To assess whether serum C-terminal cross-linking telopeptide of type I collagen (ICTP), a marker of type I collagen degradation, has any additional value in the assessment of treatment effect in patients with early rheumatoid arthritis (RA).
A total of 182 patients were randomized to treatment either with three disease-modifying anti-rheumatic drugs (DMARDs) and low-dose prednisolone (COMBI) or with a single DMARD with or without low-dose prednisolone (SINGLE). We investigated the prognostic value of serum ICTP level for the progression of joint destruction in X-rays (Larsen's score) from baseline to 2 years.
There was a statistically significant decrease in serum ICTP levels from baseline to 1 year. At 6 months, the serum ICTP level was lower in the COMBI patients compared to that of the SINGLE cases (p = 0.008, after adjustment for baseline ICTP). When grouping the patients according to serum ICTP tertiles at 6 months, there was a statistically significant trend for increasing median change in Larsen score from baseline to 2 years from lowest to highest ICTP tertile in the SINGLE patients [p = 0.008, after adjustment for 28-joint Disease Activity Score (DAS28) score and RF status at baseline], while in the COMBI, the change remained low in all ICTP tertiles.
The COMBI strategy for recent-onset RA results in early suppression of type I collagen degradation, which is reflected in radiological joint damage at 2 years. Serum ICTP at 6 months may be useful for identifying those RA patients whose treatment should be intensified to prevent further joint damage.