Session Type: Abstract Submissions (ACR)
Background/Purpose Vertebral corner fat lesions have been shown to be associated with later development of new syndesmophytes in the same vertebral corners1,2. The aim of this study was to investigate the association between fat lesions and radiographic progression at the patient level using the novel Fat Spondyloarthritis Spine Score (FASSS)3. This could lead to an important target for therapeutic intervention..
Methods 157 patients with AS (N (%) male sex: 121 (77%); receiving TNFα inhibitor: 93 (59%); mean (SD) age: 39.4 (11.7); symptom duration: 15.9 (10.2)) had MRIs and X-rays performed with a mean (SD) follow-up of 2.3 (0.7) years and 2.2 (0.68) years. Status and change in fat lesions were assessed with FASSS and radiographic progression with the modified Stoke AS Spine Score (mSASSS). Two readers independently read MRIs scans and radiographs, and an adjudicator re-assessed discrepant cases according to pre-specified rules. Multivariate stepwise regression analysis included variables significant in univariate analyses (age, sex, symptom duration, baseline CRP, baseline mSASSS) and treatment.
Results When mSASSS progression was dichotomized (mSASSS progression yes/no), baseline FASSS scores were significantly higher in the progression group as compared to the non-progression group (20.0 (21.6) vs. 12.9 (22.5), p<0.001). When a pre-specified FASSS cut-off of 5 was used, which has been suggested as a definition of a "positive spine MRI"4, higher rates of radiographic progression were seen in patients with score ≥5 vs. <5 (1.19 (1.52) vs 0.34 (0.72), p<0.001). In the regression analyses baseline FASSS score was the only independent predictor of radiographic progression (β=0.008, p=0.0004). Figure 1 shows patients with a baseline FASSS scores ≥5 had a higher cumulative probability of radiographic progression.
Conclusion A positive spine MRI for fat assessed with FASSS, and the degree of spinal fat are significantly associated with radiographic progression in patients with AS.
1Baraliakos X et al. Ann Rheum Dis. 2013 (online)
2Chiowchanwisawakit P et al. Arthritis Rheum. 2011;63:2215-25
3Pedersen SJ et al. Arthritis Res Ther. 2014:16:R100;
4Bennett AN et al. Ann Rheum Dis 2010;69:891-4.
S. J. Pedersen,
R. G. Lambert,
W. P. Maksymowych,
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ACR Meeting Abstracts - https://acrabstracts.org/abstract/the-fat-spondyloarthritis-spine-score-fasss-independently-predicts-radiographic-progression-in-patients-with-ankylosing-spondylitis/