The following is a summary of “Identifying Axial Spondyloarthritis in Patients With Inflammatory Bowel Disease Using Computed Tomography,” published in the July 2023 issue of Rheumatology by Lim et al.

Diagnostic delay hinders the axial spondyloarthritis (axSpA) diagnosis. Patients with inflammatory bowel disease (IBD) who undergo computed tomography (CT) for nonmusculoskeletal (non-MSK) indications have an opportunity to identify sacroiliitis for prompt rheumatology referral. This study seeks to determine what proportion of patients with inflammatory bowel disease (IBD) who underwent abdominopelvic CT for non-MSK indications have axSpA and to investigate the function of a standardized screening tool to identify axSpA on imaging prospectively. 

Abdominopelvic CT scans of patients with confirmed IBD, aged 18 to 55 years, administered for non-MSK indications were reviewed by radiologists for the presence of CT-defined sacroiliitis (CTSI) using CT screening tool criteria. All identified patients received a screening questionnaire, and those with self-reported chronic back pain (CBP), CBP duration of more than 3 months, and onset age of fewer than 45 years were invited for rheumatology review. CTSI was identified in 60 of 301 patients (19.9%). About 32 (53%) of these 60 patients responded to the invitation to participate, and 27 (84.3%) of those 32 patients were enrolled. Eight had a preexisting diagnosis of axSpA, while five did not report CBP. Three out of fourteen (21.4%, 95% CI: 4.7-50.8) patients evaluated for rheumatology did not have axSpA. 

A rheumatologist diagnosed 11 out of 27 patients (40.7%, 95% CI 22.4-61.2) with axSpA. In this study, 5% (3/60) of IBD patients undergoing abdominopelvic CT for non-MSK indications were found to have undiagnosed axSpA, and 18.3% (11/60) were discovered to have axSpA. This underscores the need for a streamlined pathway from sacroiliitis detection to referral to rheumatology by revealing the existence of a substantial population of axSpA patients who have been previously undiagnosed.

Source: jrheum.org/content/50/7/895