Comparing clinical profiles in spondyloarthritis with Crohn's disease or ulcerative colitis: insights from the ASAS-PerSpA study

Objectives Assuming SpA manifestations may vary among patients with different inflammatory bowel disease (IBD) subtypes, we explored the clinical characteristics associated with the presence of Crohn's disease (CD) or ulcerative colitis (UC) in patients with spondyloarthritis (SpA).Methods We included 3152 patients of ASAS-PerSpA study diagnosed with either axial SpA or peripheral SpA, according to their treating rheumatologist. Of these, 146 (4.6%) had confirmed IBD by endoscopy and were categorized into CD or UC groups. Demographics, clinical characteristics, treatments and patient-reported outcomes were compared between the two subgroups.Results From 146 patients included in the current analysis, 87 (59.6%) had CD [75 (86.2%) axial SpA and 12 (13.8%) peripheral SpA], and 39 (26.7%) had UC [34 (87.2%) axial SpA and 5 (12.8%) peripheral SpA]. CD and UC groups had similar age with average of 44.9 (13.5) vs 44.0 (13.0) years, respectively, and a slight male predominance in CD (63.2%) compared with UC (51.3%). Diagnostic delay for SpA was 7.0 (6.9) years for CD and 8.8 (8.1) years for UC. Chronic back pain was the most reported symptom present in 95.4% of CD patients and 89.7% of UC patients. Both groups had similar musculoskeletal phenotyping, with higher frequency of psoriasis (15.4%) and uveitis 28.2% in UC; and higher tendency to be HLA-B27 positive in CD (51.9% in CD vs.s 39.4% in UC).Conclusion In our analysis patients with SpA and concurrent CD or UC had mainly similar musculoskeletal phenotypes. However, they differ slightly in extra-musculoskeletal manifestations and HLA-B27 prevalence. What does this mean for patients?Spondyloarthritis (SpA) refers to a group of chronic inflammatory rheumatic diseases that share clinical and genetic features and develop primarily as arthritis of the spine and other joints. It often occurs at the same time as other inflammatory conditions such as Crohn's disease (CD) and ulcerative colitis (UC), which are types of inflammatory bowel disease (IBD). In our study, doctors and researchers looked at the health characteristics of more than 3000 patients with SpA included in the ASAS-PerSpA study, focusing on those who also had either CD or UC. We found that both groups of patients had similar symptoms, with small differences. For example, patients with CD were slightly more likely to test positive for HLA-B27, a genetic marker often associated with SpA, although this finding will require further research to better understand its meaning. The main take-home message from our study is that the type of IBD-whether CD or UC-does not really change the way that SpA affects a person. However, the distinction between CD and UC remains crucial in tailoring treatment strategies. This will ensure that patients diagnosed with SpA are receiving appropriate treatment, taking into account their specific type of IBD.