Association of oxidative stress with clinical characteristics in patients with rheumatoid arthritis

Background Few studies examining the association between oxidative stress and clinical parameters or disease activity in rheumatoid arthritis (RA) patients are available. Therefore, the objective of this study was to test whether oxidative stress has any association with clinical parameters and disease activity in patients with RA. Materials and methods In this post hoc cross-sectional study, 45 RA patients treated with traditional disease-modifying antirheumatic drugs (DMARDs) ± low-dose glucocorticoids ± non-steroidal analgesics for at least 3 months were analyzed. Oxidative stress parameters were malondialdehyde (MDA), superoxide dismutase (SOD), antioxidant potential (AOP) and nonenzymatic superoxide radical scavenger activity (NSSA). Clinical parameters were pain, patient global assessment, physician global assessment, Health Assessment Questionnaire (HAQ), and Disease Activity Score (DAS28). Results Plasma NSSA levels were significantly inversely correlated with tender joints count (r=-0.304; P=0.042), swollen joints count (r=-0.342; p=0.021) and DAS28 (r=-0.396; P=0.009). There were no significant correlations between MDA/SOD/AOP and any of clinical parameters or DAS28 (P>0.05 for all). Multiple regression analysis revealed that NSSA was an independent variable of DAS28 (β=-0.243, P=0.016). Conclusion The preliminary results demonstrate that plasma NSSA levels were inversely correlated with tender and swollen joints count and DAS28 and that NSSA was independently associated with DAS28, in RA patients treated with traditional DMARDs; and provide initial support that NSSA may be used as a biomarker of disease activity in RA patients. This article is protected by copyright. All rights reserved.