SAT0378 THE RELATIVE DIAGNOSTIC UTILITY OF INFLAMMATORY BACK PAIN CRITERIA IN AN INCEPTION COHORT OF PATIENTS WITH PSORIASIS, IRITIS, AND COLITIS PRESENTING WITH UNDIAGNOSED BACK PAIN
Authors: G. Kröber, U. Weber, R. Carmona, J. Yeung, J. Chan, S. Aydin, L. Martin, A. Masetto, S. Keeling, O. Ziouzina, S. Rohekar, R. Dadashova, J. Paschke, A. Carapellucci, R. G. Lambert, W. P. Maksymowych
Journal: Annals of the Rheumatic Diseases (2020)

Background: Clinicians rely on the elicitation of features of inflammatory back pain (IBP) for diagnosis of axial spondyloarthritis (axSpA) but the utility of IBP criteria in patients presenting with extra-articular features of axSpA remains unclear. Assessment of utility should include not only rheumatologist diagnosis as benchmark but imaging to address the circularity between elicitation of IBP and clinical diagnosis. Objectives: To assess the diagnostic utility of all criteria for IBP in patients with psoriasis, iritis, or colitis and undiagnosed back pain using the rheumatologist diagnosis and imaging as benchmarks. Methods: Consecutive patients (n=246) with undiagnosed back pain ≤45 years of age, ≥3 months, with any one of psoriasis (n=46), acute anterior uveitis (AAU)(n=73), or colitis (n=127) had diagnostic evaluation by a rheumatologist. Majority central reader assessment of MRI indicative of axSpA and diagnosis by the rheumatologist were external standards for testing the utility of these IBP criteria: ASAS, Berlin, Calin, rheumatologist global for IBP &gt;5 (0-10 scale). Results: AxSpA was diagnosed in 44.4%, 61.6%, and 41.8% of patients with psoriasis, iritis, and IBD, respectively. Diagnostic utility for all IBP criteria was comparably poor (Table 1). MRI was indicative of axSpA in 21.2%, 43.5%, and 19.7% of patients with psoriasis, iritis, and IBD. The utility of the IBP criteria was even worse using MRI as the external reference (Table 2), especially in patients with psoriasis. Only 14% of psoriasis patients with a positive MRI reported “improvement with exercise but not rest” as compared to 70% and 62% of patients with iritis and IBD, respectively. Table 1. Rheumatologist diagnosis as external reference. Sensitivity Specificity LR+ LR - Psoriasis ASAS IBP 65.00% 52.00% 1.35 0.67 Berlin IBP 80.00% 36.00% 1.25 0.56 Calin IBP 80.00% 28.00% 1.11 0.71 All 3 criteria sets 60.00% 56.00% 1.36 0.71 IBP global &gt;5 85.00% 36.00% 1.33 0.42 AAU ASAS IBP 84.44% 42.86% 1.48 0.36 Berlin IBP 80.00% 57.14% 1.87 0.35 Calin IBP 93.33% 17.86% 1.14 0.37 All 3 criteria sets 77.78% 60.71% 1.98 0.37 IBP global &gt;5 86.67% 57.14% 2.02 0.23 IBD ASAS IBP 78.43% 45.07% 1.43 0.48 Berlin IBP 82.35% 52.11% 1.72 0.34 Calin IBP 84.31% 19.72% 1.05 0.80 All 3 criteria sets 70.59% 57.75% 1.67 0.51 IBP global &gt;5 80.39% 66.20% 2.38 0.30 Table 2. Central assessment that MRI is indicative of axSpA as external reference. Sensitivity Specificity LR+ LR - Psoriasis ASAS IBP 28.57% 38.46% 0.46 1.86 Berlin IBP 42.86% 15.38% 0.51 3.71 Calin IBP 71.43% 23.08% 0.93 1.24 All 3 criteria sets 14.29% 42.31% 0.25 2.03 IBP global &gt;5 85.71% 23.08% 1.11 0.62 AAU ASAS IBP 75.00% 26.92% 1.03 0.93 Berlin IBP 70.00% 38.46% 1.14 0.78 Calin IBP 90.00% 15.38% 1.06 0.65 All 3 criteria sets 65.00% 38.46% 1.06 0.91 IBP global &gt;5 75.00% 38.46% 1.22 0.65 IBD ASAS IBP 92.31% 37.74% 1.48 0.20 Berlin IBP 76.92% 39.62% 1.27 0.58 Calin IBP 92.31% 16.98% 1.11 0.45 All 3 criteria sets 76.92% 45.28% 1.41 0.51 IBP global &gt;5 92.31% 47.17% 1.75 0.16 Conclusion: All IBP criteria have poor diagnostic utility for diagnosis of axSpA, especially in patients with psoriasis. This reinforces the desirability of less subjective assessment tools, especially imaging. Disclosure of Interests: Georg Kröber: None declared, Ulrich Weber: None declared, Raj Carmona: None declared, James Yeung: None declared, Jon Chan: None declared, Sibel Aydin: None declared, Liam Martin: None declared, Ariel Masetto: None declared, Stephanie Keeling: None declared, Olga Ziouzina: None declared, Sherry Rohekar: None declared, Rana Dadashova: None declared, Joel Paschke: None declared, Amanda Carapellucci: None declared, Robert G Lambert: None declared, Walter P. Maksymowych Grant/research support from: AbbVie, Novartis, Pfizer, and UCB, Consultant of: AbbVie, Boehringer Ingelheim, Celgene, Eli Lilly, Galapagos, Janssen, Novartis, Pfizer, and UCB, Employee of: Chief Medical Officer of CARE Arthritis Limited, Speakers bureau: AbbVie, Janssen, Novartis, Pfizer, and UCB