Background/Purpose: Axial spondyloarthritis (axSpA) is closely related to inflammatory bowel disease (IBD), however contemporary data on the burden of hidden disease in the IBD population is lacking. This is despite significant advances in imaging and improved understanding of the axSpA disease spectrum. Recognition of the association between axSpA and IBD is important in order to bridge the gap of diagnostic delay and streamline referral for treatment. This study aims to elucidate the hidden prevalence of axSpA in IBD patients in secondary care.

Methods: Screening questionnaires were sent to consecutive IBD patients attending routine clinics (September 2017 to February 2019) in a large teaching hospital serving an estimated 3000 IBD patients. Patients fulling the eligibility criteria (gastroenterologist-verified diagnosis, 18 to 80 years old, biologic therapy naïve, no previous diagnosis of axSpA); and a moderate-diagnostic-probability of axSpA (self-reported chronic-back-pain (CBP) onset before 45 years old) were invited for rheumatological assessment. This included a medical interview, physical examination (including joint and tender point count, MASES, dactylitis count, BASMI), patient reported outcomes (BASDAI, BASFI, BASGI, Harvey-Bradshaw-Index, Partial-Mayo-Index), relevant laboratory tests (CRP, ESR, HLA-B27), pelvic radiograph, axSpA protocol MRI, and remote review by a panel of expert axSpA rheumatologists.

Results: The prevalence of rheumatologist-verified diagnosis of axSpA was 5% (95% CI 1.3,12.0) with a mean delay to diagnosis of 12 (S.D. 12.4) years. Using contemporary classification criteria, the prevalence of axSpA was 39% (ESSG), 12% (ASAS), (mNYC) respectively. Of the 470 patients approached, 41% (n=191) responded. Of the 173 valid completed questionnaires, 53% (n=91) had CBP onset < 45 yr and 90% (n=82) attended for clinical assessment. The mean age was 52 yr, 37% male. 74% ulcerative colitis, 26% crohn’s disease, 66% disease remission. The prevalence of physician verified inflammatory back pain (IBP) was 20%. However, 38%, 35%% and 29% fulfilled Calin, Berlin and ASAS classification criteria respectively. Previous history of acute anterior uveitis (AAU), skin psoriasis, other peripheral musculoskeletal (MSK) axSpA manifestations were reported by 5%, 7% and 16% respectively. Thirty-five percent (n=29) had a positive family history of axSpA-related conditions (62% IBD, 52% skin psoriasis, 4% axSpA). Mean CRP and ESR were 4.3mg/L and 14mm/h respectively; 7% HLA-B27 positive; 4% ASAS positive MRI (active sacroiliitis); 6% fulfilled mNYC radiological criteria.

Conclusion: The hidden prevalence of rheumatologist-verified diagnosed axSpA in IBD patients seen routinely in a hospital setting with self-reported CBP which started before 45 years old is conservatively estimated at 5%. This represents a significant hidden disease burden. Greater awareness and education are still needed.  We need to get it right first time by appropriate identification and referral from gastroenterology to rheumatology, in order to potentially shorten the delay to diagnosis and allow access to effective therapy.

« Back to ACR Convergence 2020

ACR Meeting Abstracts - https://acrabstracts.org/abstract/prevalence-of-undiagnosed-axial-spondyloarthritis-among-patients-with-inflammatory-bowel-disease-a-secondary-care-cross-sectional-study/