LEEDS, UK—The majority of rheumatoid arthritis (RA) patients who met standard criteria for remission  continued to have active inflammation, illustrated by magnetic resonance imaging (MRI)-detectable synovitis and/or bone marrow edema. "This subclinical inflammation may explain the observed discrepancy between disease activity and outcome in RA," write A. K. Brown, MD, and colleagues in Arthritis & Rheumatism.1

"The term 'true remission' should be reserved for patients who are not only in a state of clinical remission, but also show an absence of synovitis on imaging studies." —A. K. Brown, MD.
"These data support the use of imaging for accurate evaluation of disease status in patients with RA, even when clinical measures of response have normalized. We propose a model of remission that is analogous to the concept applied in other diseases and suggest that the term 'true remission' should be reserved for patients who are not only in a state of clinical remission, but also show an absence of synovitis on imaging studies," the researchers conclude.

All patients had DMARD-induced remissions

The Brown study included 107 RA patients who were taking disease-modifying antirheumatic drugs (DMARDs) and had been judged by their consultant rheumatologist to be in remission according to American College of Rheumatology (ACR) criteria, the Disease Activity Score 28-joint assessment (DAS-28), and a strict clinical definition of remission. The RA patients were compared to 17 normal control subjects.

The patients in this study were being or had been treated with conventional DMARDs (mainly methotrexate or sulfasalazine monotherapy or combination therapy). Only three had taken biologic agents, and only two were taking low-dose oral steroids.

The researchers used MRI and ultrasound to image the hands and wrists of all patients and controls. They found that, regardless of which clinical remission criteria were used, most of the patients continued to have active inflammation.

Most continue to have synovial hypertrophy, bone marrow edema

"Even in asymptomatic patients with clinically normal joints, MRI showed that 96% had synovitis and 46% had bone marrow edema, and ultrasound imaging showed that 73% had gray-scale synovial hypertrophy and 43% had increased power Doppler signal," they report. Mild synovial thickening was seen in three of the 17 control subjects (18%), but none had bone marrow edema.

Brown et al point out that synovitis in RA is a link between inflammation and structural damage and they predict that the patients in this cohort who had synovitis are at risk for subsequent structural damage. They suggest that such persistent, active synovial inflammation may explain the adverse RA outcomes seen even in patients who meet the ACR and DAS28 criteria for complete remission.

"This is a large study and needs to be taken seriously," said Professor John R. Kirwan, consultant rheumatologist and professor of rheumatic diseases at the Bristol Royal Infirmary, in the UK. Dr. Kirwan, who reviewed the study for CIAOMed, warned against over-interpretation of these data, however. "Most of the patients in this study were taking what I would consider suboptimal treatment. Only 2% were taking oral glucocorticoids in addition to their NSAIDs, although there is extremely strong evidence that they prevent x-ray progression," he said.

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Reference

1. Brown AK, Quinn MA, Karim Z, et al. Presence of significant synovitis in rheumatoid arthritis patients with disease-modifying antirheumatic drug-induced clinical remission. Evidence from an imaging study may explain structural progression. Arthritis Rheum. 2006;54:3761–3773.