Background The commonly used remission criteria DAS-ESR and DAS-CRP rather define minimal disease activity than remission. ACR/EULAR recently developed new definitions of remission1 (A/E criteria) that reflect more accurately a patient population in clinical remission. ACR/EULAR also endorses the definition of remission according to the SDAI (SDAI≤3.3). The purpose of this analysis is to compare the performance of the different remission criteria in a real-world Canadian patient population treated with infliximab (IFX).
Methods BioTRAC is an ongoing, non-interventional study of patients (pts) starting IFX as first biologic or after having been treated with a biologic for less than six months. Pts with rheumatoid arthritis (RA) who have been enrolled for at least 6 months (mo) ago are included in this analysis. Remission rates at 6 mo are based on a modified ITT analysis, including all pts with sufficient information reported.
Results A total of 775 established RA patients were included in this analysis. At 6 mo 33%, 28%, 17% and 8% of the pts achieved remission as defined by DAS28-CRP (≤2.6), DAS28-ESR (≤2.6), SDAI (≤3.3) or the A/E criteria, respectively.
In general, mean clinical parameters at 6 mo were higher in pts in DAS-CRP and in DAS-ESR remission compared to pts in SDAI or in A/E remission. The only exceptions were CRP, which was lowest in pts in DAS-CRP remission, and ESR, which was lowest in pts in DAS-ESR remission, reflecting the high weighing of the acute phase reactants in the DAS criteria. When comparing clinical characteristics at 6 mo between pts in SDAI and pts in A/E remission, mean CRP, ESR, Phys. Global Assess., DAS28-ESR, DAS28-CRP and SDAI score were comparable, while morning stiffness, HAQ, TJC, SJC, Pat Global Assess. were lower in pts in A/E remission. Pts in A/E remission at 6 mos consistently had the lowest HAQ over a 4 year period (as observed analysis), with mean HAQ<0.5, suggesting that pts achieving stringent remission criteria regain normal function and maintain it over 4 years.
Multivariate regression analysis showed that baseline characteristics predicting remission according to the different criteria at 6 mo did not differ greatly. Male gender and HAQ were the major prediction factors for remission.
Conclusions The results of this real-world study show that pts in DAS remission have higher disease activity than pts in SDAI or A/E remission. Although ACR/EULAR endorses both the SDAI as well as the A/E criteria, disease activity in pts in SDAI versus A/E remission was different in this real world pt population, with pts in A/E remission having lower disease activity. Stringent remission 6 mo after IFX initiation was associated with a normal functional outcome (mean HAQ<0.5) over 4 years.
Felson et al. Arthritis Rheum. 2011. 63(3): 573
Disclosure of Interest None Declared