One-year increase of Coll 2-1, a new marker of type II collagen degradation, in urine is highly predictive of radiological OA progression

Objective: To analyse the relationship between the levels of urinary biochemical markers of type 11 collagen degradation and the clinical and radiological severity and progression of knee osteoarthritis (OA). Method. Seventy-five patients with primary knee OA were included in this 3-year follow-up study. Mean joint space width (JSW) of the medial compartment of the femorotibial joint was measured with a computer assisted method on standardized radiographs taken at baseline and after a 3-year follow-up. Pain, stiffness, and physical function subscales of the Western Ontario and McMaster Universities (WOMAC) were assessed at the same time points. Type 11 collagen peptides Coll 2-1 and Coll 2-1 NO2, as well as pyridinoline (Pyr) and deoxypyridinoline (D-Pyr) were measured in urines at baseline, after 1 year and 3 years, with specific immunoassays. Results: At baseline, significant correlations were found between the urinary Coll 2-1 and Coll 2-1 NO2 levels and the global WOMAC score (Coll 2-1: r = 0.28, P = 0.01; Coll 2-1 NO2: r 0.27, P = 0.02) and its subscales for pain (Coll 2-1: r = 0.27, P = 0.01; Coll 2-1 NO2: r = 0.30, P = 0.01) and function (Coll 2-1: r = 0.29, P = 0.01; Coll 2-1 NO2: r = 0.27, P = 0.02). Pyr and D-Pyr levels were not significantly correlated with the WOMAC scores. One-year change in Coll 2-1 and Coll 2-1 NO2 urinary levels were negatively correlated with a 3-year change in JSW (Coll 2-1: r = -0.31, P = 0.03; Coll 2-1 NO2: r = -0.31, P = 0.03), indicating that an increase of Coll 2-1 or Coll 2-1 NO2 over 1 year is predictive of subsequent joint space narrowing. Neither Pyr nor D-Pyr was correlated with radiological CA progression. Conclusions: At baseline, Coll 2-1 and Coll 2-1 NO2 urinary levels were indicative of the clinical activity of knee CA and the increase of these peptides over 1 year was predictive of the radiological progression of knee OA. (c) 2005 OsteoArthritis Research Society International. Published by Elsevier Ltd. All rights reserved.