Background/Purpose:

It has been recommended that tapering csDMARDs should be considered if a patient is in persistent remission. However, methods for tapering csDMARDs, including MTX, without RA flare have not been established. Previously, we reported that baseline RAMRIS synovitis score predicted half-dose reduction of MTX without disease flare until week 24, in an RA patient who achieved clinical remission. In this study, we extended the study duration to week 52 to determine whether baseline MRI findings can predict successful half-dose reduction of MTX for a full year.

Methods: Outpatients of our hospital’s department of rheumatology were included in this study. Inclusion criteria were as follows: diagnosis of RA based on 2010 ACR/EULAR classification criteria; achievement of clinical remission, defined by DAS28-CRP, over 4 weeks; treatment with methotrexate reduced by half according to the patient’s wishes; and availability of MRI images of the hand at the time of MTX reduction. Exclusion criteria were as follows: treatment with leflunomide or tacrolimus, tsDMARDs, or bDMARDs; or oral prednisolone > 5 mg/day. In this study, we examined DAS28-CRP until week 52 every 4–8 weeks. Disease flare was defined as DAS28-CRP of ≥ 2.3 at two sequential visits, an increase in dose of MTX, and addition of other DMARDs. MRI of the patient’s dominant wrist and second through fifth metacarpophalangeal (MCP) joints was performed using a 1.5 T whole-body MRI unit with contrast enhancement. MR images were assessed for bone erosions, synovitis, and bone marrow edema according to the original OMERACT Rheumatoid Arthritis MRI Scoring System (RAMRIS).

Results:

Fifteen patients were enrolled in this study (10 women, 5 men). We evaluated all 15 patients’ data until week 52. Mean (±SD) age, disease duration, MTX dose before reduction, and DAS28-CRP at baseline were 66.6 ± 9.8 y, 6.0 ± 3.6 y, 8.8 ± 3.4 mg/w, and 1.32 ± 0.26. Thirteen patients were positive for anti-CCP antibody and RF. Subclinical MRI inflammation was detected in all patients. Median (range) synovitis, bone edema, and bone erosion score were 2 (0–7), 0 (0–4) and 7 (1–22). Two patients experienced disease flare until week 24 and one patients after week 24. Two patients without clinical remission before week 24 had significantly higher RAMRIS synovitis scores (4.5 vs. 1.9, p < 0.05). RAMRIS bone erosion score of 3 patients experiencing disease flare until week 52 tended to be higher, and total RAMRIS score (synovitis + bone edema + bone erosion score, but not synovitis score alone) was significantly higher in these patients (18.3 vs. 8.0, p < 0.05). Analysis of the ROC curve determined that the most sensitive and specific cut-off value for total RAMRIS score was 11 (AUC = 0.917, 95% CI 0.737–1.000, p < 0.001).

Conclusion:

MRI evaluation was useful for prediction of successful dose reduction of MTX during clinical remission. In the early phase of reduction, synovitis was an important factor in disease flare, and as reduction became long-term, bone erosion was also important. We conclude that half-dose reduction of MTX in RA patients who achieve clinical remission and have low total RAMRIS scores might be a beneficial option for tapering MTX.

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ACR Meeting Abstracts - https://acrabstracts.org/abstract/low-grade-total-rheumatoid-arthritis-mri-scoring-system-can-predict-successful-half-dose-reduction-of-mtx-in-patients-with-ra-in-clinical-remission/