Background: The Crohn's and Ulcerative Colitis questionnaire (CUCQ) has previously been validated in patients with mild to moderate Crohn's and ulcerative colitis (UC). The aim of this study was to validate the tool in patients with acute severe UC.
Methods: We undertook a validation of the CUCQ in patients recruited to the COmparison of iNfliximab and ciclosporin in STeroid Resistant Ulcerative Colitis Trial (CONSTRUCT). We carried out psychometric analysis to examine the underlying dimensions of the scale, internal consistency and construct validity. We carried out stepwise regression to examine which items accounted for the greatest variance in the scale.
Results: We obtained complete data for 270 patients. The internal consistency of the CUCQ was excellent (Cronbach's alpha > 0.8). The CUCQ scores achieved significant correlations with two generic quality of life scales (SF-12 and EQ-5D), demonstrating good construct validity. Stepwise regression identified 16 items that accounted for greater than 95% of the variance of the CUCQ. Only three of the eight items selected for a short form in mild to moderate patients were selected for patients with acute severe UC.
Conclusions: The CUCQ demonstrated good validity in our sample of acute severe UC patients. Stepwise regression identified potential to shorten the tool, but that different items would be selected compared with less severe patients. If the tool is to be applied across the spectrum of disease it would be more appropriate to use the full 32 items in the scale. Further work to explore test-retest is required in acute patients.
Keywords: Inflammatory bowel disease; patient-reported outcome measures; quality of life; ulcerative colitis; validation.