Comparison between ESR and C-Reactive Protein(CRP) as a Marker of Disease activity in Patients with Rheumatoid Arthritis

Abstract

Background: Laboratory tests such as the erythrocyte sedimentation rate(ESR) and C-reactive protein (CRP) have been used as markers of inflammation and disease activity in rheumatoid arthritis (RA), although there is still no clear consensus on when to use one, the other, or both. Objective: To determine ESR and CRP values in active RA patients and their correlation with different parameters of disease activity. Patients and Methods: Eighty patients with active RA, attending rheumatology department at Benha Teaching Hospital, diagnosed according American College of Rheumatology (ACR) and European League Against Rheumatism (EULAR) revised criteria were included. The patients' tender and swollen joint counts were calculated. Laboratory investigations were done including ESR by Westergren method and CRP by ELISA method, assessment of disease activity using DAS28 score. Results: All patients showed disease activity at time of the study, their DAS28 score was ranged from 2.9 to 7.5 (Mean±SD 5.42±1.1). The values of ESR was ranged from 10 to 150 mm/h in first hour (Mean ±SD 52.9±33.9). CRP was positive in 54 patients but negative in 26 (67.5% versus 32.5%), the CRP values was ranged from 0.6 to 65 mg/dl (Mean±SD 18.1±15.8). There were statistically significant correlation between DAS28 values and number of tender & swollen joints and ESR values (P-value was <0.001, <0.001, 0.004 respectively), on the other hand there was no significant correlation between DAS28 patients age and CRP values (P value was 0.60, 0.18 respectively). Conclusion: our study suggests that CRP is not a viable marker in the clinical setting to monitor inflammatory activity in the RA patient, and that the role of and dependence on CRP as a marker of inflammation in RA patients in everyday practice should be re-evaluated.