Association between autoimmune gastritis and gastric polyps: Clinical characteristics and risk factors

Table 1 Baseline data showing the demographic data, clinical, biochemical, and histological characteristics of autoimmune gastritis patients

Characteristics
Patients (N)	530
Age (year), median (IQR)	59 (48-67)
Sex (female), n (%)	362 (68.30)
PCA positivity, n (%)	415 (78.3)
IFA positivity, n (%)	131 (24.7)
HP infection positivity, n (%)	91 (17.2)
Anemia, n (%)	212 (40.0)
Iron deficiency anemia, n (%), mild/moderate/severe	163 (30.8), 135/22/6
Pernicious anemia, n (%), mild/moderate/severe	66 (12.5), 48/11/7
Gastrin-17 (pmol/L), median (IQR)	70.44 (18.30-112.97)
PG-I (μg/L), median (IQR)	30.67 (20.08-48.61)
PG-II (μg/L), median (IQR)	8.07 (6.40-11.00)
PG-I/PG-II, median (IQR)	3.74 (2.05-6.20)
Vitamin B12 (pg/mL), median (IQR)	239.00 (136.20-355.50)
Norm, n (%)	331 (62.5)
Low level, n (%)	199 (37.6)
OLGA, n (%)
0	44 (8.3)
I	120 (22.6)
II	179 (33.8)
III	146 (27.6)
IV	41 (7.7)
OLGIM, n (%)
0	134 (25.3)
I	240 (45.3)
II	98 (18.5)
III	45 (8.5)
IV	13 (2.5)
ECL hyperplasia, n (%)	143 (27.0)
Absent	387 (73.0)
Linear	62 (11.7)
Micronodular	46 (8.7)
Macronodular	18 (3.4)
gNET	17 (3.2)

IQR: Interquartile range; PCA: Parietal cell antibodies; IFAs: Intrinsic factor antibodies; HP: Helicobacter pylori; PG: Pepsinogen; OLGA: Operative Link for Gastritis Assessment; OLGIM: Operative Link on Intestinal Metaplasia Assessment; ECL: Enterochromaffin-like; gNET: Gastric neuroendocrine tumor.

Table 2 Differences between patients with and without polyps

Group, n (%)	Gastric polyp, 166 (31.3)	Non-gastric polyp, 364 (68.7)	P value
Age (year), median (IQR)	61 (52.25-69)	58 (47-66)	0.006
Sex, n (%)	112 (67.5)	250 (68.7)	0.859
PCA positivity, n (%)	147 (88.6)	268 (73.6)	< 0.001
IFA positivity, n (%)	42 (25.3)	89 (24.5)	0.833
HP infection positivity, n (%)	24 (14.5)	67 (18.4)	0.264
Anemia, n (%)	70 (42.17)	159 (43.68)	0.302
Iron deficiency anemia, n (%), mild/moderate/severe	52 (31.33), 44/8/0	111 (30.49), 91/14/6	0.406
Pernicious anemia, n (%), mild/moderate/severe	18 (10.84), 14/3/1	48 (13.19), 34/8/6	0.851
Gastrin-17 (pmol/L), median (IQR)	91.9 (34.2-138.9)	60.9 (12.6-98.4)	< 0.001
PG-I (μg/L), median (IQR)	34.83 (22.8-45.7)	30.0 (18.1-58.2)	0.51
PG-II (μg/L), median (IQR)	8.8 (7.2-10.9)	7.8 (6.2-11)	0.019
PG-I/PG-II, median (IQR)	3.7 (2.4-5.0)	3.7 (1.9-6.7)	0.464
Vitamin B12 (pg/mL), median (IQR)	256.0 (130.0-357.2)	238.0 (137.0-354.5)	0.994
Norm/low level, n (%)	107 (64.46)/59 (35.54)	224 (61.54)/140 (38.46)	0.584
OLGA (0/I /II/III/IV)	11/34/39/61/21	33/86/140/85/20	< 0.001
OLGIM (0/I/II/III/IV)	38/63/39/21/5	96/177/59/24/8	0.018
ECL hyperplasia (absent/linear/micronodular/macronodular)	86/29/25/9	301/33/21/9	< 0.001

IQR: Interquartile range; PCA: Parietal cell antibodies; IFA: Intrinsic factor antibody; HP: Helicobacter pylori; PG: Pepsinogen; OLGA: Operative Link for Gastritis Assessment; OLGIM: Operative Link on Intestinal Metaplasia Assessment; ECL: Enterochromaffin-like.

Table 3 Pathological characteristics and distribution of gastric polyps

Pathology	HPs	Fundic polyps	gNET	Adenomas/LGD	Adenocarcinoma
Patients (n)	109	18	17	6	16
Polyps (n)	295	54	50	11	23
Diameter (mm), median (IQR)	5 (2-30)	2.5 (2-20)	5 (2-15)	12.5 (4-25)	20 (7-50)
Median number (IQR)	2 (1-3)	1.5 (1-3)	3 (1-4)	1 (1-3)	1 (1-1.25)
Single	49	9	6	5	12
Multiple	60	9	11	1	4
Distribution
Fundus	34	49	1	1	0
Corpus	223	5	48	4	13
Caria	10	0	0	1	1
Antrum	28	0	1	0	9
OLGA (0/I/II/III/IV)	6/18/28/43/14	4/7/2/4/1	0/2/2/10/3	0/3/1/1/1	1/4/6/3/2
OLGIM (0/I/II/III/IV)	26/39/29/13/3	7/6/3/2/0	3/6/3/5/0	1/4/0/0/4	1/9/4/1/1
ECL hyperplasia
Absent	61	12	0	4	9
Linear	22	1	0	2	4
Micronodular	19	3	0	0	3
Macronodular	7	2	0	0	0
gNET	0	0	17	0	0

HP: Helicobacter pylori; gNET: Gastric neuroendocrine tumor; LGD: Low-grade glandular dysplasia; IQR: Interquartile range; OLGA: Operative Link for Gastritis Assessment; OLGIM: Operative Link on Intestinal Metaplasia Assessment; ECL: Enterochromaffin-like.

Table 4 Pathological characteristics and distribution of gastric polyps

Pathology	Gastric polyp groups (n = 166, N = 4331)					P value
	HPs	Fundic polyps	gNET	Adenomas/LGD	Adenocarcinoma
Age (year), median (IQR)	59 (51-67)	56.5 (44.5-71.2)	63 (56-72)	67 (62.8-71.2)	67.5 (61.2-71)	0.012
Sex (female), n (%)	75 (68.8)	12 (66.7)	15 (88.2)	4 (66.7)	6 (37.5)	0.041
PCA positivity, n (%)	94 (86.2)	15 (83.3)	15 (88.2)	5 (83.3)	15 (93.8)	0.904
IFA positivity, n (%)	26 (23.9)	6 (33.3)	3 (17.6)	2 (33.3)	8 (50)	0.185
HP infection positivity, n (%)	10 (9.2)	4 (22.2)	1 (5.9)	0 (0)	9 (56.2)	< 0.001
PG-I (μg/L), median (IQR)	33.3 (25-42.8)	38.2 (24.5-48.3)	37.8 (24.1-57.2)	11.5 (11-19.8)	37 (25.8-43.9)	0.033
PG-II (μg/L), median (IQR)	8.8 (7.2-11)	9.3 (7.1-10.4)	9.3 (7.5-10.6)	7.8 (7.1-8.7)	8.1 (7-10.4)	0.919
PGI/II, median (IQR)	3.7 (2.5-4.9)	3.8 (2.1-5.1)	4.4 (2.7-5.2)	1.4 (1.2-1.9)	4.5 (3.3-6.2)	0.06
Gastrin-17 (pmol/L), median (IQR)	91 (69.2-136.4)	81.9 (35.2-117.7)	137.7 (113-176.9)	95 (75.7-109.2)	96.7 (59.1-137.1)	0.013
Vitamin B12 (pg/mL), median (IQR)	264 (154-352)	257.5 (140-361.8)	210 (82-320)	144 (102-301.5)	256.5 (98.5-360.8)	0.71
Anemia, n (%)	38 (34.9)	9 (50)	5 (29.4)	4 (66.7)	5 (31.2)	0.35

¹The total number of polyps.

HP: Helicobacter pylori; gNET: Gastric neuroendocrine tumor; LGD: Low-grade glandular dysplasia; IQR: Interquartile range; PCA: Parietal cell antibodies; IFA: Intrinsic factor antibody; PG: Pepsinogen.

Table 5 Univariate and multivariate analysis of the characteristics most associated with the development of gastric polyps in patients with autoimmune gastritis

Variable	Univariate analysis (95%CI)	P value	Multivariate analysis (95%CI)	P value
Age	1.023 (1.007-1.038)	0.003	1.015 (0.998-1.033)	0.084
Sex
Male	1.057 (0.714-1.566)	0.781	1.019 (0.656-1.582)	0.933
Female
PCA
Positive	2.771 (1.629-4.716)	< 0.001	2.003 (1.130-3.549)	0.017
Negative
IFA
Positive	1.047 (0.685-1.599)	0.833	0.866 (0.538-1.394)	0.553
Negative
HP infection
Positive	0.749 (0.451-1.244)	0.265	0.897 (0.512-1.571)	0.704
Negative
Anemia
Yes	0.819 (0.561-1.196)	0.302	0.811 (0.533-1.233)	0.326
No
Gastrin-17	1.007 (1.004-1.010)	< 0.001	1.002 (0.998-1.005)	0.306
PG-I	0.992 (0.985-0.998)	0.008	0.992 (0.985-0.999)	0.031
PG-II	1.037 (1.001-1.074)	0.044	1.053 (1.010-1.097)	0.015
PG-I/PG-II	0.927 (0.884-0.971)	0.002
OLGA
0-II
III-IV	2.408 (1.648-3.519)	< 0.001	1.541 (0.963-2.464)	0.071
OLGIM
0-II
III-IV	1.927 (1.107-3.353)	0.020	0.954 (0.487-1.869)	0.891
ECL hyperplasia
Absent
Exist	0.225 (0.150-0.338)	< 0.001	3.116 (1.868-5.197)	< 0.001

PCA: Parietal cell antibodies; IFA: Intrinsic factor antibody; HP: Helicobacter pylori; PG: Pepsinogen; OLGA: Operative Link for Gastritis Assessment; OLGIM: Operative Link on Intestinal Metaplasia Assessment; ECL: Enterochromaffin-like; CI: Confidence interval.

Table 6 Multivariate logistics regression analysis of the optimal subset method model

Variable	Coefficient	OR (95%CI)	P value
Age	0.015	1.015 (0.999-1.032)	0.071
PCA
Positive	0.778	2.178 (1.243-3.818)	0.007
Negative
PG-I/PG-II	-0.069	0.927 (0.884-0.971)	0.008
OLGA
0-II
III-IV	0.375	1.455 (0.945-2.239)	0.088
ECL hyperplasia
Absent
Exist	1.247	3.479 (2.242-5.399)	< 0.001
Intercept	-1.711	-	-

OR: Odds ratio; CI: Confidence interval; PCA: Parietal cell antibodies; PG: Pepsinogen; OLGA: Operative Link for Gastritis Assessment; ECL: Enterochromaffin-like.