THU0151 COMPARISON BETWEEN THREE PROPOSED DEFINTIONS OF DIFFICULT-TO-TREAT/REFRACTORY RHEUMATOID ARTHRITIS IN A COHORT OF BDMARD-TREATED PATIENTS

Background A definition of difficult-to-treat/refractory rheumatoid arthritis (RA) (RRA) has not been established yet, nevertheless, RRA is commonly associated with the resistance to multiple bDMARDs [1,2,3]. Objectives The objective was to evaluate the rate of RRA according to three definitions, the agreement between the definitions and major determinants of such definitions in a large monocentric cohort of RA patients. Methods We included RA patients treated with any bDMARD (>=1 year), who started bDMARDs after 2001. Considered definitions of RRA were: B-RAA, according to Buch [3], failure of >=1 anti-cytokine (TNF and/or IL6 ihnibitor) and >=1 cell-targeted (B-cell and/or T-cell ihnibitor) bDMARD; KF-RAA, according to Kearsley-Fleet [2], exposed to >=3 bDMARDs classes; DH-RRA, according to de Hair [1], signs and/or symptoms suggestive of inflammatory RA activity (in the study we assumed DAS28>=3.2 or extra-articular manifestations) and failure of >=1 csDMARD and >=2 bDMARDs. Agreement was measured with Cohen’s kappa. To assess variables independently associated with RRA, multivariate regression analysis was used including variables achieving p Results Patients included in the study were 572. B-RRA was observed in 165 (28.8%), KF-RRA in 96 (16.8%) and DH-RRA in 57 (10.0%). DH-RRA was the most stringent definition. Agreement between the definition was fair: DH-RRA and B-RRA kappa=0.330, p Conclusion RRA was observed in a 20-30% of RA patients, slightly higher compared to previous evidence [1,2]. Characteristics of patients fulfilling different RRA definitions are diverse. Particularly, disease severity (disease activity and structural damage) was not associated with RRA if the definition considers only the exposure to bDMARDs. Given the large time span of the study period, RRA patients were more frequently those who started bDMARDs in earlier years. References [1] de Hair MJH, et al. Rheumatology2018;57:1135-1144. [2]. Kearsley-Fleet L, et al. Ann Rheum Dis 2018;77:1405–1412. [3] Buch MH. Ann Rheum Dis 2018;77:966–969. Disclosure of Interests None declared