Factors determining the amount of residual urine in men with bladder outlet obstruction: Could it be a predictor for bladder contractility?

Peer review under responsibility of Arab Association of Urology.

Figures & data

Figure 1 The ROC curve for PVR and BCI.

Table 1 The results for the different urodynamic variables in the three study groups.

Mean (SD) or n variable	Group A	Group B	Group C	P
No. of patients	30	30	21
Overactivity
−ve	10	7	13	CS 0.017^⁎
+ve	20	23	8
CS P1		0.390	0.044^⁎
CS P2			0.005^⁎
Capacity (mL)	230 (79)	342 (144)	543 (354)	KW < 0.001^⁎
MW P1		0.001^⁎	<0.001^⁎
MW P2			0.046^⁎
Compliance (mL/cmH2O)	18.2 (15.6)	15.8 (22.1)	12.9 (9.0)	KW 0.304
MW P1		0.128	0.497
MW P2			0.449
Voided volume (mL)	185 (86)	150 (103)	71 (41)	KW < 0.001^⁎
MW P1		0.147	<0.001^⁎
MW P2			0.017^⁎
Qmax (mL/s)	7.50 (2.60)	5.34 (3.06)	2.90 (0.90)	KW < 0.001^⁎
MW P1		0.004^⁎	<0.001^⁎
MW P2			0.002^⁎
Opening pressure (cmH2O)	81.7 (55.4)	116.2 (61.9)	83.9 (47.5)	KW 0.098
MW P1		0.010^⁎	0.114
MW P2			0.041^⁎
PdetQmax (cmH2O)	78.3 (42.1)	104.5 (55.3)	69.3 (16.3)	KW 0.026^⁎
MW P1		0.028^⁎	0.348
MW P2			0.018^⁎
Duration of contraction (s)	51.2 (26.7)	74.4 (45.8)	68 (53.4)	KW < 0.001^⁎
MW P1		0.020^⁎	0.455
MW P2			0.466
BCI	113.8 (26.5)	153.5 (43.6)	82.8 (16.6)	KW < 0.001^⁎
MW P1		< 0.001^⁎	< 0.001^⁎
MW P2			< 0.001^⁎
URF	30.6 (5.7)	67.2 (35.3)	77.5 (26.1)	KW < 0.001^⁎
MW P1		< 0.001^⁎	< 0.001^⁎
MW P2			0.094

P1, group A vs each other group.

P2, group B vs C.

KW, Kruskal–Wallis test.

CS, chi-squared test.

MW, Mann–Whitney test.

⁎ Statistically significant, P < 0.05.

Figure 2 The scatter plots of BCI and PVR, showing that most of the patients with good contractility (BCI ⩾ 100) were in the area with a PVR of <450 mL.