Validation of the Dudley inflammatory bowel symptom questionnaire for the assessment of bowel symptoms in axial SpA: Prevalence of clinically relevant bowel symptoms and association with disease activity

Objectives: To validate the Dudley Inflammatory Bowel Disease Questionnaire (DISQ) for determining the presence and severity of bowel symptoms in axial SpA. Methods: Seventy-seven SpA patients were assessed for disease activity using the BASDAI. All participants, including 32 healthy controls and 29 patients with Crohn's Disease (CD), completed the DISQ and an assessment of stool form and frequency. Validation of the DISQ was undertaken in accordance with OMERACT criteria. Results: Validity of the DISQ for measuring bowel symptoms in SpA was confirmed (Cronbach's α 0.79). Mean DISQ scores (s.d.) were: controls 2.6 (2.6), SpA 8.7 (6.1) and CD 17.1 (10.2). Differences were significant between controls and SpA, and SpA and CD, and correlated with disease activity (ρ 0.27, P = 0.02). In SpA, DISQ scores of those taking NSAIDs (n = 59) did not differ from those not taking NSAIDs (n = 18) (P = 0.31). Stool form and frequency differed significantly between SpA patients and healthy controls (P < 0.001). Using the DISQ the prevalence of clinically relevant bowel symptoms in SpA is 31%, and 7.8% experience bowel symptoms equivalent to active CD. Conclusion: The DISQ is a valid measure of bowel symptoms in SpA. Bowel symptoms are prevalent in SpA and correlate with disease activity. Symptoms do not relate to treatment with NSAIDs. We conclude that bowel symptoms should be included as a domain in the clinical assessment of patients with SpA and that the DISQ has potential as an outcome measure in clinical trials.