To select sub-clinical patients with symptoms of knee osteoarthritis (KOA) without X-ray changes by measuring the serum level of cartilage oligomeric matrix protein (COMP) with ELISA, so as to diagnose and treat patients with knee osteoarthritis at early stage.
The 115 patients with KOA or with symptomatic primary KOA were enrolled from August 2007 to September 2009, which was OA group; and 35 healthy people in the control group. In OA group, there were 55 males and 60 females,ranging in age from 39 to 76 years, with an average of (55 +/- 13.32) years; the body mass index (BMI) ranged from 15.1 to 29.8; the disease course ranged from 6 to 60 months. In the control group, there were 16 males and 19 females, ranging in age from 36 to 77 years, with an average of (53 +/- 12.53) years; the BMI ranged from 14.8 to 29.2. Patients with symptomatic primary knee OA of Kellgren-Lawrence (K-L) grade I-IV were evaluated. Serum level of COMP and its correlation with OA grade were analyzed by ELISA method. The patients were treated with Celecoxib capsules. The patients in OA group were followed up, and the duration ranged from 24 to 38 months (averaged, 33.4 months), and the serum level of COMP were analyzed before and after treatment.
The serum level of COMP in the control group varied with age (t= 2.50, P=0.02). The serum level of COMP did not correlate with gender (control group: t=0.98, P=0.34; OA group: t=0.18, P= 0.86), BMI (control group: t=0.56, P=0.92; OA group: t=0.17, P=0.85) and smoking (control group: t=1.89, P=0.08; OA group: t=0.70, P=0.49). The serum level of COMP was higher in the patients with higher K-L grades than in the patients with lower K-L grades (F=15.56, P=0.001) . The sub-clinical KOA patients without X-ray changes can be detected significant higher COMP levels than sub-clinical patients with other diseases (t=2.55, P=0.03). Therefore, according to this method, subclinical OA patients can be detected from people with other sub-clinical diseases successfully.
The serum level of COMP can be used as a potential prognostic marker to diagnose KOA.