The aim of this retrospective study was to examine the longitudinal association between disease activity and radiographic damage in a cohort of patients with early RA (symptom onset < 1 year) treated according to treat-to-target (T2T) therapy.
Baseline to 3-year follow-up data were used from patients included in the DREAM remission induction cohort. Patients received protocolized T2T treatment, aimed at 28-joint disease activity score-erythrocyte sedimentation rate (DAS28-ESR) remission. Disease activity (DAS28-ESR and C-reactive protein, CRP) were assessed at least every 3 months; X-rays of the hand and feet at inclusion, 6 months, and 1, 2, and 3 years were scored using modified Sharp/van der Heijde scoring (SHS). Between and within-person associations between time-integrated disease activity and radiographic progression over time were examined.
A subset of 229 out of 534 included patients were available for analysis. At the between-patient level, time-integrated DAS28-ESR scores were not significantly correlated with progression at the 6 month and 2-year follow-up and only weakly at the 1-year (Pearson's correlation coefficient r = 0.17, P < 0.05) and 3-year follow-up (r = 0.21, P < 0.05). Individual slopes of the relationship between DAS28-ESR and progression scores in each time interval were significantly correlated over time and the slope of the first 6 months was moderately associated with this slope at later time points (r between 0.39 and 0.59; P values < 0.001). Between 15.9 to 22.7% and 16.7 to 38.5% of patients with low and moderate time-integrated disease activity, respectively, experienced relevant (ΔSHS ≥ 3) radiographic progression at the different time intervals. Analyses using CRP showed similar results.
Netherlands Trial Register NTR578, 12 January 2006.
In early RA patients treated according to T2T, radiographic progression appears to be an individually determined disease process, driven by factors other than consistent high disease activity. For individual patients, the intra-patient relation between disease activity and cumulative radiographic damage during the first 6 months is a good indicator for this relation in later years.