BMD-erosions correlation in RA: Potential for bone-directed treatments?

Hip bone mineral density (BMD) correlates with erosion scores in postmenopausal women who have rheumatoid arthritis (RA), although the relationship is not statistically significant after adjustment for clinical factors. BMD and erosions appear to be more strongly correlated in patients with early RA.

Solomon and coworkers studied 163 postmenopausal women being treated for RA but not for osteoporosis. Study participants underwent dual-energy x-ray absorptiometry of the hip and spine, as well as hand radiographs, and they completed a questionnaire.

The erosion score correlated significantly with total hip BMD but not with spine BMD. Study participants who were positive for rheumatoid factor (RF) (63%) had significantly lower hip BMD than those who were RF negative; however, spine BMD appeared to bear no relationship to RF status. After controlling for variables (eg, age, body mass index, and cumulative dose of oral corticosteroids), the relationship between BMD and focal erosions vanished.

The authors noted that an association between erosions and BMD may be most relevant for patients with severe or early unmanaged RA and that recognizing it probably will increase in importance as more bone-directed treatments become part of RA management (eg, managing multiple skeletal manifestations of RA with a single agent).