Comparison of colonic transit time between patients with constipation-predominant irritable bowel syndrome and functional constipation.

BACKGROUND/AIM Functional constipation (FC) and constipation-predominant IBS (C-IBS) are two main subtypes of constipation. Using radio-opaque markers is an easy and cost effective method to measure colonic transit time (CTT). We designed this study to compare the CTT between these two groups of constipated patients. METHODS Patients with chronic constipation of no organic etiology were classified as having FC or C-IBS according to the Rome II criteria. All patients ingested 10 radio opaque markers daily for six days. A plain abdominal X-ray was taken on the seventh day. To calculate the total and segmental colonic transit time in hours, number of markers in right and left colonic and rectosigmoid area were counted and multiplied by 2.4. The mean total and segmental colonic transit time were compared between the two groups. RESULTS A total of 100 patients (50 FC and 50 C-IBS) were enrolled. The mean (SD) total CTT was not significantly different between FC patients (52.2 [35.5] h) and C-IBS patients (41.2 [31.6] h; p = 0.10). The mean rectosigmoid transit time was significantly slower in FC patients (19.9 [15.5] h) compared to C-IBS patients (11.9 [10.6] h; p = 0.003). CONCLUSION Rectosigmoid transit time in FC patients is slower than in C-IBS patients.