Data from frequency-volume charts versus maximum free flow rate, residual volume, and voiding cystometric estimated urethral obstruction grade and detrusor contractility grade in men with lower urinary tract symptoms suggestive of benign prostatic hyperplasia

Abstract

Aims: To examine associations of data from frequency-volume charts with maximum free flow rate, residual volume, and voiding cystometric estimated urethral obstruction grade and detrusor contractility in men with lower urinary tract symptoms suggestive of benign prostatic hyperplasia (BPH).

Methods: The 160 men included in the study met the criteria of the International Scientific Committee on BPH, i.e., they voided more than 150 mL during uroflowmetry, their residual volume and prostate size were estimated, and they completed frequency-volume charts correctly. From the frequency-volume charts, voiding habits and fluid intake were evaluated. Pressure-flow studies were performed as well.

Results: Increasing residual volume was related to a decrease of maximum voided volume and to a decrease of maximum free flow rate. Cystometric capacity was little affected by residual volume. Low contractility did not result in high residual volume. A marked decrease in voided volumes with increasing obstruction grade was observed, due to a decrease of cystometric capacity and an increase of residual volume. Detrusor contractility was little associated with voided volumes. A higher voiding frequency was related to a higher fluid intake. However, increased standardized frequency (number of voidings per 1,000 mL) was associated with a substantial reduction of fluid intake.

Conclusions: Infravesical obstruction is the most important factor influencing voided volumes, cystometric capacity, and residual urine volume. Frequency of voiding was not influenced significantly because patients with small voided volumes minimized their fluid intake.