EULAR 2016 | Daily Highlights
DOES THE PRESENCE OF MULTIPLE SPA-FEATURES IN PATIENTS WITH CHRONIC BACK PAIN ALWAYS LEAD TO DIAGNOSIS OF AXIAL SPONDYLOARTHRITIS?Abstract: OP0085
Authors: Z. Ez-Zaitouni1,*, P. Bakker1, M. van Lunteren1, M. Reijnierse2, I. J. Berg3, R. Landewé4, M. van Oosterhout5, M. Lorenzin6, D. van der Heijde1, F. van Gaalen1
Co Authors: 1Rheumatology, 2Radiology, LUMC, Leiden, Netherlands, 3Rheumatology, Diakonhjemmet Hospital, Oslo, Norway, 4Rheumatology, AMC, Amsterdam, 5Rheumatology, GHZ, Gouda, Netherlands, 6Rheumatology, University of Padova , Padova, Italy
The number of clinical SpA-features plays an important role in the Assessment of SpondyloArthritis international Society (ASAS) modified Berlin algorithm for the diagnostic work-up of patients (pts) with a suspicion of axial SpA (axSpA).
To investigate whether all pts with short duration chronic back pain (CBP) and multiple SpA-features are always diagnosed as axSpA by the rheumatologist and to describe the features of these patients.
The SPondyloArthritis Caught Early (SPACE)-cohort includes CBP pts ( ? 3 months, ? 2 years, onset < 45 years) from various European rheumatology centres. Baseline data were used for the analyses. Following a fixed protocol all pts underwent a full diagnostic work-up consisting of performance of MRI and radiographs of sacroiliac joints (MRI-SI and X-SI), acute phase reactants, HLA-B27 testing, and assessment of other SpA-features (inflammatory back pain (IBP), good response to NSAIDs, family history for SpA, peripheral arthritis, dactylitis, enthesitis, uveitis, inflammatory bowel disease (IBD), and psoriasis). Local radiologists or rheumatologists from the different centres interpreted MRI-SI and X-SI on presence of sacroiliitis (yes/no) using global assessment as part of routine clinical practice. Total number of SpA-features was calculated excluding sacroiliac imaging and HLA-B27 status. The treating rheumatologist provided clinical diagnosis of pts and the ASAS-criteria for axSpA were used for classification.
A total of 522 pts were analysed in this study: before sacroiliac imaging and HLA-B27 testing 164/522 (31.4%) pts had no or 1 SpA-feature, 148/522 (28.4%) pts had 2 SpA-features, 85/522 (16.3%) pts had 3 SpA-features, and 125/522 (23.9%) pts had ?4 SpA-features respectively. IBP, good response to NSAIDs, and positive family history for SpA were most common in all subgroups (0 or 1 feature: 26.8%, 8.5%, and 16.5% of pts; 2 features: 72.3%, 34.5%, 39.9%; 3 features: 87.1%, 60.0%, 54.1%; ?4 features: 94.4%, 83.2%, 68.0% respectively). Of the pts with 2 and 3 SpA-features with negative X-SI 20/132 (15.2%) and 9/78 (11.5%) did not have axSpA diagnosis despite being HLA-B27+ (Figure 1). All pts with ?4 SpA-features and X-SI+ (n=28) were diagnosed with axSpA. In contrast to what would be expected by following the modified Berlin algorithm for pts with ?4 SpA-features, 18/94 pts (19.1%) with negative imaging (of which 4 HLA-B27+), were not diagnosed with axSpA by their rheumatologist. Multivariate regression analysis of presence of SpA-features identified MRI-SI+ (OR 41.7;95%CI 17.3.1-100.5), X-SI+ (OR 31.5;95%CI 3.1-321.0), HLA-B27+ (OR 4.7;95%CI 2.5-8.6), uveitis (OR 4.3;95%CI 1.5-12.7), IBP (OR 2.5;95%CI 1.4-4.7), heel enthesitis (OR 5.5;95%CI 2.7-11.4), IBD (OR 3.2;95%CI 1.2-8.8), elevated CRP/ESR (OR 2.7;95%CI 1.4-5.3), and psoriasis (OR 2.5;95%CI 1.0-6.0) as significant independent predictors of axSpA diagnosis.
In this cohort of pts with CBP having numerous SpA-features did not automatically lead to a clinical axSpA diagnosis but positive imaging was the main driving factor to diagnosis of axSpA.
Disclosure of Interest
None declared DOI: 10.1136/annrheumdis-2016-eular.2707
The FDA had issued important concerns with regard to the potential misuse of the ASAS classification criteria for diagnosis of axial spondyloarthritis (axSpA) and consequent potential overdiagnosis by simply checking boxes. As a consequence, TNF inhibitors have not been licensed for the treatment of non-radiographic axSpA in the US. Regarding diagnosis of axSpA, an algorithm had been published more than 10 years ago and slightly modified by the ASAS recently (the so-called Berlin algorhythm): a patient with chronic back pain can be diagnosed as having axSpA in the absence of definite radiographic changes of the sacroiliacal joints even if HLA-B27 status is unknown and MRI not performed, in the presence of at least 4 typical axSpA features. If only 2-3 SpA features are present, a diagnosis of axSpA can be made if HLA-B27 is positive. MRI results would be needed in the presence of only 1 SpA feature in addition to HLA-B27 positivity. The present study alludes to both issues and demonstrates that rheumatologists in real life do rely more heavily on results of MRI for making a diagnosis of axSpA. Nearly 20% patients with at least 4 SpA features were not diagnosed with axSpA if the MRI was negative. Does this mean that the Berlin algorithm is not valid any longer? No, certainly not. First, from the beginning, the algorhythm was only meant to be used as a rough guidance. It indicates that the more axSpA features are present, the most likely a diagnosis can be made. Second, looking at the discrepancies found in clinical trials between local and central reading of MRIs, giving to much weight to MRI findings might seem adventurous. In a preliminary analysis of patients with nonradiographic axSpA in the SCQM cohort we have found a much better response to TNF inhibitors in patients fulfilling the HLA-B27-only arm than the MRI-only arm of the ASAS classification. More data is definitely needed to establish whether more weight should be given to individual axSpA features in the ASAS classification.
PD Dr. Adrian Ciurea
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