Validation and clinical utility of a bowel habit questionnaire in school-age children

Abstract

Objectives: The aim of the study was to validate a brief Bowel Habit Questionnaire (BHQ) with prospectively obtained data from a 14-day diary and to determine whether the BHQ predicts the development of medically significant constipation (MSC) during the following year.

Materials and methods: The BHQ was distributed to parents of children ages 5 to 8 years during health supervision visits. Both the BHQ and subsequent diary were scored to indicate constipation if at least 2 of the following were reported: infrequent bowel movements, stool accidents, straining, avoidance, discomfort with defecation, or passing large stools >25% of the time. One year later, the BHQ was repeated to assess for MSC, defined as medical encounters about constipation or use of enemas, suppositories, laxatives, or stool softeners.

Results: MSC was reported for 57 (13.7%) of 416 children on the first BHQ. Paired BHQ and diary data were obtained for 269 children; 54 (20.1%) had diary scores indicating constipation. BHQ had a sensitivity of 59.6% (95% confidence interval [CI] 46.7%-71.4%) and a specificity of 82.6% (95% CI 77.0%-87.1%). One year later, 11 children (5.2%) had developed new-onset MSC; 7 (63.6%) of these children had initial BHQ scores of at least 2. Positive and negative predictive values for MSC were 19.4% (95% CI 9.8%-35.0%) and 97.7% (94.2%-99.1%), respectively.

Conclusions: Parents often do not recognize constipation in young school-age children and most constipated children remain untreated. A brief screening questionnaire in this population proved to be valid but only moderately sensitive; efforts to improve sensitivity are needed before recommending it for routine use.

Trial registration: ClinicalTrials.gov NCT00398021.