An investigation of the correlations between subjective and objective measures of bowel inflammation in Spondyloarthritis

Introduction: Spondyloarthritis (SpA) and Inflammatory Bowel Disease (IBD) are related conditions of unknown aetiology demonstrating both common clinical features and common genetic and immunological pathomechanisms. Patients with SpA frequently exhibit intestinal inflammation and many develop significant gastrointestinal symptoms. Conversely, many patients with IBD develop an inflammatory arthritis. It has been proposed that an increase in intestinal permeability is an important mechanism in the aetiology of both conditions. However, to date the association between symptoms, intestinal pathology and altered gut permeability has been poorly elucidated. Methods: Patients who fulfilled the Assessments in Spondyloarthritis Internation Society (ASAS) criteria for axial spondyloarthritis were recruited to the study. Gastrointestinal symptoms were assessed using the Dudley Inflammatory bowel symptom Disease Questionnaire (DISQ). Intestinal permeability was measured using the three sugars test, which measures the differential urine recovery of ingested sucralose, L-rhamnose, and lactulose. Small-intestinal lesions were assessed with wireless capsule endoscopy (WCE). An indirect measure of intestinal inflammation (faecal calprotectin) was also used. Drug therapy – including the use and dose of NSAIDs was recorded. Patients with SpA were assessed clinically including a measure of disease activity - the Bath Ankylosing Spondylitis Disease Activity Index (BASDAI) and CRP. Results: In total, 35 patients and 15 healthy controls completed the DISQ and underwent a sucralose, lactulose and L-rhamnose absorption test to assess intestinal permeability. Ten patients underwent WCE. The majority of patients were taking NSAIDs (25/35). DISQ scores were significantly increased in patients compared to controls (p<0.0001) and were significantly correlated with BASDAI scores (p