With remission in rheumatoid arthritis (RA) an increasingly attainable goal, there is no widely used definition of remission that is stringent but achievable and could be applied uniformly as an outcome in clinical trials.

A committee consisting of members of the American College of Rheumatology, the European League Against Rheumatism and the Outcome Measures in Rheumatology Initiative (OMERACT) met to guide the process and review prespecified analyses from clinical trials of patients with RA. The committee requested a stringent definition (little, if any, active disease) and decided to use core set measures to define remission including at least joint counts and an acute phase reactant. Members were surveyed to select the level of each core set measure consistent with remission. Candidate definitions of remission were tested including those that constituted a number of individual measures in remission (Boolean approach) as well as definitions using disease activity indexes. To select a definition of remission, trial data were analyzed to examine the added contribution of patient reported outcomes and the ability of candidate measures to predict later good x-ray and functional outcomes.

Survey results for the definition of remission pointed to indexes at published thresholds and to a count of core set measures with each measure scored as 1 or less (e.g. tender and swollen joint counts, CRP and global assessments on 0-10 scale). Analyses suggested the need to include a patient reported measure. Examination of 2 year follow-up data suggested that many candidate definitions performed comparably in terms of predicting later good x-ray and functional outcomes, although DAS28 based measures of remission did not predict good radiographic outcomes as well as did the other candidate definitions. Given these and other considerations, we propose that a patient be defined as in remission based on one of two definitions : 1: When their scores on the following measures are all <1: tender joint count, swollen joint count, CRP (in mg/dL) and patient global assessment (0-10 scale), OR 2: when their score on the SDAI is < 3.3.

We propose two new definitions of remission both of which can be uniformly applied and widely used in RA clinical trials. We recommend that one of these be selected in each trial as an outcome and that the results on both be reported in each trial.