Uroflowmetric differences between standing and sitting positions for men used to void in the sitting position

To compare the results of uroflowmetry in the standing and sitting position in men who void only in the sitting position.

Two hundred patients were subjected to pelvic ultrasonography while their bladders were full, and then after voiding. Uroflowmetry was done both in sitting and standing positions and compared for all patients. Further comparisons were made according to patients' age (below and above 50) and Qmax (at or below 15 mL per second versus greater than 15 mL per second). We performed statistical analysis using Wilcoxon matched-pairs signed-ranks test.

Comparison of uroflowmetric results in both positions showed no statistical differences except for significantly larger residual urine volume in the standing position (86.1 +/- 77) relative to the sitting position (73 +/- 80.2) (P = 0.04). On substratifying patients according to age, Qmax was significantly higher in the sitting position (16.6 +/- 8.94) relative to the standing position (15.2 +/- 7.5) in the young group (P = 0.02). Such a significant difference was not seen in the elder (greater than 50 years) group. In contrary to the low-flow group, cases with high flow showed significantly higher Qmax and Qave and significantly lower voiding and flow times and significantly lower residual urine volume in the sitting position.

Voiding in the sitting position showed significantly better flow rates than during standing in patients with higher flow and younger age. Moreover, postvoid residual was significantly less in the sitting position in the previous two groups and in the total groups of patients. On the contrary, the presence of low flow nullifies these uroflowmetric positional differences. Uroflowmetry should be always performed in the preferred position.