Study design, materials and methods
The hospital-based samples comprised of 42 children with ADHD (aged between 6-12 years) at child and adolescent psychiatric clinics and 65 without the diagnosis of ADHD at Pediatric Urological clinics. We consecutively enrolled children diagnosed with ADHD.. Voiding dysfunction symptoms was assessed by the Dysfunctional Voiding Scoring System (DVSS) questionnaire. We compared the baseline data, DVSS score and uroflowmetry between two groups.The evaluation of LUTS was examined by urinalysis, renal echo, and Chinese version validated structured DVSS questionnaire, which has been validated for quantification of voiding symptoms in children
The demographic data, including age, height, weight, birth history, parental history, household income, and perinatal history were elicited by a specially trained interviewer. Uroflowmetric studies were then conducted. The subjects were instructed to drink water until a strong desire to void was achieved, and they were then instructed to void into a uroflowmeter. Voiding curves were classified as bell, tower, plateau, staccato and interrupted. All patterns except bell-shaped patterns were considered abnormal.
The baseline data of the study subjects are listed in Table 1. A total of 107 school-aged children, 42 with ADHD and 65 with non-ADHD were enrolled into the study. ADHD group had significantly lower maternal age than non-ADHD group (37.9±4.57 vs. 40.1±3.74, P=0.011).There were no significant differences between ADHD and non-ADHD group in terms of age, parental age, birth history, maternal history and household income. The total DVSS with subscale, flow rates and voided volume in subjects categorized by ADHD and non-ADHD group are shown. The mean total DVSS score in children of ADHD group was significantly higher than in subjects in non-ADHD group (8.24±6.09 vs. 6.09±4.65, P=0.042). In terms of mean scores of all DVSS subscales, the item “I cannot wait when I have to pee”, was significantly higher in the ADHD group (1.62±1.17vs. 0.90±1.09, p=0.002). Besides, significantly less voided volume were noted in ADHD group (73.8±3.58 vs. 100±7.57, p=0.045). The sleep quality of ADHD group was worse compared to non-ADHD group (sleep quality score, 2.88±2.00 vs. 1.91±1.86, p=0.013). There was no difference in constipation and enuresis between the two groups
Interpretation of results
In the present study, the prevalence rate of NE and/or daytime enuresis in patients with ADHD from the hospital-based sample was high (78.0%). Since participants with ADHD in child and adolescent psychiatric clinics were mostly referred by pediatricians or general practitioners from local hospitals, their ADHD symptoms might be more severe. Second, the participants in this study were younger and had more severe symptoms of ADHD. These different characteristics might explain the higher prevalence of NE in our study sample compared to that of other studies.
The role and importance of treatment for constipation in children with enuresis and dysfunctional voiding is well known. In the present study, The ADHD group had comparable constipation rate with non-ADHD group. As such, the presence and/or treatment of constipation did not play a role in explaining differences in treatment response between children with and without ADHD. Besides,
the sleep quality of ADHD group were significantly worse compared to non-ADHD group. We suggest that clinicians should evaluate the main sleep disorders for children with ADHD, which may be secondary to these sleep disturbances