Mid-thoracic predominance and region-specific risk factors for vertebral fractures in rheumatoid arthritis: a cross-sectional study

INTRODUCTION/OBJECTIVES: Vertebral fractures are common in rheumatoid arthritis (RA), but whether their risk factors differ by spinal region remains unclear. This study aimed to identify region-specific risk factors for vertebral fractures in RA, particularly in the mid-thoracic spine and thoracolumbar junction, and to describe fracture distribution. METHODS: We retrospectively evaluated 93 patients with RA and 108 knee osteoarthritis controls. Clinical, laboratory, and bone quality markers were collected. Vertebral fractures were identified on spinal radiographs using AI-assisted software with physician confirmation. Multivariable logistic regression was used to identify risk factors. RESULTS: Vertebral fractures were more common in RA than in controls (32.3% vs. 12.0%) and clustered in the mid-thoracic region (T4-T10). Overall vertebral fractures were associated with older age, higher cumulative glucocorticoid exposure, and absence of biologic or targeted synthetic disease-modifying antirheumatic drug (b/tsDMARD) therapy. In region-specific analyses, mid-thoracic fractures were independently associated with age (odds ratio (OR) 1.10, 95% confidence interval (CI) 1.03-1.19) and serum pentosidine levels (OR 17.32, 95% CI 1.49-273.04). Thoracolumbar junction fractures were associated with age (OR 1.12, 95% CI 1.03-1.25), b/tsDMARD use (OR 0.11, 95% CI 0.01-0.74), DAS28-CRP (OR 2.30, 95% CI 1.14-5.08), and cumulative glucocorticoid exposure (OR 1.09, 95% CI 1.02-1.18). CONCLUSIONS: Vertebral fractures in RA show distinct region-specific risk profiles. Mid-thoracic fractures were associated mainly with impaired bone quality, whereas thoracolumbar junction fractures were more strongly related to disease severity and glucocorticoid exposure. These findings support region-specific fracture assessment and prevention strategies in RA. Key Points • Vertebral fractures in rheumatoid arthritis (RA) showed a characteristic predominance in the mid-thoracic spine. • Distinct region-specific risk profiles were identified, with mid-thoracic fractures associated with older age and bone quality-related impairment reflected by higher serum pentosidine levels. • Thoracolumbar junction fractures were more strongly associated with RA disease activity and cumulative glucocorticoid exposure. • Region-specific assessment may help identify different mechanisms of vertebral fragility and guide targeted prevention strategies in rheumatoid arthritis.