A comparative analysis of pediatric uroflowmetry curves

This study was conducted to try to objectify assessment of pediatric uroflowmetry curves.

Nine professionals in pediatric incontinence care judged 480 pediatric uroflows. On a 1-5 scale, where 1 = anomalous and 5 = normal, uroflows were assessed on four items: staccato, interrupted, flow time and obstruction. Eighty uroflows were re-evaluated for intra-observer agreement. After staccato and interrupted flow had been defined more sharply, another 100 uroflows were analyzed. Cohen's Kappa test for nominally classified data was applied to assess agreement. Kappa value of <0.20 denoted poor agreement, 0.21-0.40 fair, 0.41-0.60 moderate, 0.61-0.80 substantial and 0.81-1.0 perfect or almost perfect agreement. A second analysis was done using a 3 point scale, anomalous, intermediate and normal.

For interobserver agreement, Kappas were 0.45 for staccato flow, 0.67 for interrupted, 0.59 for flow time, and 0.66 for obstruction. For intra-observer agreement, Kappas were 0.47 for staccato, 0.65 for interrupted, 0.55 for flow time, and 0.65 for obstruction. On a three-point scale, anomalous, intermediate, and normal, interobserver agreement was equal to 0.80 or above. In the second 100 uroflows, the interobserver agreement Kappas were 0.44 for staccato, 0.95 for interrupted, 0.71 for flow time and 0.73 for obstruction.

Moderate to substantial agreement on uroflowmetry curves can be reached, except for staccato. Agreement increases if staccato and interrupted flows are defined more sharply. Staccato is defined as three or more peaks and troughs of more than the square root of maximal flow without touching 0, whereas interrupted flow needs at least one 0 passage. In a normal, uninterrupted uroflow, flow time is under 15  sec.