The Tzu Chi nomograms for maximum urinary flow rate (Qmax ) in children: comparison with Miskolc nomogram.

Abstract

To report the first ranking method-based age- and gender-specific nomograms for maximum urinary flow rate (Qmax ) in children. Healthy children aged 4-12 years were enrolled for two sets of uroflowmetry tests. The first and the higher value of the two consecutive Qmax of each child with a voided volume (VV) of ≥50 mL were included for establishing single- and dual-Qmax nomograms. Children with possible urinary tract infection or lower urinary tract dysfunctions were excluded. In all, 1128 children (583 boys and 545 girls) with a mean (sd) age of 7.7 (2.2) years were eligible for analysis and construction of nomograms. Multivariate analysis showed that the Qmax was significantly affected by age, VV and gender (all P < 0.01). The values of the corresponding percentile of the Qmax were significantly higher in the dual-Qmax nomogram compared with the single-nomogram. In boys aged 8-12 years, the 5th percentile line of the Miskolc nomogram was significantly lower than that of the present nomograms at all VVs. Minimally acceptable Qmax values, around the 10th percentile of the dual-Qmax nomogram, were >11.5 mL/s in children aged ≤6 years and >15.0 mL/s in children aged ≥7 years. External validation is required for the present dual-Qmax nomograms. We recommend repeating uroflowmetry in cases with a Qmax lower than the minimally acceptable age- and gender-specific Qmax values.