Surgical Orthopedics; Surveys and Questionnaires; Treatment Outcome; Variables
• ISSN: 0940-6719; 1432-0932
• DOI: 10.1007/s00586-021-07088-5

Purpose To determine if responses given to each question of the Scoliosis Research Society-22 (SRS22), Oswestry disability index (ODI) and Short Form-36 (SF-36) questionnaires are influenced by the radiological parameters. Methods Patients enrolled in a multi-centre prospectively collected adult spinal deformity database who had complete SRS22, ODI and SF-36 data at baseline and at one-year follow-up were analysed. The presence of a differential item function of each question within each score in relation to radiological parameters was analysed using a mixed Rasch model with the radiological threshold value(s) determined. Results Of those patients analysed ( n  = 1745; 1406 female, average age 51.0 ± 19.8 years), 944 were surgically and 801 were non-surgically treated. For the SRS22, questions ( Q ) 3, 5 and 18 were sensitive to almost all radiological parameters and the overall score was found sensitive to the Cobb angle. For the ODI, Q3, 6, 9 and 10 were not sensitive to any radiologic parameters whereas Q4 and 5 were sensitive to most. In contrast, only 3 of the SF-36 items were sensitive to radiological parameters. Conclusions 78% of the SRS-22, 60% of the ODI and 8% of the questions in the SF-36 are sensitive to radiological parameters. Sagittal imbalance is independently associated with a poor overall outcome, but affects mental status and function more than pain and self-image. The assembly of questions responsive to radiological parameters may be useful in establishing a connection between changes in radiologic parameters and HRQL.