Evaluation of the relationship between uric acid levels and disease activity in patients with rheumatoid arthritis

Introduction and Aim: The aim of this study was to retrospectively investigate the relationship between serum uric acid levels and disease activity, serological status, organ involvement, and the use of antirheumatic drugs in patients with Rheumatoid Arthritis (RA). Materials and Methods: A total of 252 individuals were included in the study, comprising 84 seropositive RA, 84 seronegative RA, and 84 osteoarthritis (OA) patients as the control group. Demographic data, DAS28 scores, laboratory parameters (uric acid, CRP, ESR, SII, etc.), and treatments were analyzed from patient records. Results: The main finding of the study is that uric acid levels were statistically significantly lower in the RA patient group, particularly in seropositive RA patients (4.3±1.2 mg/dL), compared to the OA control group (5.2±1.2 mg/dL). No significant correlation was found between uric acid levels and disease activity scores (DAS28) or CRP. When treatments were examined, uric acid levels were significantly lower in patients using leflunomide (p=0.000) , whereas, contrary to the literature, they were found to be higher in those using methotrexate (p=0.035). Even when patients not using leflunomide were analyzed separately, the trend of low uric acid in the seropositive group persisted, suggesting that this condition may not only be due to the drug's effect but also related to seropositivity itself. The frequency of lung involvement (14.3%) and pulmonary nodules (35.7%) was higher in seropositive RA patients compared to seronegative patients. Conclusion: In this study, uric acid was not found to be a reliable indicator of RA disease activity. The low uric acid levels observed in seropositive RA are partly associated with leflunomide treatment but also point towards the potential role of other underlying biological mechanisms. Keywords: Rheumatoid Arthritis, Uric Acid, Disease Activity, DAS28, Leflunomide, Seropositive