THE EFFECT OF RHEUMATOID-ARTHRITIS AND STEROID-THERAPY ON BONE-DENSITY IN POSTMENOPAUSAL WOMEN

Objective. 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. Methods. One hundred ninety-five postmenopausal patients with RA were compared with 597 postmenopausal 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%). Results. 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). Conclusion. 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.