Advantages of a combined rheumatoid arthritis magnetic resonance imaging score (RAMRIS) for hand and feet: does the RAMRIS of the hand alone underestimate disease activity and progression?

Background: To evaluate a combined rheumatoid arthritis magnetic resonance imaging score (RAMRIS) for hand and foot (HaF-score) in rheumatoid arthritis (RA). Methods: Magnetic resonance imaging (MRI, 0.2 Tesla) of the dominant hand and foot of 26 ACPA positive RA patients before and 6 months after initiation of methotrexate was obtained. RAMRIS of the hand was complemented by corresponding scoring of the foot (MTP I-V; HaF-score). Disease Activity Score 28 (DAS28) and a tender and swollen joint count (JC) of the joints scored in MRI were recorded. Changes in these scores (Delta) were assessed. Results: Delta HaF-score correlated significantly with Delta DAS28 (r = 0.820, 95%-CI 0.633-0.916). Correlations to Delta DAS28 were best for changes in the synovitis subscore (0.648) and bone marrow edema (0.703). Correlations to Delta DAS28 were significantly better for of the Delta HaF-score than Delta RAMRIS (0.499, 0.139-0.743, p = 0.0368). All patients with at least moderate response (EULAR criteria, n = 11) had continuing disease activity on MRI, including five cases with new erosions, three of them at the feet. Improvements of the hand JC or foot JC were seen in 16 and 15 cases, respectively. However, MRI of the hand or feet improved in only 10 and 9 cases, respectively. No patient fulfilled SDAI remission criteria. Conclusions: The HaF-score identifies patients with continuing disease activity despite clinical response that would have been missed by consideration of the traditional RAMRIS or the DAS28 alone. Response as opposed to remission may be an insufficient goal in RA as all patients showed continuing disease activity, especially at the feet.