Predictive value of colonic transit time indices for differentiating nonnormal from normal sensation in children with chronic functional constipation identified by anorectal manometry

BACKGROUND: Constipation is a common disorder in pediatrics, although the underlying pathogenesis is not fully understood. The current study aimed at evaluating the efficacy of different colonic transit time (CTT) indices for differentiating normal from nonnormal sensation in children with chronic functional constipation identified by anorectal manometry (ARM). MATERIALS AND METHODS: In this cross-sectional study, 47 children with chronic idiopathic constipation, aged 5–15 years, were studied. The total and segmental CTTs were estimated by administering multiple radiopaque markers for 6 days and performing a single abdominal radiograph on day 7. Anorectal function was evaluated using manometry with an Arhan probe. The predictive value of CTT indices was evaluated by receiver operating characteristic curve analysis. Area under the curve (AUC) along with 95% confidence interval (CI) as well as sensitivity and specificity was calculated. RESULTS: The mean age of the participants was 8.30 ± 2.99 years, with a mean constipation duration of 2.90 ± 0.46; 28 children were identified with nonnormal sensation. The mean values of CTT indices were statistically significantly longer in the nonnormal sensation patients than that in the normal group (P < 0.001). In addition, the mean values of manometry parameters were statistically significantly higher in nonnormal sensation patients than that in normal group (P < 0.01). Among CTT indices, rectosigmoid CTT (AUC [95% CI] =0.999 [0.99–1]; P < 0.001) with sensitivity = 100% and specificity = 94.7% and total CTT (AUC [95% CI] =0.972 [0.93–1] P < 0.001) with sensitivity = 82.3% and specificity = 100% had the highest predictive values for differentiating nonnormal from normal sensation patients. CONCLUSION: CTT is a simple and noninvasive technique for classifying patients with constipation. It can be used for identifying children suffering from chronic constipation with nonnormal sensation reliably, instead of ARM. Colonic inertia may be a manifestation of global motility dysfunction. Children with delayed distal colonic transits are more likely to have abnormal defecation dynamics.