PO:03:039 | Extraintestinal manifestations of enteropathic arthritis vary in relation to inflammatory bowel disease behaviour, localization, and extent

Bernardo D'Onofrio¹, Nicoletta Luciano^2|3, Simone Parisi¹, Maria Chiara Ditto¹, Cristina Bezzio^2|4, Enrico Fusaro¹, Alessandro Armuzzi^2|4, Carlo Selmi^2|3 | ¹Division of Rheumatology, AOU Città della Salute e della Scienza, Torino, Italy; ²Department of Biomedical Sciences, Humanitas University, Pieve Emanuele, Italy; ³Rheumatology and Clinical Immunology, IRCCS Humanitas Research Hospital, Rozzano, Italy; ⁴Inflammatory Bowel Disease Unit, IRCCS Humanitas Research Hospital, Rozzano, Italy

Background. Spondyloarthritis (SpA) and inflammatory bowel diseases (IBD), such as Crohn’s disease (CD) and ulcerative colitis (UC) coexist in enteropathic arthritis (IBD-SpA), which is the less studied phenotype within the SpA spectrum. IBD display well-defined characteristics with regard to disease phenotype, localization, and extent. Conversely, no data explore the possible musculoskeletal and extra-musculoskeletal differences of IBD-SpA according to IBD features. The aims of the study were (1) to assess the demographic, clinical, and treatment differences between CD-SpA and UC-SpA, (2) to evaluate whether SpA manifestations vary according to IBD characteristics.

Methods. Data were retrieved from a multicentric cohort of SpA-IBD patients (HSpAc and TSpAc). Demographic and clinical data were collected at baseline and at the last available follow-up visit. IBD patterns (CD, UC), and localization, extent, and behaviour of the disease were evaluated according to the Montreal classification criteria. CD was as inflammatory (B1), stenosing (B2), fistulizing (B3), with a possible perianal involvement, with regard the behaviour, and as ileal (L1), colonic (L2), ileo-colic (L3), with/without upper gastro-intestinal (L4) with regard the localization. Similarly, the extent of UC can be limited to the rectum (E1) or be spread to the left (E2) or the whole colon (E3). Extraintestinal manifestations included peripheral and axial arthritis, enthesitis, dactylitis, uveitis, psoriasis, and erythema nodosum.

Results. We analysed 87 patients with IBD-SpA (66 from the HSpAc, 21 from the TSpAc), the largest part (n=54) with CD and the remaining (n=33) with UC; no differences were observed between the two subgroups. Among CD cases, dactylitis was more common in patients with fistulizing disease both at univariate analysis [2 (40%) for B3 vs. 2 (7%) for B1 and 0 for B2; p=0.010] and at binary logistic regression [OR (95% CI) of 19 (1.2-292.3); p=0.035], and with an upper gastro-intestinal tract involvement [2 (100%) for L4+ vs. 2 (4%) L4-; p<0.001]. According to disease localization, peripheral arthritis was significantly less detected in those with ileo-colic disease compared to the other subtypes, both at univariate analysis [13 (62%) for L3 vs. 27 (93%) for L1 and 4 (100%) for L2; p=0.012] and at binary logistic regression [OR (95% CI) of 0.12 (0.02-0.65); p=0.013]. Erythema nodosum was more common in CD-SpA patients with a ileo-colic involvement, but only at univariate analysis [5 (24%) for L3 vs. 0 for L1 and L2; p=0.013]. Comparing CD patients with and without perianal involvement we observed a more common association with uveitis within the former [3 (37%) for perianal disease vs. 3 (6%) for non-perianal disease; p=0.010]), apparently not driven by the HLA-B27 allele (p=ns).

Conclusions. Extraintestinal manifestations of IBD-SpA might vary according to IBD phenotypes. Profiling patients according to IBD characteristics might be useful in designing studies and tailored trials for IBD-SpA.