Is analysis of lower esophageal sphincter vector volumes of value in diagnosing gastroesophageal reflux disease?

Table 1 Demographic data for study cases

	Range	non-GERD mean ± SD	GERD mean ± SD
Age (years)	4-86	47.0 ± 16.1 (n = 308)	48.5 ± 14.9 (n = 319)
Weight (lbs)	87-397	173.6 ± 42.2 (n = 310)	190.2 ± 38.0 (n = 317)
Sex	F: 313 M: 314	F: 101 M: 80	F: 108 M: 162

Table 2 Summary of manometric data

	Normal range	Range of measurements	non-GERD mean±SD	GERD mean±SD	P	Sens.%	Spec.%
LESP	6.1-55.6	0-59.3	10.9 ± 8.4 (n = 319)	5.7 ± 4.8 (n = 308)	< 0.001	67.3	71.3
IVV	1855-10953	0-45830	4090 ± 4709 (n = 321)	1712 ± 080 (n = 306)	< 0.001	72.5	62.6
TVV	2060-14135	80-60740	5429 ± 5564 (n = 321)	2533 ± 2626(n = 306)	< 0.001	58.5	77.3
AL	1.0-5.0	0-9.8	2.6 ± 1.0 (n = 280)	2.2 ± 1.0 (n = 347)	0.013	4.5	98.4
OL	2.4-5.5	1.2-27.4	4.7 ± 1.8 (n = 287)	4.6 ± 1.4 (n = 340)	< 0.047	2.6	99
Any low	-	-	-	-	-	81.4	51
Allow	-	-	-	-	-	49.3	86.9

LESP = Lower esophageal sphincter resting pressure (mm-Hg), IVV = Intrabdominal vector volume (mm-Hg³), TVV = total vector volume (mm-Hg³), AL = abdominal length of the LES (mm), OL = overall length of the LES (mm). “Any-low” refers to cases where LESP, IVV or TVV are lower than normal. “All-low” refers to cases where LESP, IVV and TVV are all lower than normal. SD = Standard deviation, Sens. = Sensitivity, Spec. = Specificity. ‘P’ is the probability value from the chi-squared test for GERD vs. non-GERD; P < 0.05 is significant. Sensitivities and specificities are calculated using the lowest normal value.

Table 3 Logistic regression with the results of backward selection

Variable	Estimate	P
Intercept	+1.241	< 0.0001
LESP	-0.106	< 0.0001
IVV	-0.00019	< 0.0001
TVV	(rejected)	0.43
AL	(rejected)	0.089
OL	(rejected)	0.79
	Concordant = 76.1%
	Discordant = 23.6%
	Tied = 0.3%