Objectives. To assess any association between bone marrow oedema on MRI of the sacroiliac joints (MRI-SIJ) according to local readings in daily practice and the development of structural damage on radiographs of the SIJ (X-SIJ) in axial spondyloarthritis (axSpA). Methods. Patients with axSpA from the Assessment of the SpondyloArthritis international Society (ASAS) and DEvenir des Spondylarthopathies Indifférenciées Récentes (DESIR) multicentre cohorts were included. MRI-SIJ and X-SIJ were obtained at baseline, and X-SIJ at follow-up after a mean 4.6 years (ASAS) and 5.1 years (DESIR). All images were scored by local readers. Structural damage in the X-SIJ was defined according to the modified New York criteria. The percentage of structural net progression (number of 'progressors' minus the number of 'regressors' divided by the total number of patients) was assessed and the effect of bone marrow oedema on MRI-SIJ on X-SIJ damage evaluated by multivariable logistic regression. Results. In total, 125 (ASAS-cohort) and 415 (DESIR-cohort) patients had baseline MRI-SIJ and complete X-SIJ data available. According to local readings, progression and 'improvement' in X-SIJ was seen in both the ASAS- and DESIR-cohort, yielding a net progression that was higher in the former than in the latter (19.2% and 6.3%). In multivariable analysis, baseline bone marrow oedema on MRI-SIJ was strongly associated with X-SIJ structural progression in both ASAS (odds ratio = 3.2 [95% CI: 1.3; 7.9]), and DESIR (odds ratio = 7.6 [95% CI: 4.3; 13.2]). Conclusion. Inflammation on MRI-SIJ is associated with future radiographic progression according to local readings despite an expected increased imprecision invoked by local readings.
- Axial spondyloarthritis
- Structural damage