Background The aim of the present study was to evaluate the efficacy of anti-TNF treatment on urinary type-II collagen C-telopeptyde (CTX-II) levels which is a cartilage destruction marker in patients with rheumatoid arthritis (RA).

Objectives 39 patients with RA and 36 healthy controls who were compatible in terms of age and sex were included. Urine CTX-II values of the patients were measured by CartiLaps ELISA test at baseline and after 3 months. The cut-off for CTX-II was 479ng/mmol.

Methods Disease activity was measured by the disease activity score (DAS28), swollen and tender joints count, patient’s and physician’s global assessments, C-reactive protein (CRP). Disease status was measured using The Disease Activity Score (DAS28) C reactive protein criteria. Health Assessment Questionnaire (HAQ) was filled by patients for functional disability.

Results Patients with RA had significantly higher levels of CTX-II at baseline compared to healthy controls (447.8±359.3 and 233.8±122.4; p=0.005). After the adjustment for disease duration, urinary CTX-II levels were positively correlated with mTSS, erosion and joint space narrowing scores (p=0.002; p=0.009; p=0.001 respectively). There was a significant correlation between urinary CTX-II values and DAS28 (r=+0.609, p < 0.001).

After 3 months, a significant improvement was observed in all parameters. Decrease in urinary CTX-II values was statistically significant in early RA patients compared to baseline values(p=0.016). However, a statistically significant difference was not observed in established RA.

At the 3^rd month, a greater decrease proportion in urinary CTX-II values was observed in early RA patients who had higher urinary CTX-II levels at baseline. A decrease of 64% at urine CTX-II level was observed in 11 patients with early RA.

Conclusions CTX-II is a biochemical marker that shows good correlation with radiologic and clinical parameters in patients with RA. The significant decrease of CTX-II levels at the 3^rd month in early RA patients supports the benefits of early administration of anti-TNF treatment on cartilage destruction. Baseline high urinary CTX levels may be a good predictor of response to anti TNF therapy.

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Disclosure of Interest None Declared