Introduction:
Breath tests are extremely popular in clinical practice to determine carbohydrate malabsorption. Assessment of symptoms to evaluate for carbohydrate intolerance are more relevant for clinical management. There is an unmet need for a validated,
test specific symptom questionnaire to evaluate carbohydrate-induced-perception.
Aim:
Development and validation of a symptom questionnaire for the assessment of carbohydrate
related perception.
Methods:
After literature search and initial focus group style interviews 5 relevant complaints
were identified and a VAS-based questionnaire was constructed. Criteria of validity
were determined during breath tests in 344 subjects. Correlation between the questionnaire
and a medical interview was determined.
Results:
The scale has good face validity as it is simple, easy to understand and brief. The content validity ratio according to Lawshe equales 1. Intraclass correlation coefficients for test-retest
reliability (n = 159; 30 minutes interval) demonstrate gut repeatability (p < 0.001),
Cohen's d as a measure of effect size is small (i.e. < 0.40; 0.19 or smaller for the
five symptoms). Principal component analysis obtained three factors: (A) intestinal
gas; (B) nausea; and (C) diarrhea. The significance according to Bartlett's test of
spherity is < 0.001. Convergent validity and discriminant validity is supported according to the multitrait-multimethod-matrix method. Moreover, the
results given by the questionnaire highly correlate with the result of the medical
interview (p < 0.001; Fisher exact test). Cronbach's alpha is 0.85, indicating good
internal consistency. Responsiveness to change has been verified during breath tests despite small effect
sizes (≤0.32).
Conclusion:
The adult CarboCeption Questionnaire (aCCQ) is a simple, test-specific questionnaire.
It is a valid instrument with excellent psychometric properties to assess gastrointestinal
symptoms after carbohydrate ingestion. The aCCQ should replace non-validated symptom
assessment during carbohydrate breath tests, e.g. by interview, use of non-validated
questionnaires or generic, non-test-specific instruments and to allow uniform diagnosis
of carbohydrate intolerance.
