Evaluation of serum calprotectin level as a biomarker of disease activity in rheumatoid arthritis and osteoarthritis patients

Aim of the work: To measure the levels of serum calprotectin (CLP) in rheumatoid arthritis (RA) and osteoarthritis (OA) patients and to assess its association with disease activity, severity and functional status. Patients and methods: A total of 30 RA and30 OA patients and 30 controlswere included. Rheumatoid factor (RF), anti-cyclic citrullinated peptide (anti-CCP), Disease activity score (DAS28), health assessment questionnaire (HAQ) and RA medical records-based index of severity (RARBIS) were assessed in RA patients. Western Ontario and McMaster Osteoarthritis index (WOMAC) and Kellgren-Lawrence (KL) grading scale were assessed in OA patients and serum CLP levels were measured. Results: The mean age of RA and OA patients was 48.6 +/- 8.6 and 50.8 +/- 9.3 years respectively andthe majority of studied groups were females. CLP was significantly higher in RA patients in comparison to OA patients and healthy control (2.70 +/- 2.08 vs. 1.18 +/- 0.35 vs 1.11 +/- 0.24 lg/ml); p < 0.0001). Serum CLP correlated with swollen joint count (SJC) (r = 0.7, p < 0.0001), tender joint count (TJC) (r = 0.73, p < 0.0001), patient global assessment (PGA) (r = 0.51, p = 0.004), Physician global assessment (PhGA) (r = 0.58, p = 0.001), HAQ (r = 0.6,p < 0.0001), erythrocyte sedimentation rate (ESR) (r = 0.5, p = 0.005), DAS28 (r = 0.69, p < 0.0001), RARBIS (r = 0.66, p < 0.0001). At a cut-off value of 2.5 mg/ml CLP can significantly differentiate active RA patients from those in remission (AUC 0.896; p < 0.0001) at a sensitivity of 83.3%, specificity of 88.9%, and accuracy of 86.7%.CLP was significant predictor for RA activity. Conclusion: The serum CLP levels were significantly high in RA patients compared to OA patients and controls and these high levels were associated with disease activity, severity, and functional status. (c) 2021 THE AUTHORS. Publishing services by ELSEVIER B.V. on behalf of The Egyptian Society of Rheumatic Diseases This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/).