Correlation between Serum Levels of Calprotectin with Disease Activity in Rheumatoid Arthritis Patients

Background and Objective: Rheumatoid arthritis (RA) is an autoimmune disease defined by chronic synovitis and progressive joint destruction. This study investigated calprotectin as a serological marker in the hope of establishing an adequate means of diagnosing RA and following up on patients. Materials and Methods: This cross-sectional study included 32 RA patients who were referred to the rheumatology clinic of Baqiyatallah Hospital (Tehran, Iran) from 2019 to 2020. clinical examinations and requested laboratory tests was performed. The final visit was placed after a year with the same method as the initial visit. Disease activity was assessed by Disease Activity Score 28 (DAS-28) for 28 joints which is assessable by ESR or CRP and data were analyzed by SPSS 20 version. Results: Changes over time were significant in both (P=0.00 and P=0.00), and a significant relationship was found between the quantitative scores of the two forms of DAS-28 (P<0.000). Calprotectin did not show any significant correlation with either form of the DAS-28 quantitatively. Ahead of logistic regression analysis on the after one-year C-reactive protein based DAS-28 data, patients with cured disease or low disease activity were combined into one group. Accordingly, calprotectin was able to predict RA activity level to some extent (P=0.06), though a more efficient prediction was achieved when erythrocyte sedimentation rate and calprotectin were applied together (P=0.03). Conclusion: ESR and calprotectin did not show good power in predicting disease activity individually but they could have significantly high prediction potency combined.