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.
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 > or =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.
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.
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 non-vertebral fracture risk.