Korean J Urol.  1998 May;39(5):476-479.

Adjusted Peak Urinary Flow Rate for Varying Age and Volume Voided in Healthy Korean Male

• Kim TH
• Yang DY
• Kim H

Abstract

PURPOSE: Peak urinary flow rate is a widely used parameter in the diagnosis and evaluation of treatment erect of BPH because of its objectiveness and non-in vasiveness. The peak urinary flow rate, however is different with each voided volume in the same patient and tends to decrease even in an asymptomatic man with increasing ages. Therefore we need an adjusted peak urinary flow rate corresponding with the age and voided volume. This adjusted peak urinary flow rate can be used to evaluate the voiding function more easily in the same patient periodically or In the different patient of various voided volume and ages.
MATERIALS AND METHODS
Data on age, volume voided and peak urinary flow rate were accumulated from 216 male aged from 10 to 80 who were free of voiding symptoms. All combinations of peak urinary flow rate, age and volume voided were tested for equation of bet fit by the least squares method with search for the equation providing least residual standard deviation with SAS package.
RESULTS
When the peak urinary flow rate is defined as a function of age and voided volume, the equation is Q=35.01+0.086A-0.0031A2-1612/V(Q: peak urinary flow rate, A: age, V: voided volume). At the point of population means for volume voided(247.5ml) arid age(35.2) the reference peak urinary flow rate was 27.7m1/sec. Adjusted peak flow rate can be obtained by subtracting the difference between the measured and expected peak flow rate(expected minus measured) from the reference peak flow rate. To make the adjusted peak flow rate obtained easily with measured peak flow rate, age and voided volume nomogram that incorporates the equation has been designed. In our nomogram an adjusted peak flow rate < 19.9 ml/sec or > 1.3 standard deviation below mean should be considered suspicious for obstruction.
CONCLUSIONS
Nomogram for adjusted peak flow rate that incorporates the age, voided volume and measured peak flow rate would be satisfactory for clinical use.

Keyword

Peak flow rate; Nomogram

MeSH Terms

Diagnosis
Humans
Least-Squares Analysis
Male*
Nomograms