Abstract
OBJECTIVES: Radiographic erosions of hands and feet are a hallmark of rheumatoid arthritis (RA) and treatment aims to prevent radiographic progression. In the at-risk phase of clinically suspect arthralgia (CSA), erosions on radiographs are rare but can be visible on MRI, which is a more sensitive imaging technique. However, the value of these MRI erosions and especially the relation with radiographic erosions is unknown. Therefore, we aimed to study if MRI-detected erosions in CSA (i) correspond with simultaneous radiographic erosions and (ii) associate with local radiographic progression. METHODS: Patients included in the Leiden CSA cohort (2012-2021) were followed until RA development or for 2 years. Unilateral hand-and-foot baseline MRIs were scored for erosions (RAMRIS score ≥ 1) and subclinical inflammation (synovitis/tenosynovitis/osteitis). Serial hand and foot radiographs (baseline, 12 and 24 months) were scored for erosions [Sharp-van-der-Heijde erosion-score (SHS) ≥1] and progression (delta-SHS ≥ 1). Generalized estimating equation evaluated if MRI erosions associated with radiographic erosions or progression in the same bone. Additionally, analyses were repeated considering concomitant MRI-detected subclinical inflammation. RESULTS: A total of 190/405 CSA patients (47%) had MRI-detected erosions at one or more of the 23 studied bone locations. An MRI-detected erosion associated with a local radiographic erosion [OR 5.23 (95%CI2.78-9.86)]; but in 96.5% of locations with an MRI-detected erosion a radiographic erosion was absent. MRI erosions with concomitant local subclinical inflammation revealed a stronger association [OR 6.29(2.94-13.48)]. Local radiographic progression was rare (0.4%). MRI erosions at baseline did not predict radiographic progression [OR 1.75(0.52-5.85)]. CONCLUSION: The majority of MRI-detected erosions in CSA patients does not correspond with radiographic erosive disease or progression. Therefore, MRI-detected erosions in this risk phase, especially without inflammation, should be regarded with caution to avoid overinterpretation.