For patients with early axial spondyloarthritis (axSpA), the modified Stoke Ankylosing Spondylitis Spine Score (mSASSS) and the Radiographic AS Spinal Score (RASSS) captured the most structural change, and the mSASSS demonstrated the best overall performance in depicting spinal damage when using the OMERACT filter, according to findings published in Rheumatology.

Accurate evaluation of structural damage is invaluable to clinicians for its therapeutic and prognostic utility in axSpA patient care. However, the various available scoring methods have yet to be assessed and compared in early disease. Investigators sought to fill this knowledge gap to enable prevention or reduction of disease progression.

Three blinded readers examined baseline, 2- and 5-year spinal radiographs of patients enrolled in the DESIR cohort, calculating scores for the SASSS, mSASSS, RASSS, and 2 forms of the Bath Ankylosing Spondylitis Radiology Index (BASRI). Scores were then compared using the OMERACT filter in terms of feasibility, truth, and discrimination (sensitivity and reliability).


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A total of 699 participants (47% men; mean age, 34 years; mean symptom duration, 1.5 years; 59% HLA-B27-positive) were included in the study. At 5 years, researchers found net changes >1 of: RASSS, 17%; mSASSS, 12%; BASRI-spine and BASRI-total, 9%; and SASSS, 11%.The RASSS and mSASSS outperformed the other indices in terms of signal capture related to noise.

Variance proportion due explained by the patient was also highest for the RASSS and the mSASSS (85% for each at 5 years vs 50%-55% for SASSS and BASRI). Variance proportion in the thoracic section of the RASSS was unsatisfactory, with only 46% for 5-year progression. Overall, the lumbar segment showed progression more often than the cervical or thoracic sections.

Study strengths included large sample size, systematic prospective follow-up, and the use of 3 separate and blinded readers.

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Study limitations included exclusion of some patients as a result of follow-up loss or incomplete spinal segments and generally low levels of participant structural damage that hampered cross-method comparisons.

The authors concluded that, “according to the feasibility, discrimination and truth of the OMERACT filter, the mSASSS is the method most valid, feasible and sensitive to change to assess radiographic damage in all patients with axSpA, including those with early disease.”

An unrestricted grant from Pfizer was allocated for the 10 years of follow-up.

Reference

Ramiro S, Claudepierre P, Soprano A, et al. Which scoring method depicts spinal radiographic damage in early axial spondyloarthritis best? Five-year results from the DESIR cohort [published online July 23, 2018]. Rheumatology (Oxford). doi:10.1093/rheumatology/key185