Development and Validation of the TUMMY-UC: A Patient-Reported Outcome for Pediatric Ulcerative Colitis

Abstract

The TUMMY-UC is a patient-reported outcome measure for pediatric ulcerative colitis (UC) with an observer-reported outcome version for children aged <8 years. It includes eight items selected by concept elicitation interviews. We aimed to finalize the TUMMY-UC by cognitive interviews (stage 2) and to evaluate the index for its psychometric properties (stage 3). The TUMMY-UC items were first finalized during 129 cognitive debriefing interviews. Then, in a prospective, multicenter validation study, 84 children who underwent colonoscopy or provided stool for calprotectin completed the TUMMY-UC and various measures of disease activity. Assessments were repeated after 7 and 21 days for evaluating reliability and responsiveness. During stage 2, the items were formatted with identical structure to ensure conceptual equivalence and weighted based on ranking of importance. In stage 3, the TUMMY-UC total score had excellent reliability in repeated assessments (intraclass correlation coefficient, 0.90; 95% confidence interval, 0.84-0.94). It also had moderate to strong correlations with all constructs of disease activity: r= 0.70 with UC endoscopic index of severity, r= 0.63 with the IMPACT-III questionnaire, r= 0.43 with calprotectin, r= 0.80 with the Pediatric Ulcerative Colitis Activity Index, r= 0.75 with global assessment of disease activity, and r= 0.46 with C-reactive protein (all P < .015). The index had excellent discrimination of disease activity, with a score of <9 defining remission (area under the receiver operating characteristic curve, 0.95; 95% confidence interval, 0.93-0.99). The ΔTUMMY-UC showed high responsiveness and differentiated well between children who experienced changed from those with no change. The TUMMY-UC, constructed from patient-reported outcome and observer-reported outcome versions, is a reliable, valid and responsive index that can be now used in practice and clinical trials.