The effect of voiding position on uroflowmetry findings of healthy men and patients with benign prostatic hyperplasia

We assessed the effect of different positions of voiding on uroflowmetry findings in healthy men and in patients with benign prostatic hyperplasia (BPH). Ten men with symptomatic BPH and 10 healthy men were enrolled in this study. Urodynamic study was done for each subject in 3 positions: standing, crouching (the position used in the Iranian style toilets), and sitting. The following urodynamic parameters were studied: voided urine volume, residual urine volume, total flow time, flow time, maximum flow rate, average flow rate, delay to start voiding, and maximum flow time. There were no significant differences between the 3 voiding positions and urodynamic parameters of healthy men. In men with BPH, the postvoid residual urine volume was significantly lower in the sitting position compared with the crouching and standing positions (67 mL versus 130 m/L and 130 mL; P < .001). The median average flow rate was 2.5 mL/s in the crouching, 3.5 mL/s in the sitting, and 3 mL/s in the standing positions (P = .016). Also, delay to start voiding was longest in the crouching position (6.5 seconds, 6 seconds, and 5 seconds in the crouching, sitting, and standing positions; P = .011). Voided urine volume, total flow time, flow time, maximum flow rate, and maximum flow time were not different among the 3 positions. In patients with BPH, voiding position may affect urodynamic parameters and the physician's decisions. Further studies are needed to elucidate the effects of voiding position on urodynamic parameters.