Response to 'Pain persists in DAS28 rheumatoid arthritis remission but not in ACR/EULAR remission: a longitudinal observational study'

the June issue of Arthritis Research & Th erapy [1]. Th e study compared the Disease Activity Score in 28 joints calculated by using C-reactive protein (DAS28-CRP) versus American College of Rheumatology/European League Against Rheumatism (ACR/EULAR) remission in terms of residual pain. Th e authors stated that DAS28CRP remission criteria allowed for persistence of pain in more than 10% of patients, whereas there were very few com plaints of pain among patients in ACR/EULAR remission. Th is is a very important fi nding as it clearly demon strated incompetence of the DAS28-CRP remission criteria in defi ning remission that is meaningful for patients, thus encouraging transition to new ACR/ EULAR remission criteria. One factor, however, that was not mentioned in the article and which may be of interest is the Disease Activity Score in 28 joints calculated by using erythrocyte sedimentation rate (DAS28-ESR). Although the DAS28CRP is a validated score demon strating good correlation with the DAS28-ESR [2], the DAS28-CRP frequently results in lower scores than its erythrocyte sedimentation rate counterpart [2,3]. Inoue and colleagues thus suggested a diff erent cut-off point of 2.3 for the DAS28-CRP [3]. Th is tendency was also demonstrated in our cohort of 265 rheumatoid arthritis patients taking biologics (Figure 1). When plotted against the DAS28-ESR, the DAS28-CRP resulted in lower values (below the diagonal line, indicating complete agreement) more often than not. Also noteworthy is that the DAS28-CRP is never lower than 0.96, which is the constant term in the following equation [4]: DAS28-CRP = 0.56 × √TJC28 + 0.28 × √SJC28 + 0.36 × ln(CRP + 1) + 0.014 × GH + 0.96