Early rheumatoid factor decline predicts subsequent clinical remission in rheumatoid arthritis: the ANSWER cohort

Abstract Objectives To compare early changes in RF across classes of biological or targeted synthetic DMARDs (b/tsDMARDs) and assess whether early RF decline was associated with 12-month clinical remission in RA. Methods We retrospectively analysed 1423 newly initiated b/tsDMARD treatment courses from the multicentre ANSWER cohort that continued for ≥12 months and had RF measured at baseline and 3 months. Early RF decline was defined as a ≥20% reduction at 3 months. Multivariable regression assessed factors associated with RF change and 12-month Clinical Disease Activity Index (CDAI) remission. Twelve-month remission rates were also compared across four categories of RF reduction. Results RF reduction differed across classes, with Janus kinase inhibitors (JAKi) showing the greatest decline. Compared with TNF inhibitors (TNFi), JAKi were associated with a greater RF reduction (β = −14.50, 95% CI: −20.04 to −8.97; P  Conclusion Early RF decline differed across b/tsDMARD classes and was associated with 12-month remission. Longitudinal RF dynamics may provide clinically useful prognostic information in RA.