The plasma levels of circ_0005008 and circ_0005198 in new-onset patients with RA both showed positive correlations with the disease activity score in 28 joints (DAS28) (r = 0.699, p < 0.001; r = 0.512, p = 0.001), the erythrocyte sedimentation rate (ESR) (r = 0.595, p < 0.001; r = 0.519, p = 0.001), C-reactive protein (CRP) (r = 0.473, p = 0.002; r = 0.434, p = 0.005), and rheumatoid factor (RF) (r = 0.397, p = 0.011; r = 0.469, p = 0.002), respectively, all of which are indicators of disease severity. Here, CRP is linked to rheumatoid arthritis.