Serum cartilage oligomeric matrix protein as a biomarker for predicting development and progression of knee osteoarthritis.

PURPOSE

Current modes of diagnosing and monitoring knee osteoarthritis (OA) are based on weight bearing radiographs usually made by the time joint destruction is already established. Cartilage oligomeric matrix protein (COMP) is a breakdown product of cartilage and its serum levels may be a potential indicator of early destruction in OA. This study aimed to ascertain the usefulness of serum COMP (sCOMP) in diagnosis and monitoring of knee joint OA within the study environment.

METHODS

Ninety consenting adults were recruited. In the control group, 45 subjects having a diagnosis of knee OA had clinical and radiological grading done and blood samples taken for assay of sCOMP using the sandwich ELISA method. Forty-five volunteers with no features of osteoarthritis also had serum collected for sCOMP assay. Values obtained were then cross referenced with demographic indices, clinical and radiological severity grade to assess for relationships.

RESULTS

Serum COMP was found to be significantly elevated (p = 0.0001) in the study group. The mean values and standard deviation of sCOMP were 3400 ± 1042.9 ng/ml and 2222 ± 605.6 ng/ml for the study and control groups, respectively. Higher values of sCOMP were found to be associated with higher clinical and radiological grades of OA.

CONCLUSION

The study demonstrates that sCOMP is significantly higher in patients with knee OA than in those without the disease. Values of sCOMP were also found to increase with severity of knee OA, indicating the possibility of its use as a marker of diagnosis and severity.