Development and preliminary validation of the questionnaire on pediatric gastrointestinal symptoms to assess functional gastrointestinal disorders in children and adolescents

Objective: The aim of this study was to develop a questionnaire assessing symptoms associated with pediatric functional gastrointestinal disorders (FGIDs) and to provide preliminary evidence for its validity and reliability in a tertiary care setting. Methods: The Questionnaire on Pediatric Gastrointestinal Symptoms (QPGS) was designed as both a parent report and child self-report measure based on the pediatric Rome II criteria for FGIDs. It was constructed in English, translated into French, and pilot tested in both languages. Initial validation was performed using the French version. Participants were 315 consecutive new patients aged 4 to 18, and their parents, presenting to a gastroenterology clinic and classified as having a functional problem. Content validity, item discrimination capacity, and reliability (parent-child concordance and temporal stability) were examined. Results: Analyses of parent and child reports indicated that all items were pertinent and variably distributed. Although children were reliable reporters, up to 42% of parents did not know about their children's gastrointestinal functioning. As many as 60% of parents of children 10 to 18 could not respond to questions about defecation and subjective symptoms. Concordance was generally fair to good, with Kappas and intraclass correlations of 0.40 to 0.70 on most items. Test-retest reliability was moderate to good for the majority of items. Conclusion: This study supports the content validity of the QPGS. Form A is a reliable measure for parents of children 4 to 9 years old, but the child self-report Form C appears to be more reliable for 10 to 18 year olds.