The association of treatment response and joint damage with ACPA-status in recent-onset RA: a subanalysis of the 8-year follow-up of the BeSt study

Objective Anticitrullinated protein antibodies (ACPAs) are suggested to identify different subsets of patients with rheumatoid arthritis (RA). The authors compared the clinical and radiological responses to Disease Activity Score (DAS)-steered treatment in patients with RA positive or RA negative for ACPA. Methods In the BehandelStrategieen (BeSt) study, 508 patients with recent-onset RA were randomised to four treatment strategies aimed at a DAS ≤2.4. Risks of damage progression and (drug-free) remission in 8 years were compared for ACPA-positive and ACPA-negative patients using logistic regression analysis. Functional ability and DAS components over time were compared using linear mixed models. Results DAS reduction was achieved similarly in ACPA-positive and ACPA-negative patients in all treatment strategy groups, with a similar need to adjust treatment because of inadequate response. Functional ability and remission rates were not different for ACPA-positive and ACPA-negative patients. ACPA-positive patients had more radiological damage progression, especially after initial monotherapy. They had a lower chance of achieving (persistent) drug-free remission. Conclusion Clinical response to treatment was similar in ACPA-positive and ACPA-negative patients. However, more ACPA-positive patients, especially those treated with initial monotherapy, had significant radiological damage progression, indicating that methotrexate monotherapy and DAS- (≤2.4) steered treatment might be insufficient to adequately suppress joint damage progression in these patients.