Table 4.

Multiple variable linear regression models to predict anal pressure during evacuation using anal pressures during a Valsalva maneuver

Comparisons	Predictor variables	Estimate (95% CI)	P value	Variance (%) explained by model; P value
Anal pressure during evacuation in constipation-abnormal BET and constipation-normal BET versus healthy women (Model 1)	Healthy women (Reference group)	NA	NA
	Constipation with normal BET	−10.9 (−34, 12)	0.34	41% <0.001
	Constipation with abnormal BET	−30.8 (−57, −5)	0.02
	Anal pressure (VM)	0.12 (−0.07, 0.3)	0.24
	Anal pressure (VM)*constipation with normal BET†	0.19 (−0.04, 0.4)	0.10
	Anal pressure (VM)*constipation with abnormal BET†	0.52 (0.3, 0.8)	<0.001
Anal pressure during evacuation in constipation-abnormal BET and healthy women vs constipation-normal BET (Model 2)	Constipated women (Reference group)	NA	NA
	Healthy women	8.67 (−14, 31)	0.25	41% <0.001
	Constipation with abnormal BET	−20.5 (−42, 0.8)	0.06
	Anal pressure (VM)	0.31 (0.2, 0.4)	<0.001
	Anal pressure (VM)*healthy women†	0.18 (−0.4, 0.06)	0.14
	Anal pressure (VM)*constipation with abnormal BET†	0.33 (0.1, 0.5)	0.001

BET – Balloon expulsion time; VM – Valsalva maneuver; CI – Confidence interval

^†Interaction terms