ACR and EULAR Endorse New Boolean-Based Criteria for RA Remission

The new Boolean-based criteria improves agreement with existing index-based remission criteria and classifies more patients with rheumatoid arthritis (RA) as in remission, while continuing to predict radiographic and functional outcomes, according to study findings published in Arthritis Rheumatology.

The American College of Rheumatology (ACR) and the European Alliance of Associations for Rheumatology (EULAR) recommended the use of both Boolean- and index-based RA remission criteria in 2011. Recent studies have suggested that a higher threshold should be used for RA remission, based on the patient global assessment (PGA).

Researchers analyzed the agreement between Boolean- and index-based RA remission criteria using data from 4 randomized trials, which were conducted to assess the efficacy of biologic disease-modifying antirheumatic drugs (bDMARDs) vs methotrexate or placebo in a combined cohort of 2048 patients with RA. The majority of patients (n=1101) had early RA and the remaining had established RA.

Indexes included the Simplified Disease Activity Index (SDAI) and the Clinical Disease Activity Index (CDAI).

The researchers also studied how well scores indicating RA remission on the indexes predicted stabilization of the disease, based on lack of radiographic progression, as well as good physical function, based on Health Assessment Questionnaire (HAQ) scores of 0.5 or less.

The researchers adjusted and compared the Boolean thresholds from the original 1 cm (Boolean 1.0) to 2 cm (Boolean 2.0) on the PGA.

After 6 months following bDMARD treatment initiation, a greater number of patients — both with early and established RA — achieved disease remission using Boolean 2.0 compared with 1.0 (early RA, 20.6% vs 14.8%; established RA, 6.0% vs 4.2%).

Researchers observed increased agreement between the SDAI- and CDAI-defined remission and Boolean 2.0 compared with Boolean 1.0, especially for patients with early RA (early RA, 95.9% vs 93.4%; established RA, 98.2% vs 98.0%). In addition, SDAI, CDAI, and Boolean 2.0 similarly predicted radiographic stabilization (nonprogression) of RA and better functional outcomes according to the HAQ after 1 year of treatment.

“Using the Boolean 2.0 criteria classifies more patients as achieving remission and increases the agreement with index-based remission criteria without jeopardizing predictive value for radiographic or functional outcomes,” the study authors said. “This revised Boolean definition and the previously provisionally endorsed index-based criteria were endorsed by ACR and EULAR.”