Osteoporosis is a well-known extra-articular phenomenon in patients with uncontrolled, long-standing rheumatoid arthritis (RA). In the present study, the extent of osteoporosis and reduced bone mineral density (BMD) and the disease-related and demographic factors that are associated with osteoporosis and reduced BMD were examined in patients with recently diagnosed, active RA.
BMD of the total hip and the lumbar spine was measured using dual-energy x ray absorptiometry in 381 patients with recently diagnosed active RA, who had never been treated with DMARDs or corticosteroids. Osteoporosis was defined as a T score <or=-2.5 SD and reduced BMD as Z score <or=-1 SD. Multivariate logistic regression analyses were performed to detect associations of osteoporosis and reduced BMD with disease activity, functional disability, joint damage (Sharp-van der Heijde score) and demographic factors.
Osteoporosis and reduced BMD were found in the spine and/or the hip in 11% and 25%, respectively, of the patients. Longer symptom duration and presence of rheumatoid factor (RF) were the only RA-specific markers for osteoporosis and reduced BMD. Further, postmenopausal status in women, a low body mass index, familial osteoporosis, and, remarkably, male gender, were independently associated with osteoporosis and reduced BMD.
In patients with recently diagnosed active RA who had never been treated with DMARDs or corticosteroids, BMD seems to be well-preserved and predominantly related to demographic factors. Longer symptom duration and a positive RF, but not higher disease activity or more joint damage, were related to osteoporosis and reduced BMD.