Correlation between osteoporosis and bone erosionin in patients with early rheumatoid arthritis

Objective To investigate the characteristics of osteoporosis(OP) and bone erosion in patients with early rheumatoidarthritis(RA). Methods A total of 427 patients with RA(including 139 early RA with disease duration less than 1 year and 288 non-early RA ).BMD of proximal femur and lumbar vertebrae were measured by dual energy X-ray absorptiometry(DEXA).The assessment of bone erosion by examination of hands X-ray in all early RA patients,meanwhile,clinical index and the treatment with glucocorticoid(GC) were recorded.Data of 158 normal people were collected as control group. Results The prevalence of OP in early RA and non-early RA were 23.5%,35.4%,while in control group was 13.9%(χ²=24.84,P＜0.001).BMD sat different positions were decreased in all three groups(P＜0.05).In the early RA,patients with OP had elder age as compared with the group without OP(P＜0.05).There were no significant difference regarding the use of GC,RF,ESR,CRP and DAS28 scores between OP group and non-OP gorup(P＞0.05).The BMD of total femoral area and lumbar spine were negatively correlated with the X-ray stage(P＜0.05).The BMD of L₂ and L_2~4 were also negatively correlated with anti-CCP(P＜0.05).The percentage of bone erosion was 13.7%,which was lower than that of OP(χ²=4.18，P=0.041) in the early RA.The average disease duration of early RA patients with OP was shorter than that in early RA patients with bone erosion(0.59±0.35 yr vs. 0.82±0.29 yr,t=2.46,P=0.018). Conclusion The patients with early RA show obvious OP which occurs earlier than bone erosion,and the incidence of OP is higher than bone erosion.We should pay more attentions to the occurrence of OP in early RA.