Background/Purpose:

In the ACR/EULAR criteria remission can be defined in two ways, either by fulfilment of 4 Boolean criteria or by a Simplified Disease Activity Index (SDAI) score ≤ 3.3. Failure to fulfill the patient global disease activity (PGA) score < 1 cm criterion in the Boolean version has been shown to be the major determinant of “near misses” of remission in established RA. It is not known if this factor is of the same importance when RA patients are identified and treated at a very early stage. The purpose of this study was to investigate the role of PGA in fulfilment of the ACR/EULAR remission criteria after 2 years in patients with RA in a very early arthritis clinic.

Methods:

Patients with arthritis of <16 weeks' duration were included in an early arthritis cohort from 2004-2010 and followed for 2 years with a comprehensive data collection. Patients were treated according to current clinical practice and not with a structured treat-to-target approach. Patients with RA according to the 2010 classification criteria with 2 years follow-up time were included in the present analysis. Frequency of 2-year remission was calculated according to both versions of the criteria, as well as which criterion was not fulfilled in patients fulfilling 3/4 Boolean criteria. 

Results:

Of 1086 very early arthritis patients included, 185 (17.0 %) had RA according to the 2010 criteria at inclusion and had 2-year data on Boolean remission (mean (SD) age 52.5 (13.8) years, n (%) females 112 (60.5), median (25-75 percentile) duration of symptoms at inclusion 63 (40-83)). 171 of these patients had data on SDAI remission. After 2 years, 41/185 (22.2 %) were in Boolean remission, while 65/171 (38.0 %) were in SDAI remission. 63 patients (34.5 %) fulfilled 3 of the Boolean criteria (criterion not fulfilled: PGA n=52, CRP n=5, TJC n=3, SJC n=1, missing data n=2). If the PGA cut-off was raised to ≤2, the remission rate increased to 61/185 (33.0 %). A PGA cut-off of ≤ 3 gave a remission rate of 72/185 (38.9 %). Omitting the PGA criterion, the remission rate was 93/185 (50.3 %).  Mean (range) PGA score in the 52 patients failing to fulfill the criteria due to elevated PGA was 3.5 (1.1-8.9). 44/52 (84.6 %) of patients with PGA > 1 had evaluator’s global disease activity (EGA) ≤ 1; 25 of these 44 (56.8 %) were in SDAI remission. 13 patients who were not in ACR/EULAR Boolean remission fulfilled the PGA criterion.

 

Conclusion:

In this very early arthritis clinic only 22% of early RA patients were in ACR/EULAR Boolean remission after 2 years of follow-up, while 38 % were in remission according to SDAI. Elevated PGA was the major reason for not being in remission in patients fulfilling 3/4 of the Boolean remission criteria, and in the majority of these patients EGA was ≤ 1. A PGA cut off of ≤ 3 resulted in a similiar remission rate (38.9 %) as with the index based (SDAI) remission definition. 

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ACR Meeting Abstracts - https://acrabstracts.org/abstract/the-role-of-patient-global-disease-activity-score-in-the-definition-of-american-college-of-rheumatologyeuropean-league-against-rheumatism-remission-in-very-early-rheumatoid-arthritis-from-the-n/