Effects of disease and corticosteroids on appendicular bone mass in postmenopausal women with rheumatoid arthritis: comparison with axial measurements.

The potential value of measurements of peripheral bone mass in rheumatoid arthritis (RA) as an assessment of long-term disease activity has recently received renewed attention. This study examines the effects of RA and corticosteroid therapy on newer methods of measuring peripheral bone mass, comparing the results with dual-energy X-ray absorptiometry (DXA) at axial sites. Peripheral quantitative computed tomography of the radius, ultrasound of the calcaneus, and DXA of the hip and spine were compared between 29 controls and 46 women with RA of whom 25 were receiving low-dose corticosteroid therapy. Bone mass was significantly reduced in the RA groups for: (i) radial trabecular (36.1%) and total (15.6%) measurement sites; (ii) calcaneal ultrasound attenuation (31.7%) and velocity (6.6%); and (iii) femoral neck (15.4%) bone mineral density. Lumbar spine and radial cortical measurements were not significantly affected. There were no significant differences between the RA groups. Disease activity and physical activity did appear to be responsible for much of the reduction in bone mass. These results demonstrate that RA is associated with significant bone loss at the hip, radius and calcaneus, but not at the lumbar spine. In this small study, low-dose corticosteroids had little additional deleterious effect.