In RA patients, HA concentration positively correlated with ESR (r = 0.26, P = 0.028) and with CRP value (r = 0.54, P = 0.009) but did not correlate with DAS28 (r = 0.13, P = 0.300), visual analog scale (VAS) (r = 0.22, P = 0.282), health assessment questionnaire (HAQ) (r = 0.02, P = 0.934) and the number of swollen (r = - 0.01, P = 0.966) and tender (r = - 0.09, P = 0.657) joints (Table 3, Table 4). Here, CRP is linked to rheumatoid arthritis.