Health-related quality of life of adult, non-surgically treated patients with idiopathic scoliosis and curves above 45°: a cross-sectional study at an average follow-up of 30 years

Background context: Previous studies on the natural history of moderate to severe idiopathic scoliosis show contradictory results. Some studies reported an increased incidence of back pain and disability in severe curves, while other studies reported no difference in health-related quality of life (HRQoL) compared to age-matched adult controls. None of these studies addressed HRQoL using currently recommended and validated questionnaires. Purpose: To examine the long-term HRQoL in non-surgically treated adult idiopathic scoliosis patients with a curve of 45° or higher. Methods: In this retrospective cohort study, all patients were retrospectively identified in the hospital’s scoliosis database. Patients (1) with idiopathic scoliosis; (2) born before 1981 (to ensure 25-year follow-up after skeletal maturity); (3) with a curve of 45° or more by Cobb's method at the end of growth; and (4) no spinal surgical treatment were selected. Patients received digital questionnaires of the Short Form-36, Scoliosis Research Society-22, Oswestry Disability Index and Numeric Rating Scale. Outcomes of the SF-36 were compared with a national reference cohort. Additional measures with questions regarding choice of education and occupation were used. Results: Forty-eight of 79 (61%) eligible patients completed the questionnaires, at an average follow-up time of 29.9 ± 7.7 years. Their average age was 51.9 ± 8.0, and median Cobb angle at adolescence was 48.5°. Five of the eight SF-36 subdomains were significantly lower in the scoliosis group compared to the nationwide cohort: physical functioning (73 vs 83, p = 0.011), social functioning (75 vs 84, p = 0.022), role physical functioning (63 vs 76, p = 0.002), role emotional functioning (73 vs 82, p = 0.032), and vitality (56 vs 69, p = < 0.001). The scoliosis-specific SRS-22r score of the patients was 3.7 ± 0.7 on a 0–5 scale. The mean NRS score for pain of all patients was 4.9 ± 3.2, and eight patients (17%) reported a NRS of 0 and 31 (65%) a NRS above 3. At the Oswestry Disability Index, 79% of the patients reported minimal disabilities. Thirty-three patients (69%) reported that their scoliosis had influenced their choice of education. Fifteen patients (31%) reported that their scoliosis had influenced their choice of work. Conclusion: Patients with idiopathic scoliosis and curves of 45° or higher have reduced HRQoL. Although many patients experience back pain, the disability reported on the ODI was limited. Scoliosis had noteworthy effect on choice of education.