Background/Purpose: The patient global assessment (PGA) is a core set variable to assess RA disease activity. It is strongly linked to patient-reported pain and is a limiting factor for reaching when the ACR/EULAR Boolean remission definition is used, where PGA may not be greater than 1 on a 0-10 scale. Here we assessed different PGA criteria.

Methods: We used data from six RCTs testing the efficacy of TNF inhibitors vs MTX. Included were 3 trials of early RA: ASPIRE (infliximab), Go Before (golimumab), PREMIER (adalimumab); and 3 of established RA: ATTRACT (infliximab), DE019 (adalimumab) and Go Forward (golimumab). We increased the threshold for the 0-10 score for PGA gradually by 0.5 (Boolean1.5) up to 3 (Boolean3.0), and also omitted the criterion completely (BooleanX, i.e. requiring only CRP, SJC, TJC≤1). We assessed frequencies of remission by these definitions at 6 and 12 months and evaluated agreement with the Index based (SDAI) definition of remission (which does not include an inherent cut-off for PGA). Further the impact on functional and radiographic outcomes after 1 year were explored based on achievement of each of these remission definitions at 6 months.  Using recursive partitioning (CART) we attempted to determine a PGA cut-off that optimized agreement with SDAI remission.

Results: Data from 2600 trial patients, 1680 with early RA (mean disease duration: 1.5±2.96years) and 920 with established RA (mean disease duration: 9.7±8.44 years) were included. The proportion of patients achieving Boolean remission increased with higher thresholds for PGA from 12.4% to 19.7% in early RA and 5.9% to 12.3% in established RA at 6 month and 19.9% to 30.1% and 11.4% to 22.5% respectively at 1 year. Best agreement with SDAI remission occurred at a PGA cut-off of 1.5 and 2.0, while agreement decreased with PGA thresholds of ≥ 2.5 (Figure). Compared with Boolean (using 1.0), at Boolean2.0 the number of persons who were in remission per SDAI criteria increased from 74% to 85% of all SDAI remitters at 6 months. In early RA patients evaluating data at 6 months CART analyses showed that optimal agreement with SDAI remission occurred at a PGA threshold between 1.4 and 1.7cm.

Changing PGA thresholds at 6 months did not affect radiographic outcome with scores similar across different thresholds (mean ꙙsmTSS for Boolean, 1.5, 2.0, 2.5, 3.0 and BooleanX were: 0.35±5.4, 0.38±5.14, 0.41±5.1, 0.37±4.9, 0.34±4.9 and 0.27±4.7). However, for both early and late RA, the lower the PGA threshold, the lower the HAQ score. The proportion attaining HAQ≤0.5 was 90.2%, 87.9%, 85.2%, 81.1%, 80.7% and 73.1% for Boolean, 1.5, 2.0, 2.5, 3.0 and BooleanX respectively. Omitting PGA was associated with much worse functional outcomes.

Conclusion: Increasing the PGA cut-off to 1.5cm would provide highest consistency between Boolean with the Index based remission; the integer cut-off of 2.0cm performed similarly and would also allow the use of numerical rating scales. This new cut-off discounts the excessive stringency of the current PGA cut-off in the remission context, while maintaining similar functional and radiographic long-term outcomes.

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ACR Meeting Abstracts - https://acrabstracts.org/abstract/testing-different-thresholds-for-patient-global-assessment-in-defining-acr-eular-boolean-remission-criteria-for-ra/