Evaluation of different methods used to assess disease activity in rheumatoid arthritis: analyses of abatacept clinical trial data

OBJECTIVES To evaluate different methods of reporting response to treatment or disease status for their ability to discriminate between active therapy and placebo, or to reflect structural progression or patient satisfaction with treatment using an exploratory analysis of the Abatacept in Inadequate Responders to Methotrexate (AIM) trial. METHODS 424 active (abatacept approximately 10 mg/kg) and 214 placebo-treated patients with rheumatoid arthritis (RA) were evaluated. METHOD of reporting included: (1) response (American College of Rheumatology (ACR) criteria) versus state (disease activity score in 28 joints (DAS28) criteria); (2) stringency (ACR20 vs 50 vs 70; moderate disease activity state (MDAS; DAS28 <5.1) vs low disease activity state (LDAS; DAS28 or=2). More stringent criteria (at least ACR50/LDAS), faster onset (3 visits) of ACR50/LDAS best reflected patient satisfaction (positive LR >10). CONCLUSIONS The optimal method for reporting a measure of disease activity may differ depending on the outcome of interest. Time to onset and sustainability can be important factors when evaluating treatment response and disease status in patients with RA.