CONCISE REPORT Hand cortical bone mass and its associations with radiographic joint damage and fractures in 50–70 year old female patients with rheumatoid arthritis: cross sectional Oslo-Truro-Amsterdam (OSTRA) collaborative study

Objective: To investigate the relationship between hand bone mineral density (BMD) and radiographic joint damage, and between hand BMD and fractures in 50–70 year old women with longstanding RA. Methods: Demographic, clinical data, and imaging data on hand radiographs and Genants vertebral deformity score on spine radiographs were collected from 135 women with RA of >5 years, recruited from three European rheumatology clinics. Metacarpal hand BMD was measured by digital hand x ray radiogrammetry (DXR), and hip and lumbar spine BMD by dual x ray absorptiometry (DXA). Multiple regression analyses were used to examine associations between hand BMD and radiographic joint damage, and hand BMD and fractures. Results: Hand BMD was strongly and independently associated with radiographic hand joint damage in a linear regression model adjusted for age, centre, BMI, disease duration, RF, 18 deformed joint count, ESR, and femoral neck BMD. In a multivariate logistic regression model adjusted for relevant variables, hand BMD and femoral neck BMD, but not spine BMD, were independently associated with vertebral deformities and with non-vertebral fractures. Conclusion: BMD measured by DXR on conventional hand radiographs in patients with RA may potentially be used as an indicator of joint damage and of vertebral and nonvertebral fracture risk.