Serum levels of reactive oxygen metabolites at 12 weeks during tocilizumab therapy are predictive of 52 weeks-disease activity score-remission in patients with rheumatoid arthritis

Abstract Background To verify whether serum levels of reactive oxygen metabolites (ROM) are predictive of future clinical remission in patients with rheumatoid arthritis (RA) receiving tocilizumab (TCZ) therapy. Methods A total of 46 patients with RA receiving TCZ therapy were enrolled in this study. Patients were divided into remission and non-remission groups based on disease activity score 28 (DAS28)-erythrocyte sedimentation rate (ESR) or clinical disease activity index (CDAI) at 52 weeks. Associations between serum levels of ROM, C-reactive protein (CRP), and matrix metalloproteinase-3 (MMP-3) at 4 and 12 weeks and the remission by DAS28-ESR and CDAI at 52 weeks were investigated. Results There were no significant differences in CRP and MMP-3 between DAS- or CDAI-remission and non-remission groups at 12 weeks. However, ROM in DAS-remission group were significantly lower than those in the non-remission group. For ROM, the area under the curve of the receiver operating characteristic curve was 0.735 and the cut-off value that distinguished DAS-remission group from non-remission group was 305.5 U. Carr (sensitivity: 70.0%, specificity: 72.2%). A multivariate logistic regression analysis revealed that ROM at 12 weeks was associated with DAS-remission at 52 weeks (odds ratio: 6.067, 95% confidence interval: 1.305–28.203). Conclusion Serum levels of ROM at 12 weeks during TCZ therapy may be predictive of DAS-remission at 52 weeks in patients with RA.