Gut linked to both inflammatory bowel disease and axial spondyloarthritis with high cross-risk ratio

There is a clear link between gut inflammation, axial spondyloarthritis (SpA) and the development of inflammatory bowel disease (IBD), the ISR 2018 Autumn Meeting heard.

Prof Dirk Elewaut, Professor of Rheumatology and Immunology, Ghent University, Belgium, discussed the link between the gut in SpA versus the joint in IBD. Prof Elewaut posited that gut inflammation is a driver of joint inflammation in SpA. His research team has found that about 50 per cent of patients presenting to rheumatologists with a clinical presentation of SpA have microscopic gut inflammation, regardless of subtype, and unrelated to clinical gastrointestinal symptoms.

Subclinical gut inflammation is associated with long-term outcomes of joint symptoms, more extensive disease and, conversely, remission of gut inflammation is associated with disappearance of joint symptoms, he maintained.

Persistence of gut inflammation has been specifically linked to the evolution of Crohn’s disease and ankylosing spondylitis (AS) and is also associated with an accelerated need for biologic therapy, the professor stated.

He also quoted Icelandic genealogy data highlighting the common genetic background for IBD and AS, with a three-fold elevated cross-risk radio of developing IBD if a first-degree relative has AS, and vice versa.

The findings suggest that one or more undiscovered genetic variants may underlie the risk of both diseases.

Meanwhile, a separate meta-analysis suggested that up to 20 per cent of IBD patients can have axial spondyloarthritis, though he cautioned that it was based primarily on imaging and was uncertain if it would be replicated if it was analysed in a prospective manner by rheumatological experts. “So it is common, but I think a little bit less common than this study suggests.” Prof Elewaut added that detection can be hampered by the fact that when IBD patients are placed on steroids and immunosuppressants, they can mask/alleviate any relevant joint symptoms so clinicians need to investigate such symptoms during the diagnosis period.

Concluding, Prof Elewaut said further refinement and validation of biomarkers (including multiparameter sets) are needed for the optimal management of arthritic diseases.

Speaking to the Medical Independent, Prof Elewaut said it is important that clinicians are aware of the presence of gut inflammation and how it can determine severity of disease. “In patients with IBD and SpA manifestations, there are common pathways but also different pathways, so you can have a disconnect between what is happening in the gut and what is happening in the spine or peripheral joints, so that is something to be aware of when treating a patient with SpA or IBD.”