Introduction and hypothesis: A study was conducted to validate a constipation questionnaire based on the Rome III criteria.
Methods: Women attending outpatient clinics completed a constipation questionnaire based on the Rome III Criteria. The internal reliability, the test-retest as well as the content and construct validity of the questionnaire were evaluated.
Results: Two hundred one women were studied. Of the women, 28% (56/201) reported constipation but only 14% of these (8/56) could be defined as constipated accordingly to the Rome III Criteria. Nine percent of women (13/145) who did not report constipation were classified as constipated accordingly to the Rome III Criteria. The questionnaire had good reliability (Cronbach's alpha of 0.85 and ICC of 0.85). However, the questionnaire did not have significant construct validity with patients' self-report of constipation, stool frequency and stool form (Pearson chi-square P > 0.05).
Conclusions: The Rome III Criteria questionnaire is a reliable and reproducible tool but does not appear to be a valid instrument in diagnosing constipation.