To compare type II collagen degradation using a new urinary specific marker in patients with rapidly destructive and those with slowly progressive hip OA.
Twelve patients with rapidly destructive and 28 patients with slowly progressive hip OA were included in a prospective, cross sectional case-control study. Urinary levels of C-terminal crosslinking telopeptide of collagen type II (CTX-II) as a marker of cartilage degradation were measured by an ELISA, and urinary free deoxypyridinoline (free DPD), a marker of bone resorption, was measured by high performance liquid chromatography. One x ray evaluation of the hips and urine samples was made in all patients when the diagnosis of OA was established.
Patients with hip OA had higher mean (SD) urinary CTX-II levels than 65 healthy age matched controls (492 (232) v 342 (141), p<0.001), but no significant difference was seen for urinary free DPD (p=0.30). Increased urinary CTX-II, but not urinary free DPD, correlated significantly with decreased minimum joint space width assessed by radiograph of the hip. Mean urinary CTX-II levels were significantly higher in patients with rapidly progressive OA than in the slowly progressive group (612 (218) v 441 (221), p=0.015), whereas no significant difference of urinary free DPD was seen between the two groups (p=0.55).
Patients with hip OA have increased CTX-II degradation as assessed by a new urinary marker. Increased urinary CTX-II levels are associated with rapidly destructive disease, suggesting that this marker might be useful in identifying patients with hip OA at high risk for rapid progression of joint damage.