High level of serum cartilage oligomeric matrix protein and plasma interleukin-6 increase the risk of ultrasound-detected synovial inflammation in knee osteoarthritis

ABSTRACT Background: Inflammation of the synovial membrane involved in knee osteoarthritis (OA) pathomechanism. Cartilage oligomeric matrix protein (COMP) is a cartilage degradation product that has been considered as a biomarker of OA. Interleukin-6 (IL-6) is an inflammatory mediator involved in the pathogenesis of synovial inflammation in knee OA. This study was conducted to proof whether high level of serum COMP and plasma IL-6 increase the risk of synovial inflammation in knee OA. Methods: This was a case control study to proof about the risk of synovial inflammation in primary knee OA patients who were exposed by high level of circulating serum COMP and plasma IL-6. Every case was matched with his/ her control using pair by pair method (pair-matched). Research data was analyzed using statistic computer software program. Results: There were 56 subjects in case group and 56 subjects in control group. Bivariate analysis found that serum level of COMP gave risk for having synovial inflammation 5.5 times higher than control group (p< 0.001). High level of plasma IL-6 gave risk of synovial inflammation 2.88 times higher than control group (p < 0.05). Multivariate analysis found that high level of serum COMP and plasma IL-6 were still significantly increased the risk factors for the development of synovial inflammation in knee OA (adjusted-OR= 3, p < 0.05 for high level of serum COMP; and adjusted-OR=2.7, p < 0.05 for high level of plasma IL-6). Conclusions: High level of serum COMP and also high level of plasma IL-6 is proven increasing the risk of synovial inflammation in knee OA.