Performance of serum adenosine deaminase in measuring disease activity in rheumatoid arthritis patients

Background: Numerous tools to assess activity of rheumatoid arthritis (RA) are available to use. For any marker to be a more appropriate indicator of disease activity, it should be more authentic to the pathophysiologic basis of the disease. Aim of the work: To determine the performance of serum adenosine deaminase (sADA) in measuring disease activity in RA. Patients and Methods: 100 RA patients and 100 matched controls were included in the study. The disease activity score (DAS28) with erythrocyte sedimentation rate (ESR) and C-reactive protein (CRP) were assessed. sADA level was determined by spectrophotometry. The sADA level was integrated in the DAS28 formulae and the corresponding values were determined. Results: The mean age of the RA patients was 61.8 +/- 9.7 years, 68% were females and they had a disease duration of 12.5 +/- 3.7 years. The mean DAS28-ESR was 4.2 +/- 1.3 and DAS28-CRP 3.5 +/- 1.1. The mean sADA was significantly higher in the patients (33.6 +/- 11.6 U/L) compared to the control (25.1 +/- 9.9 U/L) (p < 0.001). The sADA level and DAS28-sADA did not differ according to the gender, methotrexate use, rheumatoid factor or anti-citrullinated protein autoantibodies positivity. The mean DAS28-sADA significantly increased in higher activity categories (p < 0.001). sADA significantly correlated with the disease activity parameters. DAS28-sADA significantly correlated with DAS28-ESR (r = 0.57, p < 0.001) and DAS28-CRP (r = 0.604, p < 0.001). DAS28-sADA showed a sensitivity of 0.9 and specificity 0.69 for detection of disease activity measured with DAS28-ESR and was 0.88 and 0.65 when measured with DAS28-CRP. Conclusion: Integration of sADA in the DAS28 index can be a useful marker that reflects RA activity. (C) 2018 Publishing services provided by Elsevier B.V. on behalf of Egyptian Society of Rheumatic Diseases.