The value of serum total oxidant to the antioxidant ratio as a biomarker of knee osteoarthritis.

Background & Aims: The balance between oxidants and antioxidants is known as oxidative balance, which is impaired in many disease conditions such as osteoarthritis (OA). In this study, we aimed to evaluate this balance in OA patients through the evaluation of the oxidant to the antioxidant ratio.

Materials And Methods: A total of 62 knee OA patients and 20 age, sex, and BMI-matched healthy controls were included in this cross-sectional study. Serum total oxidant status (TOS) and total antioxidant capacity (TAC) were evaluated using the oxidation-reduction colorimetric assay. The TOS to TAC ratio (TOS/TAC) was evaluated as an estimate of the oxidant to antioxidant balance.

Results: The mean TOS was 14.2 ± 2 μM in the healthy controls and 23.3 ± 7 μM in the OA patients (p < 0.001). The mean TAC was 38.8 ± 6.6 μM in the healthy subjects and 35.8 ± 12 μM in the OA patients (p = 0.33). The mean TOS/TAC was 0.38 ± 0.09 in the healthy subjects and 0.72 ± 0.3 in the OA patients (p < 0.0001). TOS/TAC value was capable of distinguishing OA patients from healthy controls with the sensitivity and specificity of 87.1% and 80%, respectively (p < 0.001). At the cutoff value of 0.46, positive TOS/TAC (>0.46) was identified in 100% of grade I patients, whereas it was negative in 27.3%, 16.7%, and 16.7% of grades II, III, and IV, respectively (p = 0.039).

Conclusion: In the knee OA, an equation of the serum TOS to TAC could be a good representative of oxidative balance than each component individually.