Lower Calcium/Phosphorus Ratio is Associated with the Severity of Deformity in Patients with Scoliosis

Objective To explore the association between the serum calcium/phosphorus Ratio and the severity of spinal deformity in scoliosis patients and its clinical significance. Methods Based on retrospective cohort data from 141 non-surgically treated scoliosis patients at Department of Spine Surgery at Guangzhou First People’s Hospital between 2019 and 2025, the Ca/P Ratio and spinal deformity severity were analyzed. Multivariable logistic regression, restricted cubic spline (RCS) analysis, and subgroup analyses were conducted to assess the independent association between the Ca/P Ratio and deformity severity. Adjustments were performed for confounders to improve the validity of the findings. Results Patients in the highest Ca/P Ratio quartile (Q4) exhibited significantly milder spinal deformity (P<0.001). Multivariable analysis demonstrated that each unit increase in the Ca/P Ratio was associated with a reduced risk of severe deformity (OR=0.24, 95% CI: 0.07-0.87, P=0.030). RCS analysis revealed a nonlinear association between the Ca/P Ratio and deformity severity (nonlinear P=0.0495). Subgroup analyses indicated that the protective effect was more pronounced in patients without hypertension/diabetes, males, those with lower BMI, or lower bone mineral density. Conclusion The serum Ca/P Ratio is an independent predictor of spinal deformity severity in scoliosis patients. Its imbalance may exacerbate spinal structural abnormalities by affecting bone metabolism, providing a novel target for metabolic interventions.