Comparison of disease activity by disease activity score-28 C-reactive protein and disease activity score-28 erythrocyte sedimentation rate in established rheumatoid arthritis patients – A comparative study

Objective. To compare disease activity in patients of established Rheumatoid Arthritis estimated by Disease Activity Score-28 (DAS-28) C-reactive protein (CRP) and Disease Activity Score-28 Erythrocyte Sedimentation Rate (ESR). Material and Methods: This cross-sectional comparative study was conducted at Department of Rheumatology, Pak Emirates Military Hospital Rawalpindi, May 2022 to Oct 2022. Using consecutive non probability sampling, patients of Rheumatoid Arthritis (RA) of 30 to 65 years age of either gender were selected who had the disease for at least 1 year, never received biologics Disease modifying anti-rheumatic drugs (DMARDs) or immunosuppressive therapy and no signs of active infective etiology. DAS28 score was calculated using ESR and CRP to assess disease severity. Sensitivity, specificity, and agreement comparison was done between DAS28-ESR and DAS28-CRP and κ -coefficient was calculated with discordance proportion. Results. Out of 70 patients, 50 (70%) were female and 20 (28%) were male with mean age of included patients 49.9 ± 7.5 years. Mean disease activity score, calculated using ESR was 4.1 ± 1.25 SD was higher than mean DAS28 score of 3.5 ± 1.12 SD with CRP. Twenty (28.6%) patients had High Disease Activity (HDA) (DAS28 > 5.1) when assessed by DAS28-ESR score as compared to 8 (11.4%) patients by DAS28-CRP score with 17.1% discordance and κ Coefficient of 0.402 corresponding to minimal agreement amid DAS28-ESR and DAS28-CRP for HDA (p < 0.005). DAS28 score using ESR as evaluating tool had 35% sensitivity and 98% specificity of detecting RA patients with High Disease Activity. Conclusion. DAS28-ESR was preferable as compared to DAS28-CRP for monitoring disease activity and treatment decision. Keywords. C-reactive protein (CRP), Disease activity score (DAS), Erythrocyte sedimentation rate (ESR), Joint pain, Rheumatoid arthritis, Visual analogue scale (VAS)