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.