Characteristics of patients with difficult-to-treat rheumatoid arthritis: a descriptive retrospective cohort study

Background In 2021, an EULAR task force published a definition of difficult-to-treat rheumatoid arthritis (D2T RA). Our current knowledge of D2T RA with the EULAR definition is based on European and Asian cohorts, and no North American cohort has yet to be published. The aim of this study was to compare D2T RA patients to non-D2T RA who are good responders to advanced therapy, and to describe their evolution in an university health center patient cohort. Methods This is a retrospective single centre study of the medical records of all adults with RA on at least one biologic or target synthetic DMARD (b/tsDMARD). D2T RA group was defined according to the EULAR definition of D2T RA. The non-D2T RA group was defined as a b/tsDMARD good responder who had low-disease activity or remission for at least one year on 1 or 2 b/tsDMARD mechanism of action. We compared the patients' comorbidities, and history of b/tsDMARD use. Descriptive statistics and proportions were calculated. Kaplan-Meier analysis with log-rank test was used to estimate and compare median survival. Results Among the 417 patients, 101 (24%) were D2T RA and 316 (76%) were non-D2T RA. D2T RA group was slightly younger (63 +/- 9 years versus 65 +/- 12 years, p = 0.045), more likely to have concomitant non-inflammatory pain (28% versus 8%, p < 0.0001) and to discontinue at least one b/tsDMARD due to intolerance (39% versus 10%, p < 0.0001). In the D2T RA group, JAK inhibitors were associated with longer drug continuation when used as the third b/tsDMARD. Fewer patients were using corticosteroid at their most recent follow-up in this Canadian cohort compared to others (16% versus from 29 to 74%). Conclusion Concomitant non-inflammatory pain was more prevalent in D2T RA patients compared to b/tsDMARD good responder non-D2T RA patients. Steroid-sparing strategies is possible even in D2T RA patients. Future prospective research may compare JAK inhibitors with other mechanisms of action in D2T RA.