Predisposing factors for positive D-Xylose breath test for evaluation of small intestinal bacterial overgrowth: A retrospective study of 932 patients

Table 1 Patient demographics

	+XBT			-XBT			P value
	n	mean	SD	n	mean	SD
Age contrasts (yr) (n = 932)	513	58.7	14.8	419	55.9	15.9	P = 0.10 (XBT)
Male:	56	59.6	15.9	148	60.3	16.3	P = 0.0025 (Gender)
Female:	457	58.6	14.7	271	53.4	15.2	P = 0.024 (Interact)
Overall mean: 57.4 overall SD: 15.4
BMI contrasts (n = 451)	244	24.1	5.90	207	29.5	7.33	P = 0.0050 (XBT)
Male: (n = 91)	23	24.3	5.65	68	28.8	6.96	P = 0.26 (Gender)
Female: (n = 360)	221	24.0	5.94	139	29.9	7.52	P = 0.42 (Interact)
Overall mean: 26.6 overall SD: 7.1
Gender contrast (n = 932)
Male, n (%)	56 (11)			148 (35)			P < 0.0001
Female, n (%)	457 (89)			271 (65)

XBT: D-Xylose breath test; BMI: Body mass index.

Table 2 Association of medical conditions and medications and small intestinal bacterial overgrowth n (%)

+XBT: 513	+XBT	-XBT	P value	OR (95%CI)
-XBT: 419	M: 56	M: 148		F:M
	F: 457	F: 271		4.46 (3.17-6.28)
	+PPI: 200	+PPI: 194
	-PPI: 313	-PPI: 225
GERD	171 (33)	113 (27)	0.04	1.35 (1.02-1.80)
	M: 22	M: 39
	F: 149	F: 74
	+PPI = 112	+PPI = 91
	-PPI = 59	-PPI = 22
Irritable bowel syndrome	77 (15)	47 (11)	0.09	1.40 (0.95-2.06)
	M: 3	M: 8
	F: 74	F: 39
	+PPI: 32	+PPI: 29
	-PPI: 45	-PPI: 18
PUD	51 (10)	17 (4)	< 0.01	2.61 (1.48-4.59)
	M: 6	M: 7
	F: 45	F: 10
	+PPI: 23	+PPI: 13
	-PPI: 28	-PPI: 4
Inflammatory bowel disease	20 (4)	12 (3)	0.39	1.38 (0.66-2.84)
	M: 2	M: 7
	F: 18	F: 5
Gastroparesis	52 (10)	22 (5)	< 0.01	2.04 (1.21-3.41)
	M: 5	M: 3
	F: 47	F: 19
Hypothyroidism	83 (16)	53 (13)	0.13	1.33 (0.91-1.93)
	M: 5	M: 8
	F: 78	F: 45
Diabetes mellitus	57 (11)	88 (21)	< 0.01	0.47 (0.33-0.68)
	M: 7	M: 33
	F: 50	F: 55
PPI	200 (39)	194 (46)	0.02	0.74 (0.57-0.96)
	M: 19	M: 69
	F: 181	F: 125
Narcotics	84 (16)	64 (15)	0.65	1.09 (0.76-1.55)
	M: 5	M: 23
	F: 79	F: 41
	+XBT: 45	+XBT: 36
	-XBT: 39	-XBT: 28
Steroids	36 (7)	14 (3)	0.01	2.18 (1.16-4.11)
	M:7	M: 9
	F: 29	F: 5
	+PPI: 20	+PPI: 8
	-PPI: 16	-PPI: 6
Anticholinergic drugs	52 (10)	38 (9)	0.58	1.13 (0.73-1.76)
	M: 1	M: 7
	F: 51	F: 31

Sub-analyses for gender and PPI were performed on those elements in Table 2 where the P value was below 0.05. Not a single subdivision by either gender or med PPI was associated with a significant difference in odds ratios between subsets. GERD: Gastroesophageal reflux disease; PUD: Peptic ulcer disease; PPI: Proton pump inhibitor; XBT: D-Xylose breath test.

Table 3 Association of previous abdominal surgical procedures (yes/no) with small intestinal bacterial overgrowth n (%)

Procedure	+XBT	-XBT	P value	OR (95%CI)
Gastric bypass	15 (3)	8 (2)	0.32	1.54 (0.65-3.69)
Hernia repair	14 (3)	25 (6)	0.01	0.44 (0.23-0.86)
Cholecystectomy	142 (28)	139 (33)	0.07	0.77 (0.58-1.02)
Appendectomy	106 (21)	67 (16)	0.07	1.37 (0.98-1.92)
Hysterectomy (females)	183 (40)	90 (33)	0.07	1.34 (0.98-1.84)

Limited patient numbers for Nissen Fundlopication (n = 17), Billroth I (n = 1) and Billroth II (n = 4) procedures. Subanalyses for gender performed on all elements of Table 3. Gender did not significantly alter the P value or odds ratio between subsets. XBT: D-Xylose breath test.