SAT0311 DIAGNOSTIC UTILITY OF INDIVIDUAL INFLAMMATORY BACK PAIN PARAMETERS IN PATIENTS WITH AXIAL SPONDYLOARTHRITIS
Authors: Manouk de Hooge, Floris A. van Gaalen, Marleen van de Sande, Karen Fagerli, Lennart Jacobsson, Dirk Elewaut, Désirée van der Heijde, Filip van den Bosch
Journal: Annals of the Rheumatic Diseases (2019)

<h3>Background:</h3> A recent study in German chronic back pain (CBP) patients (pts) with a suspicion of axial spondyloarthritis (axSpA) report on the performance of, among others, the ASAS inflammatory back pain (IBP) criteria and the individual IBP parameters. Pts were diagnosed by a rheumatologist blinded for all clinical features but IBP and by a rheumatologist with all diagnostic tests available as in daily practice (reference standard). Data show high sensitivity but low specificity of the ASAS IBP criteria and individual IBP parameters(1). Performance of IBP in other countries is less studied. <h3>Objectives:</h3> What is the diagnostic utility of IBP and the individual IBPpar according to the ASAS IBP criteria in several rheumatology settings in West- and Northern-Europe? <h3>Methods:</h3> Data of the multicentre, observational Be-Giant and SPondyloArthritis Cause Early (SPACE) cohorts were used. The Be-Giant cohort included ≥18 years old, newly diagnosed axSpA pts who were diagnosed by a rheumatologist and fulfilled the ASAS axSpA criteria. SPACE cohort included pts, ≥16 years, with (almost) daily CBP for ≥3 months and ≤2 years, with a symptom onset &lt;45 years. In SPACE, axSpA pts were diagnosed by a rheumatologist (plus a level of confidence of ≥7 on a 0–10 scale). All other pts in SPACE were labelled as 'no axSpA'. Pts underwent a diagnostic workup according to the protocol of the corresponding cohort, including data on the individual parameters of the ASAS IBP criteria. Sensitivity, specificity and positive likelihood ratios (LR+) were calculated using the axSpA pts from each cohort separately and the "no axSpA" pts as control group. <h3>Results:</h3> IBPpar data was available in 661 pts (SPACE) and 228 pts (Be-Giant); 36.0% and 49.6% were male, mean age 30.8±8.2 and 34.7±9.7 years, respectively. The figure shows a majority of axSpA pts with &gt;2 IBPpar, but this is also seen in the no axSpA pts. IBPpar show high sensitivity but very low specificity with 'pain at night' as exception with a slightly better specificity. LR+ were, in both cohorts, much lower (figure) than the LR+ of 3.1 for IBP previously reported as diagnostic estimate in routine practice. <h3>Conclusion:</h3> IBP and the individual IBPpar. are commonly seen in patients with and without an axSpA diagnosis. Our data confirm results from Germany, showing that the diagnostic utility of IBP in a rheumatology setting is lower than previously assumed with a (very) low specificity and LR+. It seems the distinctive impact of IBP is expressed when physicians refer their patient to the rheumatologist. <h3>Reference</h3> [1] Poddubnyy D, et al. RMD Open2018;4:e000825 <h3>Disclosure of Interests:</h3> Manouk de Hooge: None declared, Floris A. van Gaalen: None declared, Marleen van de Sande Grant/research support from: Research support from Janssen, Novartis, Eli Lily, Consultant for: Received consultation fees from Abbvie and Novartis, Karen Fagerli: None declared, Lennart Jacobsson Consultant for: Eli-Lily, Janssen, Novartis, Pfizer, Speakers bureau: Abbvie., Dirk Elewaut: None declared, Désirée van der Heijde Consultant for: AbbVie, Amgen, Astellas, AstraZeneca, Bristol-Myers Squibb, Boehringer Ingelheim, Celgene, Daiichi, Eli-Lilly, Galapagos, Gilead, GlaxoSmithKline, Janssen, Merck, Novartis, Pfizer, Regeneron, Roche, Sanofi, Takeda, Union Chimique Belge, Filip van den Bosch Consultant for: AbbVie, BMS, Galapagos, Janssen, Lilly, Merck, Novartis, Pfizer and UCB, Speakers bureau: AbbVie, BMS, Janssen, Lilly, Merck, Novartis, Pfizer and UCB.