The susceptibility of attaining and maintaining DMARD-free remission in different (rheumatoid) arthritis phenotypes

Objectives: To compare (sustained) DMARD-free remission rates((S)DFR), defined as respectively ≥6 months and >1 year, after 2 and 5 years between three clinical arthritis phenotypes; undifferentiated arthritis(UA), autoantibody-negative(RA-) and positive rheumatoid arthritis(RA+).

Methods: All UA(n = 130), RA-(n = 176) and RA + (n = 331) patients from the tREACH trial, a stratified single-blinded trial with a treat-to-target approach, were used. (S)DFR comparisons between phenotypes after 2 and 5 years were performed with Logistic regression. Medication use and early and late flares(DAS ≥ 2.4), respectively defined as < 12 and >12 months after reaching DFR, were also compared. Cox proportional hazard models were used to evaluate potential predictors for (S)DFR.

Results: Within 2 and 5 years less DFR was seen in RA + (17.2-25.7%), followed by RA-(28.4-42.1%) and UA patients(43.1-58.5%). This also applied for SDFR within 2 and 5 years (respectively 7.6% and 21.4%; 20.5% and 38.1%; and 35.4% and 55.4%). A flare during tapering was seen in 22.7% of patients. Of the patients in DFR 7.5% had an early flare and 3.4% a late flare. Also more treatment intensifications occurred in RA+ compared with RA- and UA. We found that higher baseline DAS, ACPA positivity, BMI and smoking were negatively associated with (S)DFR, while clinical phenotype(reference RA+), short symptom duration(<6 months) and remission within 6 months were positively associated.

Conclusions: (Long-term) clinical outcomes differ between undifferentiated arthritis, autoantibody-negative and positive rheumatoid arthritis(RA). These data reconfirm that RA can be subdivided into aforementioned clinical phenotypes and that treatment might be stratified upon these phenotypes, although validation is needed.

Trial registration: ISRCTN, https://www.isrctn.com/, ISRCTN26791028.