Prevalence of undiagnosed axial spondyloarthritis in inflammatory bowel disease patients with chronic back pain: secondary care cross-sectional study.

OBJECTIVE: To elucidate the prevalence of undiagnosed rheumatology-verified diagnosis of axial spondyloarthritis (RVD-axSpA) in patients attending routine secondary care IBD clinics with chronic back pain. METHODS: Screening questionnaires were sent to consecutive patients attending IBD clinics in a university teaching hospital. Patients fulling the eligibility criteria (gastroenterologist-verified diagnosis, 18-80 years old, biologic therapy naive, no previous diagnosis of axSpA); and a moderate diagnostic probability of axSpA [self-reported chronic back pain (CBP) >3 months, onset <45 years] were invited for rheumatology assessment. This included medical review, physical examination, patient reported outcome measures, human leucocyte antigen B27, C-reactive protein, pelvic radiograph and axSpA protocol magnetic resonance imaging. A diagnosis of RVD-axSpA was made by a panel of rheumatologists. RESULTS: Of the 470 patients approached, 91 had self-reported CBP >3 months, onset <45 years, of whom 82 were eligible for clinical assessment. The prevalence of undiagnosed RVD-axSpA in patients attending IBD clinics in a secondary care setting, with self-reported CBP, onset <45 years is estimated at 5% (95% CI 1.3, 12.0) with a mean symptom duration of 12 (s.d. 12.4) years. CONCLUSION: There is a significant hidden disease burden of axSpA among IBD patients. Appropriate identification and referral from gastroenterology is needed to potentially shorten the delay to diagnosis and allow access to appropriate therapy.

The clinical utility of human leucocyte antigen B27 in axial spondyloarthritis.

The association between HLA-B27 and AS was first established in the early 1970s. Since then, our understanding of this disease has changed, such that we now recognize AS to be the extreme of the clinical phenotype within a disease spectrum known as axial SpA (axSpA). Recent advances in therapeutic options have driven the need for earlier diagnosis and many screening strategies have been proposed to facilitate this. In parallel, our understanding of axSpA genetics, and especially the contribution of HLA-B27, has expanded. In this article we will present and discuss the evidence supporting the use of HLA-B27 in clinical practice. We will briefly summarize the evolution of the concept of axSpA, the prevalence of HLA-B27 and axSpA and the potential role of HLA-B27 in the aetiopathogenesis of axSpA and focus on the utility of HLA-B27 in everyday clinical practice.