Development and validation of the paediatric Carbohydrate Perception Questionnaire (pCPQ), an instrument for the assessment of carbohydrate‐induced gastrointestinal symptoms in the paediatric population

BACKGROUND: There is an unmet need for a validated, test‐specific symptom questionnaire to evaluate carbohydrate perception during breath tests. Our aim was to develop and validate a questionnaire for the assessment of symptoms after a provocative carbohydrate load. METHODS: After a literature search and initial focus group‐style interviews, five relevant complaints were identified. Responses were given on a Likert‐type faces scale with a language children use and understand. Reliability, validity and responsiveness to change were established by the implementation of the questionnaire during breath tests in 215 pediatric subjects. Correlation between the questionnaire and a medical interview by a pediatrician who was blinded to the results of the questionnaire (n = 19) was determined. KEY RESULTS: The questionnaire had good face and content validity (Lawshe ratio = 1). Intraclass correlation coefficients for test‐retest reliability (n = 116) demonstrated good repeatability (P < .001), and effect sizes were small (Cohen's d < 0.15 for all symptoms). Convergent validity and discriminant validity were supported according to the multitrait‐multimethod matrix method. The results obtained by the questionnaire correlated highly with the result of the medical interview (P < .001; Fisher's exact test). Cronbach's alpha was 0.81. Responsiveness was verified for the whole patient group and subgroups with medium to high effect sizes. CONCLUSIONS AND INFERENCES: The paediatric Carbohydrate Perception Questionnaire (pCPQ) is a simple, test‐specific questionnaire for a pediatric population. It is a valid instrument with excellent psychometric properties to assess gastrointestinal symptoms after carbohydrate ingestion. The pCPQ can replace non‐validated symptom assessment during carbohydrate breath tests and allows a standardized diagnosis of carbohydrate intolerance.