Ulcerative Colitis-Symptom Questionnaire: Valid for Use in Adults with Moderately to Severely Active Ulcerative Colitis.

BACKGROUND: Due to wide-ranging impacts of Ulcerative Colitis (UC), regulatory authorities emphasize the importance of including validated patient-reported symptom severity measures in clinical trials. AIM: To describe the development and validation of the Ulcerative Colitis-Symptom Questionnaire (UC-SQ). METHODS: The UC-SQ was developed in a qualitative study involving a targeted literature review, semi-structured concept elicitation interviews, and combined concept elicitation/cognitive interviews. Measurement properties, including item-level analyses, factor structure, reliability, validity, responsiveness, and clinically meaningful change were evaluated using data from a phase 2b, randomized trial in adults with UC (N = 113). RESULTS: Fourteen symptom concepts were elicited across 22 interviews, with saturation at the fifth interview. Twenty-two items were unmodified as cognitive interview participants interpreted underlying concepts correctly. Instructions were clear and items were relevant, with appropriate response options and recall periods. Reduction to 17 items was completed prior to psychometric testing. Two items (joint pain/constipation) did not contribute to reliability in initial testing and were included as non-scored items. The 15-item UC-SQ showed evidence of internal consistency (α = 0.86) and test-retest reliability (intraclass correlation coefficient = 0.88). The UC-SQ discriminated by disease severity as defined by Mayo and Inflammatory Bowel Disease Questionnaire scores (p < 0.0001). Convergent validity was supported by strong correlations with criterion measures. The UC-SQ was responsive in patients indicating change in other measures. A 10-point decrease from baseline indicated within-patient meaningful improvement. CONCLUSIONS: The UC-SQ is reliable, valid and responsive, with a 10-point improvement estimating within-patient clinically meaningful improvement. The tool is fit-for-purpose as a key endpoint in pivotal UC trials.