Effect of voiding position on uroflowmetric parameters and post-void residual urine volume in patients with benign prostatic hyperplasia

Objective: To investigate the effect of position on voiding using uroflowmetry and post-void residual (PVR) urine volume assessment in patients with lower urinary tract symptoms (LUTS) due to benign prostatic hyperplasia (BPH). Material and Methods: A total of 44 patients (mean age 61.7 years; range 47-72 years) with symptomatic BPH and 44 healthy men (mean age 60.3 years; range 40-67 years) who were used as controls were enrolled in the study. The uroflowmetric studies were performed in both standing and sitting positions. At least two measurements were obtained for both voiding positions for each participant. The PVR volumes were measured by means of a transabdominal ultrasound probe after each voiding. The maximum flow rate (Qmax), average flow rate (Qave), voided volume (VV) and PVR values were compared between the two different voiding positions. Results: The mean Qmax values for the standing and sitting positions in the patient group were 10.2 +/- 0.49 and 9.5 +/- 0.55 ml/s, respectively and the mean Qave values were 4.7 +/- 0.25 and 4.7 +/- 0.31 ml/s, respectively. The mean VV values for the standing and sitting positions in the patient group were 292.6 +/- 17.19 and 271.1 +/- 15.51 ml, respectively and the mean PVR values were 82.2 +/- 10.97 and 85.5 +/- 12.46 ml, respectively. The mean Qmax values for the standing and sitting positions in the control group were 24.8 +/- 0.78 and 25.3 +/- 0.78 ml/s, respectively and the mean Qave values were 13.2 +/- 0.36 and 13.5 +/- 0.33 ml/s, respectively. The mean VV values for the standing and sitting positions in the control group were 275.9 +/- 10.79 and 278.0 +/- 10.23 ml, respectively and the mean PVR values were 11.9 +/- 1.16 and 10.7 +/- 1.06 ml, respectively. There were no significant differences between voiding positions regarding the Qmax (p = 0.360), Qave (p = 0.978), VV (p = 0.355) or PVR (p = 0.842) values in the patient group. Similarly, there were no significant differences between voiding positions regarding the Qmax (p = 0.638), Qave (p = 0.537), VV (p = 0.890) or PVR (p = 0.412) values in the control group. Conclusion: The urinary flow rates and PVR urine volume do not seem to be affected by the voiding position (standing or sitting) either in patients with BPH or in healthy men.