Peripheral bone density in patients with rheumatoid arthritis

Bone loss in patients with rheumatoid arthritis (RA) varies at different skeletal sites. The aim of the study was to evaluate whether bone mineral density (BMD) of the forearm is significantly different in patients with RA and controls and may correlate to BMD or other parameters of inflammation or bone resorption. We included 421 patients (357 women: mean age 58.4 ± 12.87 years and 64 men: mean age 56.11 ± 12.80 years) with RA in the study. BMD values of the ultradistal forearm (0.381 ± 0.052 g/cm2) and middistal forearm (0.519 ± 0.091 g/cm2) were significantly (p < 0.01) lower in women with RA than controls (0.395 ± 0.043 and 0.535 ± 0.052 g/cm2, respectively). In contrast, there was no difference in bone density at the lumbar spine (women 0.921 ± 0.l570 g/cm2, men 0.941 ± 0.144 g/cm2) or hip (women 08.11 ± 0.140 g/cm2, men 0.895 ± 0.143 g/cm2) in patients with RA in comparison to controls (lumbar spine: women 0.930 ± 0.146 g/cm2; men 0.960 ± 0.146 g/cm2; hip: women 0.820 ± 0.122 g/cm2; men 0.899 ± 0.144/cm2). Patients with increased inflammatory activity (elevated C-reactive protein) presented with significantly lower BMD of the hip (0.7533 ± 0.144 versus 0.825 ± 0.138 g/cm2) and ultradistal forearm (0.366 ± 0.09 versus 0.390 ± 0.07 g/cm2). This was not the case for the lumbar spine. BMD of the forearm is precise and, in contrast to BMD of the lumbar spine, significantly lower in patients with RA. It is related to inflammatory activity, grip strength, and treatment with glucocorticoids in patients with RA.