Background The American College of Rheumatology/European League Against Rheumatism (ACR/EULAR) remission criteria (Boolean criteria) for rheumatoid arthritis (RA) is one of popular index for remission. This index is well known, but not being used even for rheumatologist, because of lack of regularity in patient’s global assessment (PGA), which is a part of the core set in Boolean criteria(1).

Objectives To evaluate near miss of Boolean criteria what means fulfilling three of the four Boolean criteria parameters in clinical practice.

Methods Since August 2010, we have been treated RA with identical protocol according to T2T recommendations. Five thousand times from 384 RA patients have had chance to measure RA disease activity index such as clinical disease activity index (CDAI), simplified disease activity index (SDAI), Boolean criteria, pain score (PS), and health assessment questionnaire (HAQ-DI). From these indices, Boolean criteria, SDAI, PS, and HAQ-DI were used in this study. Three parameters without PGA fulfilled in Boolean criteria and remission were picked up. These evaluations were qualified as SDAI criteria at each measured time. Distribution of SDAI evaluation criteria was calculated. Measured evaluation was classified into groups according to PGA increment with 1.0 on scale. SDAI remission probability, sensitivity and specificity for SDAI remission were calculated for each division. Average SDAI, average PS, and average HAQ-DI were also calculated for each division, and evaluated with linear regression analysis.

Results SDAI remission probability for each PGA division was 1.0, 0.97, 0.88, 0.55, 0.67, 0.51, and 0.49, while sensitivity for SDAI remission was 1.0, 0.9981, 0.9842, 0.9671, 0.9437, 0.9353, 0.9194, and specificity was 0.5051, 0.5556, 0.6907, 0.7214, 0.8659, 0.9048, 1.0 for 0, 0.5, 1.0, 1.5, 2.0, 2.5, 3.0 in PGA scale division, respectively. PGA was closely correlated with all of SDAI, PS and HAQ-DI significantly, while regression formula was y=0.5765x + 0.155 (R=0.99283), y=4.522x - 2.3955 (R=0.98530), and y=0.6611x – 0.0463 (R=0.84253), respectively.

Conclusions These results suggested that PGA in near misses of Boolean criteria reflects disease activity level very strongly. If PGA is within 2.5, both of sensitivity and specificity for SDAI remission demonstrated more than 90%. PGA is also closely related with pain and ADL. We should make consideration to use Boolean criteria with alternative utility.

References

1. Studenic P., et al., Ann Rheum Dis 2012;69:1702-1705

Disclosure of Interest None Declared