To assess bone mineral density (BMD) in postmenopausal women with rheumatoid arthritis (RA) and the relative effects of disease activity, disability, and past and current use of corticosteroids.
One hundred ninety-five postmenopausal patients with RA were compared with 597 post-menopausal control subjects. Bone density was measured at the lumbar spine and the proximal femur using dual x-ray absorptiometry. Patients were divided into 3 groups according to corticosteroid use, i.e., never users (61%), current users (21%), and ex-users (18%).
Compared with controls, the never users had no difference in BMD at the lumbar spine, but a 6.9% reduction at the femur (95% confidence interval [95% CI] 3.4-10.3%). In current users (mean daily prednisolone dosage 6.9 mg), BMD was reduced by 6.5% at the spine (95% CI 0-13.0%) and by 7.4% at the hip (95% CI 1.2-13.6%) compared with never users, after adjustment for age, weight, duration of menopause, and functional disability. Mean BMD was similar in the ex-user and never user groups. Results were confirmed in 54 patients who had whole-body BMD measurements. There were inverse correlations between BMD and Health Assessment Questionnaire scores (femoral BMD r = -0.23, P < 0.01; whole-body BMD r = -0.40, P < 0.01) and between BMD and cumulative steroid dose (femoral BMD r = -0.32, P < 0.01; whole-body BMD r = -0.72, P < 0.01).
Osteoporosis in postmenopausal women with RA is more evident at the hip than the spine, and the most important determinants of bone loss are disability and cumulative corticosteroid dose. Low-dose steroids cannot be used with complacency, but recovery after discontinuation of use may be possible.