RT Journal Article SR Electronic T1 Effect of Concomitant Disease-modifying Antirheumatic Drugs and Methotrexate Administration Route on Biologic Treatment Durability in Rheumatoid Arthritis: OBRI Cohort Results JF The Journal of Rheumatology JO J Rheumatol FD The Journal of Rheumatology SP jrheum.180486 DO 10.3899/jrheum.180486 A1 Arthur N. Lau A1 J. Carter Thorne A1 Mohammad Movahedi A1 Emmanouil Rampakakis A1 Angela Cesta A1 Xiuying Li A1 Sandra Couto A1 John Sampalis A1 Claire Bombardier A1 the OBRI Investigators YR 2019 UL http://www.jrheum.org/content/early/2019/04/09/jrheum.180486.abstract AB Objective Prior studies have suggested that concurrent conventional synthetic disease-modifying antirheumatic drug (csDMARD) therapy enhances the efficacy of biologic DMARD (bDMARD). Here, we assessed the effect of concomitant csDMARD use and methotrexate (MTX) route of administration on time to bDMARD discontinuation in a large Canadian (Ontario), observational, rheumatoid arthritis (RA) cohort. Methods Patients from the Ontario Best Practices Research Initiative (OBRI) who initiated bDMARD therapy and had ≥ 1 followup assessment were included. The effect of concomitant csDMARD use (primary analysis) and MTX route of administration (secondary analysis) on bDMARD discontinuation owing to (1) any reason, (2) ineffectiveness, (3) adverse events (AE), and (4) both (2) and (3), were assessed with multivariate Cox regression. Results Among the 814 patients included, 153 (18.8%) received bDMARD monotherapy and 661 (81.2%) combination csDMARD/bDMARD therapy. Over a mean followup of 1.9 years, bDMARD were discontinued in 38.7% of patients. In multivariate analysis, there was a nonsignificant trend toward lower discontinuation for the csDMARD/bDMARD group compared to bDMARD monotherapy for any reason (HR 0.76, 95% CI 0.55–1.05) and owing to ineffectiveness/AE (HR 0.73, 95% CI 0.50–1.06). Further, patients taking combination therapy had significantly lower risk of bDMARD discontinuation due to AE (HR 0.43, 95% CI 0.24–0.76). In the secondary analysis, no statistical association between MTX dose or route of administration and bDMARD durability was observed. Conclusion Concomitant csDMARD use was associated with a significantly lower hazard for bDMARD discontinuation due to AE among patients with RA followed in routine clinical practice in Ontario, Canada. Neither MTX route of administration nor dose were significant predictors of bDMARD durability.