Identifying Axial Spondyloarthritis in Inflammatory Bowel Disease Patients Utilising Computed Tomography
The diagnosis of axial spondyloarthritis (axSpA) is hampered by diagnostic delay. Computed Tomography (CT) undertaken for non-musculoskeletal (MSK) indications in patients with inflammatory bowel disease (IBD) offers an opportunity to identify sacroiliitis for prompt rheumatology referral. The study aims to identify what proportion of IBD patients who underwent abdominopelvic CT for non-MSK indications have axSpA and explore the role of a standardised screening tool to prospectively identify axSpA on imaging.
Abdominopelvic CT scans of verified IBD patients, age range 18-55, performed for non-MSK indications were reviewed by radiology for presence of CT-defined sacroiliitis (CTSI, using criteria from a validated CT screening tool). All patients identified were sent a screening questionnaire and those with self-reported chronic back pain (CBP), duration > 3 months, onset < 45 years were invited for rheumatology review.
CTSI was identified in 60 of 301 patients. Thirty-two (53%) responded to the invitation to participate and 27 were enrolled. Of these, eight had a pre-existing axSpA diagnosis and five did not report CBP. Fourteen patients underwent rheumatology assessment; three of 14 (21.4% [95% CI: 4.7%, 50.8%]) had undiagnosed axSpA. In total, 11 of 27 (40.7% [95% CI: 22.4%, 61.2%]) patients had a rheumatologist verified diagnosis of axSpA.
At least 5.0% of IBD patients (3/60) undergoing abdominopelvic CT for non-MSK indications with CTSI have undiagnosed axSpA, and overall, 18.3% (11/60) have axSpA. This reveals a significant hidden population of axSpA and highlights the need for a streamlined pathway from sacroiliitis detection to rheumatology referral.
Prevalence of undiagnosed axial spondyloarthritis in inflammatory bowel disease patients with chronic back pain: secondary care cross-sectional study.
Chong Seng Edwin Lim, Mark Tremelling, Louise Hamilton, Matthew Kim, Alexander Macgregor, Tom Turmezei, Karl Gaffney, Prevalence of undiagnosed axial spondyloarthritis in inflammatory bowel disease patients with chronic back pain: secondary care cross-sectional study, Rheumatology, 2022;, keac473, https://doi.org/10.1093/rheumatology/keac473
To elucidate the prevalence of undiagnosed rheumatologist-verified diagnosis of axial spondyloarthritis (RVD-axSpA) in patients attending routine secondary care IBD clinics with chronic back pain.
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 naïve, 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.
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.
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.