Bone mineral density in patients with rheumatoid arthritis: relation between disease severity and low bone mineral density

Objective: To examine variables associated with bone mineral density (BMD) in patients with rheumatoid arthritis (RA). Methods: We investigated 373 patients with low to moderately active RA. Patients with low disease activity were recruited from a cohort of patients in clinical remission. Patients with moderately active disease were included in a trial comparing the effects of long term high intensity exercise programme and conventional physical therapy. Demographic and clinical data were collected. Bone mineral density (BMD) was measured by means of dual x ray absorptiometry (DXA). Associations between demographic and clinical measurements on the one hand and BMD on the other were investigated in regression analyses. Results: The patient group consisted of middle aged, mainly female, patients. The median (interquartile range) disease duration was 7 (4 to 13) years, the mean disease activity score (standard deviation) was 3.2 (1.4). Of the group, 66% was rheumatoid factor positive, and 83% (n = 304) had never used corticosteroids. The median Larsen score of hands and feet was 27 (5 to 61). Greater age and low body mass index were related to low BMD at the hip and spine. High Larsen score for hands and feet was significantly associated with low BMD at the hip. The use of corticosteroids was not independently associated with BMD. The results of the multiple regression analyses also applied to the subgroup of corticosteroid naive patients. Conclusion: BMD data of patients with low to moderately active RA demonstrated an association between high radiological RA damage and low BMD at the hip, which suggests an association between the severity of RA and the risk of generalised bone loss, which also occurred in corticosteroid naive patients.