It has been reported that various antioxidants decrease in rheumatoid arthritis (RA). Total antioxidant response (TAR), whose measurement method has been recently specified and developed, represents the total antioxidant properties of all antioxidants. This study aims to measure total antioxidant capacity in RA using TAR and evaluate its relations with oxidative stress.

The study included 47 active RA cases, and 23 age- and sex-matched healthy volunteers as the control group. TAR and total peroxide (TP) were studied using appropriate methods and oxidative stress (OSI) was calculated.

TAR level was 1,02±0,09 and 1,16±0,08 mmol Trolox eq./L in the patient group and the control group, respectively; TP level was 23,84±10,10 and 7,72±1,86 µmol H2O2/L in the patient group and the control group, respectively; and OSI value was 2,34±1,19 and 0,67±0,18 Arbitrary Units in the patient group and the control group, respectively. When compared with the control group, TAR level was significantly lower, and TP and OSI levels were significantly higher in the patient group (p<0.001 for each). TAR level was negatively correlated with TP and OSI levels both in the patient group (r=-0.534, p<0.01 and r=-0.552, p<0.01, respectively) and the control group (r=-0.469, p<0.05 and r=-0.382, p<0.05, respectively).

The results of our study indicate an increase in oxidative stress and lipid peroxidation products and a decrease in antioxidant capacity in RA cases.