Increased serum concentrations of N-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 N-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 N-carboxymethyllysine and pentosidine were measured by enzyme-linked immunosorbent assay. Results Serum N-carboxymethyllysine and pentosidine concentrations were significantly higher in patients with rheumatoid arthritis vs. control subjects ( P < 0.001). Serum N-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 N-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, N-carboxymethyllysine was independently correlated with disease activity score for 28 joints (standardized β = 0.43, P = 0.001). Conclusion Serum N-carboxymethyllysine and pentosidine were increased during rheumatoid arthritis, and N-carboxymethyllysine was independently associated with the presence and the severity of rheumatoid arthritis.