Real-world utilization of DMARDs and biologics in rheumatoid arthritis: the RADIUS (rheumatoid arthritis disease-modifying anti-rheumatic drug intervention and utilization study) study

Objective: Rheumatoid Arthritis (RA) Disease-Modifying Anti-Rheumatic Drug (DMARD) Intervention and Utilization Study (RADIUS) is a unique, real-world, prospective, 5-year, observational study of over 10 000 patients with RA. RADIUS provides a snapshot of use patterns, effectiveness, and safety of DMARDs, biologics, and combination therapies used to manage RA in clinical practice. Research design and methods: Patients with RA requiring a new DMARD or biologic (addition or switch) were eligible for the RADIUS study. Two separate patient cohorts were enrolled; RADIUS 1 patients initiated any new therapy at entry, and RADIUS 2 patients initiated etanercept at entry. Patient demographics and disease activity measures were collected at study entry, and baseline characteristics were summarized for various subgroups. Effectiveness, safety, and patterns of use will be tracked for therapies utilized during the 5-year study. Results: RADIUS 1 enrolled 4959 patients, and RADIUS 2 enrolled 5102 patients, mostly at community private practices (88%). In RADIUS 1, most patients initiated methotrexate (MTX) monotherapy, followed by MTX in combination with a biologic (e.g. infliximab plus MTX) or other DMARD. In RADIUS 2, most patients initiated etanercept in combination with MTX, followed by etanercept monotherapy. When a new therapy was required, physicians tended to add another therapy versus switching therapies. Patients initiating a biologic had a longer duration of RA and more severe disease compared with patients initiating non-biologic therapy. Conclusions: These real-world data provide evidence of the prescribing practices of rheumatologists in 2001-2003. Future analyses will allow evidence-based comparisons of the long-term safety and effectiveness of DMARDS, biologics, and combination therapies to assist physicians in clinical decision-making.