382 patients were enrolled in this retrospective study. All patients were conducted LBT for SIBO and examined by using colonoscopy for colonrectal polyps. Most of subjects had basic diseases (such as hypertension, type 2 diabetes, hyperlipidemia, fatty liver cirrhosis, functional constipation, chronic superficial gastritis, gastroesophageal reflux disease, peptic ulcer).
213 patients showed normal intestine mucosa. 169 patients had colorectal polyp (52 patients had inflammatory polyp, 29 had hyperplastic polyp, and 88 had adenomatous polyp). 136 polyps were ≤ 1.0cm, 25 polyps were between 1.0cm and 2.0cm, 8 polyps were ≥ 2.0cm. 71 patients had single polyp, 98 patients had multiple polyp. 114 patients had polyp on the left side colon (including sigmoid colon, descending colon, and rectum) and 55 patients had polyp on other parts of the colon.
- Prevalence of polyp in age and gender
The prevalence of colorectal polyp was significantly correlated with age. The average age of the colorectal polyp group was higher than control group (P=0.000). The prevalence of the colorectal polyp was increased with age (P=0.000). Male showed higher colorectal polyp prevalence than female (P=0.004). The data present in the table 1 and table 2.
Teble 1. The correlation of colorectal polys with age and gender
|
Polyp group
N=169
|
Control group
N=213
|
t/c2 value
|
P value
|
Age(Yr)
Sex (M/F)
|
62.14±11.663
108(63.9%)/61 (36.1%)
|
52.99±14.440
105(49.3)/108(50.7)
|
-6.855
8.153
|
0.000
0.004
|
Table 2. The prevalence of colorectal polys indifferent age groups
Age
|
Polyp %
|
Normal mucosa
|
c2 Value
|
P Value
|
18~45years
46~60years
>60years
|
11(15.7%)
65(43.3%)
93(57.4%)
|
59(84.3%)
85(56.7%)
69(42.6%)
|
34.527
|
0.000
|
- Correlation between colorectal polyp and SIBO
SIBO was diagnosed based upon North American Consensus’ suggestion and breath test manufacture’s suggestion. 146 patients had SIBO in colorectal polyp group (146/169, 86.4%),162 patients had SIBO in control group(162/213, 76.1%). Colorectal polyp patients had significant higher SIBO prevalence than control group (P=0.010).
Based upon small intestine hydrogen and methane production we divided the subjects into the following groups:
SIBO+: total LBT positive patients from both groups.
SIBO- : total LBT negative patients from both groups.
SIBO-M+: high methane production patients.
SIBO-M-: low methane production patients.
SIBO-H+: high hydrogen production patients.
SIBO-H-: low hydrogen production patients.
The prevalence of total SIBO patients, SIBO in high hydrogen production, and SIBO in high methane production in colorectal polyp group are significantly higher than that in control group. The data present on table 3.
Table 3 SIBO occurrence in colorectal polyp group and control group
|
Polyp group
169
|
Control group
213
|
C2 Value
|
P Value
|
SIBO+
|
146(86.4%)
|
162(76.1%)
|
6.558
|
0.010
|
SIBO-
|
23 (13.6%)
|
51(23.9%)
|
SIBO-M+
|
120(71.0%)
|
125(58.7%)
|
6.219
|
0.013
|
SIBO-M-
|
49 (29.0%)
|
88 (41.3%)
|
SIBO-H+
|
101(60.0%)
|
86(40.4%)
|
14.174
|
0.000
|
SIBO-H-
|
68 (40.0%)
|
127 (59.6%)
|
There is no significant correlation between SIBO and all types of polyps (including inflammatory polyp, hyperplastic polyp, adenomatous polyp). This finding suggests that the prevalence of SIBO is not correlation with the pathological classification of colorectal polyps.
- Correlation between colorectal polyp and constipation
We evaluated the correlation between colorectal polyps and constipation. The constipation was diagnosed according to the "Rome IV" criteria. The patients who had diarrhea had been excluded from this study. The colorectal polyp group showed higher constipation prevalence than control group (P=0.023). The data present in table 4.Table
4 incidence of constipation between polyp group and control group
|
Polyp group
N=129
|
Control group
N=160
|
c2 value
|
P value
|
Constipation
Normal bowel
|
38(29.5%)
91(70.5%)
|
29(18.1%)
131(81.9%)
|
5.150
|
0.023
|
- The correlation between breath hydrogen/methane and intestinal barrier function
311 of the 382 patients were evaluated for intestinal barrier function by testing Diamine oxidase, D-lactate and LPS. We divided the 311 patients into four groups according to their small intestine hydrogen and methane production.
HMPG: The high methane production group includes all the patients whose breath methane was over 10 ppm above fasting baseline within 90 minutes.
LMPG: The low methane production group includes all the patients whose breath methane was less than 10 ppm above fasting baseline within 90 minutes.
HHPG: The high hydrogen production group includes all the patients whose breath hydrogen was over 20 ppm above fasting baseline within 90 minutes.
LHPG: The low hydrogen production group includes all the patients whose breath methane was less than 20 ppm above fasting baseline within 90 minutes.
In this study, HHPG showed less intestinal barrier function damage than LHPG (c2=4.758,P=0.029). There is no significant difference between HMPG and LMPG in intestinal barrier function change (P=0.188).
The correlation data between breath hydrogen/methane and intestinal barrier function present in Table 5.
Table 5 Ccorrelation between intestinal barrier function and hydrogen/methane
|
intestinal barrier function damage
Yes No
|
c2 value
|
P value
|
HMPG
|
108(52.9%)
|
96(47.1%)
|
1.733
|
0.188
|
LMPG
|
65(60.7%)
|
42(39.3%)
|
|
HHPG
|
75(49.3%)
|
77(50.7%)
|
4.758
|
0.029
|
LHPG
|
98(61.6%)
|
61(38.4%)
|
The LPS level of HHPG is significantly lower than that of LHPG (t=1.974, P=0.049). The DAO and D-lac shows no difference between these two group patients. The data resent in table 6.
Table 6 Comparison of serological indexes of intestinal barrier between HHPG and LHPG
|
HHPG
N=152
|
LHPG
N=159
|
T value
|
P value
|
DAO (U/L)
D-lac (mg/L)
LPS (U/L)
|
5.89±7.26
15.51±8.95
8.42±8.79
|
5.10±7.80
15.95±8.90
10.57±10.34
|
-0.924
0.431
1.974
|
0.356
0.667
0.049
|
- The value of SIBO in predict colorectal polyp
We divided the SIBO positive patients into three groups based upon their hydrogen and methane production, then evaluated the sensitivity and specificity of each group. The data present in the table 7.
Table 7 The sensitivity and specificity of hydrogen and methane in predict colorectal polyp
|
Subject No.
|
Area Under Curve
|
P Value
|
95% CI
|
Sensitivity
|
specificity
|
SIBO-H+
|
59
|
0.454
|
0.373
|
0.353-0.555
|
39.8%
|
51.0%
|
SIBO-M+
|
117
|
0.525
|
0.568
|
0.440-0.610
|
63.2%
|
41.7%
|
SIBO-MH+
|
128
|
0.632
|
0.001
|
0.556-0.708
|
75.5%
|
51.0%
|
SIBO-H+:Hydrogen dominate SIBO.
SIBO-M+: Methane dominate SIBO.
SIBO-MH+: Combination of hydrogen and methane SIBO.