Response to glucocorticoids at 2 weeks predicts the effectiveness of DMARD induction therapy at 3months: post hoc analyses from the tREACH study

Objective To investigate if a glucocorticoid (GC) response at 2weeks, defined by EULAR response criteria, can predict active disease (Disease Activity Score (DAS)>2.4) at 3months. Methods For this study, data of the Treatment in the Rotterdam Early Arthritis Cohort study (tREACH), an ongoing clinical trial that evaluates different induction therapies in early rheumatoid arthritis, were used. We selected patients who had a high probability of progressing to persistent arthritis (>70% based on the prediction model of Visser). All patients within the high-probability stratum, who had a baseline DAS>2.2 and a DAS assessment at 2weeks after randomisation, were included (n=120). Besides GC response at 2weeks, we investigated which other factors were associated with active disease (DAS>2.4) after 3months of disease-modifying antirheumatic drug (DMARD) treatment. All variables with a p0.25 were assessed in our logistic regression model with backward selection. Variables were eliminated until all remaining variables had a significant association (p<0.05). Results Patients who did not respond to GC bridging therapy at 2weeks had an overall OR of having active disease at 3months of 10.29 (95% CI 3.34 to 31.64; p<0.001) in comparison with responders. The corrected OR was 14.00 (95% CI 3.31 to 59.21; p<0.001). Our final model predicting response at 3months included the following variables: gender, GC response, induction therapy arms and baseline DAS, which had an explained variance of 39%. Conclusions GC response at 2weeks is a useful tool for recognising those patients who will probably have active disease (DAS>2.4) after 3months of DMARD treatment.