Functional Constipation And Bladder Capacity And Severity Of Enuresis In Children: A Correlation Study

Background: Primary nocturnal enuresis (PNE) is the most common voiding problem among pediatric patients. Enuresis has a complex etiology involving bladder function derangements, circadian rhythm, genetics, psychological factors, and the central nervous system. In this study, we studied the correlations among constipation, bladder capacity, and severity of PNE in children. Methods: The study was conducted in children and adolescents aged 5-15 years and diagnosed with PNE in Beijing Children's Hospital, Capital Medical University. Severity of nocturnal enuresis was classified as mild-moderate and severe according to the frequency of enuresis. In particular, more than six wet nights weekly was classified as severe and six or less as mild-moderate. Rome III questionnaire was used to determine whether a patient has constipation. Urinalysis and urinary ultrasound were performed for all participants. A logistic regression model was used to investigate the relationship between the severity of enuresis and possible predictive variables. Results: The mean age of the patients was 7.13 +/- 2.45 years. A total of 92 patients were male, and 72 were female. Sixty percent of the patients had constipation for more than 6 months, and a negative association was found between constipation and bladder capacity (P = 0.000, r = -0.656). Rome III score was an independent predictor of severity of enuresis (P < 0.05). Constipated children were 1.47 times more likely to have severe enuresis than those not constipated (P = 0.002, 95% CI: 1.147-1.877). However, no significant relationship was observed between constipation and bladder residual urine volume (P = 0.725). Conclusion: Constipation was correlated with the severity of enuresis and bladder capacity. We strongly recommend careful inspection of constipation in each patient with enuresis.