The SpACE Study - Small Bowel Crohn's Disease and Spondyloarthropathies

Overview

Inflammatory bowel disease is clinically associated with spondylarthropathies in 5-15% of cases. Protocol colonoscopic assessment demonstrated asymptomatic inflammation characteristic of Crohn's disease in up to 1/3 of SpA patients. Videocapsule endoscopy is a superior diagnostic tool to detect small bowel mucosal pathology. However, it has been infrequently used to evaluate bowel inflammation in spondylarthropathies. This study compared the accuracy of videocapsule endoscopy to standard ileocolonoscopy for the detection of inflammatory bowel lesions in patients with spondylarthropathies, and to describe the clinical and laboratory predictors of small bowel inflammation in this cohort.

The link between chronic inflammatory bowel disease and arthritis is well established. IBD is associated with 3 patterns of arthritis (1), one of which is spondylarthropathy (2). spondylarthropathies is not uncommon, with 3-6% of patients with IBD affected, while radiologic sacroileitis is evident in up to 18% of patients. SpA associated with IBD differs from that of idiopathic ankylosing spondylitis in that the prevalence of HLA-B27, although high (20-40%), is significantly lower than in typical AS, where its prevalence is characteristically 90%. Both inflammatory bowel disease and spondylarthropathies show familial clustering and may coexist. Idiopathic ankolysing spondylitis and ankolysing spondylitis usually occurs without overt signs of intestinal inflammation. However, ileocolonoscopy studies have shown a high prevalence (30-44%) of asymptomatic inflammation of the terminal ileum. The nature of this inflammation is highly characteristic of Crohn's disease. Among spondyloarthropathies patients with subclinical inflammation, only 6% were reported to eventually develop clinically apparent inflammatory bowel disease. A more recent review of endoscopy-based studies detected Crohn's disease more frequently, in 18-48 % of patients with spondyloarthropathies and in 5-11% of ankolysing spondylitis.. However, conventional endoscopic and radiological techniques are limited in their capacity to investigate the entire small bowel, and could easily miss significant mucosal lesions due to Crohn's disease. Capsule endoscopy has been shown to be superior to conventional diagnostic techniques for the investigation of suspected Crohn's disease. The primary objective of this study is to demonstrate that this safe, non-invasive technique will reveal unidentified small bowel lesions in asymptomatic subjects with spondylarthropathies or ankolysing spondylitis more reliably than ileo-colonoscopy with biopsies. Clinical implications: Spondylarthropathies, ankolysing spondylitis and inflammatory bowel disease are clinically, genetically and pathologically linked. Anti-tumor necrosis factor agents, including Adalimumab, Etanercept and Infliximab, are all efficacious and cost-effective in treating spondylarthropathies and ankolysing spondylitis. Since only some anti-TNF molecules are highly effective for both Crohn's disease and spondylarthropathies and related arthropathies, the present study ideally would lead to a change in general therapeutic practice, leading to wider use of molecules with a wide scope of therapeutic success.