To investigate if a glucocorticoid (GC) response at 2 weeks, defined by EULAR response criteria, can predict active disease (Disease Activity Score (DAS)>2.4) at 3 months.
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 2 weeks after randomisation, were included (n=120). Besides GC response at 2 weeks, we investigated which other factors were associated with active disease (DAS>2.4) after 3 months of disease-modifying antirheumatic drug (DMARD) treatment. All variables with a p≤0.25 were assessed in our logistic regression model with backward selection. Variables were eliminated until all remaining variables had a significant association (p<0.05).
Patients who did not respond to GC bridging therapy at 2 weeks had an overall OR of having active disease at 3 months 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 3 months included the following variables: gender, GC response, induction therapy arms and baseline DAS, which had an explained variance of 39%.
GC response at 2 weeks is a useful tool for recognising those patients who will probably have active disease (DAS>2.4) after 3 months of DMARD treatment.