Early rheumatoid arthritis, two distinctive structural damage patterns revealed by MRI: an 8-year longitudinal study

To determine how inflammatory and structural parameters change long-term on standard treatment in rheumatoid arthritis patients and which baseline parameter best predicts long-term structural damage.

Prospective study of early rheumatoid arthritis (ERA) patients (symptom duration ≤ 24 months) who underwent identical clinical, serological, radiographic, and dynamic contrast-enhanced MRI of the wrist assessments at baseline, year-1, and year-8. MR images were analyzed semi-quantitatively (Rheumatoid Arthritis Magnetic Resonance Imaging Score [RAMRIS]) and quantitatively (synovial volume (cm³); synovial perfusion; bone marrow edema (BME) proportion [%]). Multivariate analyses and receiver operating curves were applied to find the best predictor of long-term structural damage.

81 patients (61 ± 12 years, F/M:67/14) were studied. MRI-detected inflammatory parameters markedly improved from baseline to year-1 and slightly deteriorated from year-1 to year-8 (synovial volume:6.7 ± 5.0→2.6 ± 2.9→3.6 ± 3.3 cm³ (p < 0.01); BME proportion:13.1 ± 9.3→7.4 ± 5.0→9.2 ± 9.7% [p < 0.01]). Structural damage progressively deteriorated from baseline to year-8. Two long-term structural damage pattern groups were apparent, namely a "non-progressive structural damage pattern" (62%, 50/81) and a "progressive structural damage pattern" (38%, 31/81). Functional impairment was more frequent and more severe at year-8 in patients with progressive structural damage. MRI-detected bone erosion score better predicted (AUC = 0.81, CI: 0.71-0.91) year-8 structural damage than clinical (SDAI AUC = 0.61, CI: 0.48-0.74), serological (CRP AUC = 0.60, CI: 0.47-0.73), or radiographic (AUC = 0.59, CI: 0.45-0.72) assessment.

In ERA patients, two distinct structural damage patterns are evident. Baseline bone erosion score is better than clinical, serological, or radiographic assessment at predicting long-term structural damage.

Questions The value of MRI in predicting long-term structural damage in ERA patients is not clear. Findings This study identified two distinct long-term structural damage progression patterns of ERA patients. MRI can better differentiate between these two groups at baseline than clinical, serological, or radiographic assessment. Clinical relevance MRI examination should be performed in all ERA patients at baseline to determine their structural damage pattern. This will allow a better prediction of patient outcomes in the long-term.