Session Type: Poster Session (Sunday)
Session Time: 9:00AM-11:00AM
Background/Purpose: xThe ASAS classification criteria for axial spondyloarthritis (axSpA) have overall sensitivity/specificity of 82.9%/84.4% but component imaging and clinical arms differ in performance (66.2%/97.3% and 56.6%/83.3%, respectively). We aimed to demonstrate that a data-driven elimination of SpA clinical features that were non-discriminatory in comparisons of patients diagnosed with and without axSpA in a prospective cohort of unselected patients with undiagnosed back pain could enhance the performance of the criteria.
Methods: We used data from the prospective multicenter Screening for Axial Spondyloarthritis in Psoriasis, Iritis, and Colitis (SASPIC) Study, which is aimed at early detection of axial SpA in patients referred by the respective specialist after first presenting with these disorders. Consecutive patients ≤45 years of age with ≥3 months undiagnosed back pain with any one of psoriasis, AAU, or colitis undergo routine clinical evaluation by a rheumatologist for axial SpA and MRI evaluation is ordered per rheumatologist decision. The rheumatologist determines the presence or absence of axial SpA and the degree of confidence in the diagnosis. Imaging was assessed by central readers. Univariable and multivariable logistic regression analysis was performed to determine which clinical SpA features were/were not discriminatory for the final diagnosis of axSpA. We then compared the sensitivity and specificity of the ASAS criteria with and without these features.
Results: xA total of 246 patients were recruited, 47.6% being diagnosed with axSpA (61.5% male, age 33.7 years, symptom duration 7.6 years, B27 positive 52.1%). The following clinical SpA features were non-discriminatory between axSpA/not axSpA: NSAID response, family history of SpA, heel enthesitis, peripheral arthritis, dactylitis. Specificity of the clinical arm and the overall criteria increased from 82.2% to 86.8% without impacting sensitivity. This effect was particularly noteworthy in patients with lower degree of symptomatology (back pain severity < 5/10, specificity increases from 76.7% to 90.7%), short symptom duration (< 5 years, specificity increases from 78% to 84.7%), and in females (specificity increases from 80.6% to 86.1%).
Conclusion: xIn a prospective cohort with a high pre-test probability of axSpA certain clinical SpA features were not helpful in discriminating a diagnosis of SpA from not-SpA. Deletion of these features from the list of SpA features used in the ASAS classification criteria enhanced the performance of the criteria, especially in female patients and those with early disease.
To cite this abstract in AMA style:Maksymowych W, Carmona R, Chan J, Yeung J, Aydin S, Martin L, Masetto A, Mosher D, Ziouzina O, Keeling S, Rohekar S, Dadashova R, Paschke J, Carapellucci A, Lambert R. Enhanced Performance of the ASAS Classification Criteria by Deletion of Non-Discriminatory Clinical Items: Data from the Screening in Axial Spondyloarthritis in Psoriasis, Iritis, and Colitis Cohort [abstract]. Arthritis Rheumatol. 2019; 71 (suppl 10). https://acrabstracts.org/abstract/enhanced-performance-of-the-asas-classification-criteria-by-deletion-of-non-discriminatory-clinical-items-data-from-the-screening-in-axial-spondyloarthritis-in-psoriasis-iritis-and-colitis-cohort/. Accessed January 16, 2021.
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