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Increased serum concentrations of Nɛ-carboxymethyllysine are related to the presence and the severity of rheumatoid arthritis

Background There are limited data regarding the contribution of advanced glycation end products in the presence of rheumatoid arthritis. We investigated whether serum Nɛ-carboxymethyllysine and pentosidine were related to the presence and the severity of rheumatoid arthritis. Methods Eighty patients with rheumatoid arthritis and 30 control subjects were included in a cross-sectional study. The severity of rheumatoid arthritis was assessed using the disease activity score for 28 joints. Serum Nɛ-carboxymethyllysine and pentosidine were measured by enzyme-linked immunosorbent assay. Results Serum Nɛ-carboxymethyllysine and pentosidine concentrations were significantly higher in patients with rheumatoid arthritis vs. control subjects (P < 0.001). Serum Nɛ-carboxymethyllysine and pentosidine concentrations were significantly higher in rheumatoid arthritis patients with high disease activity vs. rheumatoid arthritis patients with moderate disease activity (P < 0.001, P = 0.019, respectively). A multiple logistic regression analysis demonstrated that Nɛ-carboxymethyllysine was independently associated with the presence of rheumatoid arthritis (OR = 1.21, 95% CI: 1.05–1.39, P = 0.006). Furthermore, in a multivariate stepwise regression analysis, Nɛ-carboxymethyllysine was independently correlated with disease activity score for 28 joints (standardized β = 0.43, P = 0.001). Conclusion Serum Nɛ-carboxymethyllysine and pentosidine were increased during rheumatoid arthritis, and Nɛ-carboxymethyllysine was independently associated with the presence and the severity of rheumatoid arthritis.