Urine levels of type 1 collagen cross-linked N-telopeptides and deoxypyridinoline correlate with disease activity in rheumatoid arthritis

Objectives The aim of this study was to find out whether spot urinary concentrations of type I collagen cross-linked N-telopeptides (NTx) and deoxypyridinoline (Pyrilinks-D) can differentiate between active and inactive disease in rheumatoid arthritis (RA) and to investigate the extent to which they correlate with indices of disease activity. Methods Using enzyme-linked immunosorbent assays, the concentrations of NTx and Pyrilinks-D were estimated in spot urine samples fi om 25 females with active disease, 25 females with inactive disease, and in 25 controls. Results In patients with active disease, urinary concentrations of NTx and Pyrilinks-D were significantly higher (p < 0.01) than in those with inactive disease or in healthy controls. In active disease there were significant positive correlations between urinary NTx and ESR, the swollen joint count, the tender joint count, and the patient's global assessment. Conclusion The NTx concentration in spot urine correlates with disease activity in patients with RA.