ABSTRACT
Objective: To evaluate serum and synovial fluid levels of osteoprotegerin [OPG] in patients with rheumatoid arthritis [RA]; to correlate these values with disease activity variables, radiological bone damage, and DEXA results
Methodology: Twenty female RA patients and ten age-matched healthy female subjects were enrolled in this study. Serum and synovial fluid OPG levels were measured using enzyme-linked immunosorbent assay. Bone status was evaluated using dual x-ray absorptiometry [DEXA] and plain X-ray of the affected joints
Results: RA patients had significantly higher levels of serum OPG than controls [p<0.001]. No significant correlation was found between serum OPG and erythrocyte sedimentation rate, C-reactive protein, rheumatoid factor and disease duration [p>0.05]. OPG serum levels were positively correlated with age in both groups [p<0.001]. A significant difference in serum OPG level was found between patients with and without erosions [p=0.008]. RA patients had significantly lower BMD values than controls [p< 0.05]. There was a highly significant correlation between serum OPG level and BMD values [p<0.001]. Mean synovial fluid. OPG level was higher than serum OPG level obtained from the same patient, but with no statistical significance [p>0.05]
Conclusion: Bone loss in RA patients is associated with higher serum and synovial fluid levels of OPG than in healthy subjects, which might be the result of a compensatory production of OPG, yet there was lack of compensatory age-related increase of OPG serum levels