Disease Activity Evident on Foot MRI During Clinical Remission in Rheumatoid Arthritis

A sizeable percentage of patients with rheumatoid arthritis (RA) who are in clinical remission have evidence of disease activity on magnetic resonance imaging (MRI) of the foot that is mostly affected, according to a study published in Rheumatology International.

The Disease Activity Score 28 (DAS28) is one of the most common measures of disease activity in RA and is frequently used to determine clinical remission. But the DAS28 does not include the foot and ankle joints — which are affected by RA at least as often as the hands and wrists — in its evaluation of 28 joints for swelling and tenderness. 

Synovitis and bone marrow edema on MRI are considered markers of subclinical inflammation, or low disease activity. Data suggest that many patients in clinical remission have MRI evidence of low disease activity in the hands and wrists. However, data are lacking regarding MRI evidence of disease activity in the feet in patients in clinical remission.

Ronaldo Garcia Rondina, MD, and colleagues, from the Federal University of Espírito Santo in Vitória, Brazil, evaluated whether patients with RA in remission, by clinical criteria, exhibit MRI evidence of disease in the clinically dominant foot. 

Of 55 patients with RA recruited from a rheumatology specialty clinic, 36.6% reported having foot pain. The majority of patients were receiving treatment with a disease-modifying antirheumatic agent (DMARD). 

Approximately 42% of patients were in clinical remission, according to the DAS28 with C-reactive protein level (DAS28-CRP) score.

In patients in clinical remission, synovitis and bone marrow edema on MRI were present in 52.1% and 56.2% of patients, respectively. Nearly 70% of patients in remission had one or both of these MRI findings.

No association between DAS28-CRP scores and MRI findings was found.

Summary and Clinical Applicability

Many patients with RA who are in clinical remission demonstrate evidence of subclinical inflammation on MRI of the hands and wrists. Until recently, data for ongoing MRI disease activity in the feet in this population were lacking. Researchers sought to determine the relationship between clinical remission and MRI disease activity in the clinically dominant foot.

“Our results demonstrate that a significant portion of patients classified as in clinical remission by DAS28 present some imaging findings suggesting disease activity (synovitis and/or bone edema) in their clinical dominant foot. These results are similar to other studies performed on MRI of the hands and wrists,” Dr Rondina told Rheumatology Advisor.

Dr Rondina indicated that future research should aim to determine whether MRI imaging should be incorporated into disease activity scores. Clinical trials are also needed to evaluate “if the treatment of these patients classified as in ‘clinical remission’ but with subclinical findings (MRI findings) would alter the course of the disease and the prognosis,” he said.

Limitations and Disclosures

Obtaining MRI imaging of only the most affected foot may have introduced bias in calculating the correlation between MRI findings and DAS28-CRP scores, since the DAS28-CRP does not include foot and ankle joints in its 28-joint evaluation.

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Reference

Rondina RG, de Mello RAF, Valim V, et al. Discordance between clinical and imaging criteria: assessment by magnetic resonance imaging of the foot of patients with rheumatoid arthritis [published online May 27, 2017] Rheumatol Int. doi:10.1007/s00296-017-3754-x