Objective patterning of uroflowmetry curves in children with daytime and nighttime wetting

Pediatric uroflowmetry curve interpretation is incompletely standardized. Thus, we propose new, objective patterning.

Uroflowmetry curves were obtained in 100 children presenting with daytime incontinence or enuresis. Each curve was compared with a standard curve generated from a published nomogram and a new patterning method was formulated. Staccato and interrupted patterns were defined using International Children's Continence Society criteria. The remaining curves were divided by the deviation of the maximal flow rate from the median nomogram value as certain patterns, including tower-greater than 130%, not abnormal-70% to 130% and plateau-less than 70%. The correlation between the presenting symptom and patterns or other uroflowmetry parameters was evaluated. Six pediatric urologists also patterned the same curves subjectively.

All curves could be classified as 1 of the defined patterns using this method. Pattern distribution reflected the spectrum of presenting symptoms with more tower, interrupted and staccato patterns in children with daytime wetting than in those with monosymptomatic enuresis. Age adjusted voided volume was also smaller in the former group but post-void residual urine, and maximal and average flow rates did not correlate with presenting symptoms. Subjective patterning showed marked interobserver differences. When patterning applied by the current method was used as a reference, observer sensitivity for abnormal patterns inversely correlated with specificity.

Subjective uroflowmetry patterning is liable to personal bias. The proposed method enables objective patterning that complies with International Children's Continence Society standardization and clinical presentation.