Constipation is associated with incomplete bladder emptying in healthy children

Purpose To investigate the association between constipation and the results of uroflowmetry with post-void residual urine (PVR) tests in healthy children. Materials and Methods We enrolled healthy children aged between 4 and 12 years for evaluation of voiding and defecation function. A parent of children completed the questionnaire, and the children were asked to do uroflowmetry and PVR. Constipation is defined as defecation frequency ≤2 times/week or type 1–2 stool forms on Bristol stool scale. Uroflowmetry curve and PVR were eligible for analysis if voided volume was between 50 ml and expected capacity for age. Results Totally, 778 children (415 boys and 363 girls) with a mean age of 7.2 ± 2.2 years were eligible for analysis. The prevalence of constipation was 10.9% by low defecation frequency, and 28.4% by Bristol stool scale, respectively. Regarding the rate of constipation, there were no statistically significant differences between genders. Compared to children without low defecation frequency, constipated children had higher PVR (9.0 vs. 5.9 ml, P = 0.01), higher rate of PVR > 20 ml (17.7% vs. 7.1%, P = 0.01) and lower voiding efficiency (93.2% vs. 94.9%, P = 0.04). Compared to children without type 1–2 Bristol stool, constipated children did not have higher PVR (7.2 ml vs. 5.8 ml, P = 0.10), nor lower voiding efficiency (94.0% vs. 95.0%, P = 0.11). Urgency symptom score and rate of abnormal flow patterns were comparable between children with or without constipation. Conclusion Constipation defined as low defecation frequency was associated with incomplete bladder emptying in healthy children. Neurourol. Urodynam. 31:105–108, 2012. © 2011 Wiley Periodicals, Inc.