Reliability and Validity of Korean Bowel Disease Questionnaire for Functional Gastrointestinal Disorders

Objectives: The Korean version of Bowel disease questionnaire (BDQ-K) was developed to evaluate the symptom items required to meet the definition of functional gastrointestinal disorders (FGIDs). We evaluated the test-retest reliability and validity of the self-reported BDQ-K and prevalence of functional dyspepsia (FD) and irritable bowel syndrome (IBS) according to the Rome-III criteria. Methods: Sixty-nine patients participated in the test-retest reliability study, with a two week interval, and another 74 patients were enrolled to assess the self-reported questionnaire versus a doctor's interview (concurrent validity). A total of 3,325 subjects (mean age, 44 +/- 9 yrs; 58.3% male) presenting for an upper endoscopy responded to the BDQ-K at a health promotion center, but 797 subjects with organic diseases were excluded. Results: In the validity study of the BDQ-K, the median kappa value was 0.74 (0.36 similar to 1.0). The median kappa value for the test-retest was 0.56 (range 0.22 similar to 1.0), including abdominal pain (kappa=0.51, P<0.001), pain onset before 6 months (kappa=0.51, P<0.001), epigastric pain (kappa=0.69, P<0.001), early satiety (kappa=0.40, P<0.001), and postprandial fullness (kappa=0.34, P<0.001). The prevalence of FD was 8.3% (209/2,528); epigastric pain more than once a week 4.4%, early satiety 2.5%, and postprandial fullness 6.1%. FD was more prevalent in women (P=0.001). The prevalence of IBS was 6.1% and IBS also predominated in women (7.1% vs 5.1% in men, P=0.032). Conclusion: The BDQ-K is a reliable and valid instrument for identifying FGIDs. The prevalence of FD according to the Rome III criteria was 8.3% and that of IBS was 6.1%.