The impact of osteoporosis on preoperative presentation in adult spinal deformity patients undergoing surgical correction: a retrospective study.

PURPOSE: Osteoporosis is common in adults with spinal deformity (ASD) and may worsen baseline malalignment and disability. Because these conditions often coexist, understanding how osteoporosis and patients meeting criteria for high risk of osteoporosis affect deformity severity and quality of life is key to improving outcomes.

METHODS

Adults (≥ 18 years) undergoing ASD surgery with complete baseline and two-year follow-up data were stratified into osteoporosis, high-risk, and non-osteoporotic cohorts. Osteoporosis was defined by preexisting diagnosis; high-risk by American Association of Clinical Endocrinologists (AACE) criteria (female ≥ 65 years or risk factors: steroids, chronic kidney disease, alcohol use, vitamin D deficiency, limited mobility, diabetes). Non-osteoporotic patients had normal bone quality. Baseline alignment was evaluated using Global Alignment and Proportionality (GAP) and Sagittal Age-Adjusted Score (SAAS). Health-related quality of life (HRQoL) was analyzed using multivariable regression adjusted for age, BMI, Charlson Comorbidity Index (CCI), and modified Fragility Index (mFI).

RESULTS

Among 899 patients (mean age 60.3 ± 15.0 years; 74% female; BMI 27.5 ± 5.8 kg/m2; CCI 1.7 ± 1.7), 165 (18.4%) were osteoporotic, 194 (21.6%) high-risk, and 540 (60.1%) non-osteoporotic. Notably, 54% meeting AACE criteria lacked a formal osteoporosis diagnosis. Osteoporotic patients were more often severely frail (24.8% vs. 11.7%). After adjusting for confounders, osteoporosis/high-risk patients were less likely SAAS-matched (OR 0.646) and GAP-proportioned (OR 0.485) at baseline. Adjusted for baseline alignment, they were also more likely to be severely disabled (Oswestry Disability Index > 60; OR 1.45).

CONCLUSION

ASD patients with osteoporosis or high-risk features exhibit poorer quality of life and more severe deformity at baseline, as inadequate bone health remains independently associated with worse radiographic alignment and greater disability after adjustment for confounders.