Frequency-volume chart data from incontinent children

Objective To establish the mean and standard deviation about the mean for voiding variables of incontinent children aged 6-11 years as measured on a frequency-volume chart (FVC), and to determine the effect. of type of incontinence, gender and age on these values. Patients and methods All children attending two continence clinics over a 3-year period completed a FVC as a routine part of their assessment. Voided volume and voiding interval data were collected from these charts. The mean maximum, mean minimum and overall mean voided volume and voiding interval were established for the whole group and then for each age, gender and type of incontinence. Results The voiding patterns of incontinent children were very variable and thus the standard deviation for each voiding parameter was large. Multivariate analysis showed that the only variable that affected any of these apparent storage parameters was the child's age; gender and type of incontinence did not influence bladder storage patterns. Children with day-time incontinence did not have smaller voided volumes than those with nocturnal enuresis. Conclusion Both the mean and the standard deviation about the mean of all voided volumes varied widely amongst incontinent children, Only age appeared to influence trends in voided volumes. Any clinical investigation using the FVC in children should consider the high standard deviation when calculating sample size.