Among patients with newly diagnosed rheumatoid arthritis (RA), Disease Activity Score 28-joint count (DAS28) characterized using C-reactive protein (CRP) values are lower than the corresponding score using erythrocyte sedimentation rate (ESR) values, both at baseline high disease activity and post-treatment, according to study results published in ACR Open Rheumatology.
Disease activity scores are used to guide treatment and determine the efficacy of therapeutic strategies. Previous studies have shown that DAS28-CRP values are lower than DAS28-CRP values, but current guidelines do not provide specific cutoffs for high disease activity for each of the scores.
Existing studies that compared DAS28-CRP and DAS28-ESR used data from patients who received immunosuppressive therapy. The objective of the current study was to compare the scores from immunosuppressive treatment-naïve patients.
The retrospective electronic chart review included 171 immunosuppressive treatment-naïve patients with newly diagnosed RA. DAS28-CRP and DAS28-ESR were compared according to the cutoff value for baseline high disease activity (>5.1). A receiver operator characteristic curve (ROC) and Youden index were used to calculate the DAS28-CRP high disease activity optimal cut-point value corresponding to DAS28-ESR >5.1.
At baseline, the mean DAS28-ESR was higher than the mean DAS-28 CRP (5.1 ± 1.2 vs. 4.1 ± 1.0; P <.001) and more patients met high disease activity criteria for DAS28-ESR than for DAS28-CRP (48.5% vs. 14.6%, respectively). ROC curve and Youden index analysis showed that the cutoff point estimation of high disease activity using DAS28-ESR >5.1 corresponded to a DAS28-CRP score <4.06 (area under the ROC curve = 0.93, P =.000).
Data on both DAS28-ESR and DAS28-CRP score following treatment were available for 151 patients. On average, DAS28-CRP values were 0.66 points higher than the corresponding DAS28-ESR. DAS28-CRP values were significantly lower compared with DAS28-ESR in all subgroups classified by gender, age, and disease severity.
In patients in remission (values <2.6), mean DAS28-CRP values were 0.36 points lower than the corresponding DAS28-ESR value (1.45 vs. 1.81, respectively).
The study had several limitations, including the racially homogeneous cohort (91.8% white), single center study, as well as lack of data on body mass index or comorbidities which may have a significant impact on the difference between DAS28-ESR and DAS28-CRP.
“There is a difference between DAS28-ESR and DAS28-CRP, even when calculated for immunosuppressive treatment–naïve patients. DAS28-CRP is significantly lower than DAS28-ESR,” wrote the researchers.
Greenmyer JR, Stacy JM, Sahmoun AE, Beal JR, Diri E. DAS28-CRP cutoffs for high disease activity and remission are lower than DAS28-ESR in rheumatoid arthritis. ACR Open Rheumatol. 2020;2(9):507-511. doi:10.1002/acr2.11171