Helicobacter pylori eradication: Exploring its impacts on the gastric mucosa

Table 1 Major features of the eight trials examining for histological parameters

Ref.	Study arm, n		Follow-up, yr	Medication	Methods	Histologic parameter
	Eradicated	Not eradicated			1 = OS	AG						IM
					2 = RCT	Antrum			Corpus			Antrum			Corpus
						Before	After	P value	Before	After	P value	Before	After	P value	Before	After	P value
Sung et al[34]	226	245	1	OAC	2	0.64 ± 0.78	0.70 ± 0.82	P = 0.627	0.06 ± 0.31	0.02 ± 0.18	P = 0.682	0.78 ± 0.98	0.61 ± 0.94	P = 0.014	0.04 ± 0.32	0.06 ± 0.30	P = 0.391
Annibale et al[39]	25	7	0.5	BAM	1	0.56 ± 0.24	0.5 ± 0.2	NS	1.64 ± 0.11	1.36 ± 0.18	NS	0.58 ± 0.25	0.53 ± 0.23	NS	0.52 ± 0.13	0.76 ± 0.16	NS
Ohkusa et al[40]	115	48	1-1.25	PPI/A/C	1	0.8 ± 1	At 1–3 mo: 0.8 ± 1	P > 0.2	0.5 ± 0	At 1–3 mo: 0.3 ± 0	P = 0.020	0.7 ± 0	At 1–3 mo: 0.6 ± 0	P = 0.14	0.0 ± 0.0	At 1–3 mo: 0.2 ± 0	P = 0.022
							At 12–15 mo: 0.9 ± 1	P = 0.15		At 12–15 mo: 0.2 ± 0	P = 0.001		At 12–15 mo: 0.4 ± 0	P < 0.001		At 12–15 mo: 0.1 ± 0	P > 0.2
Lu et al[33]	92	62	3	O/LAC	1	1.25 ± 0.44	0.97 ± 0.83	P < 0.01	NA	NA	NA	0.64 ± 0.76	0.73 ± 0.77	NS	NA	NA	NA
Kang et al[41]	210	16	3	PPI/A/C	1	0.85 ± 0.06	1 yr: 0.83 ± 0.06	NS	0.70 ± 0.07	1 yr: 0.42 ± 0.06	P < 0.001	0.91 ± 0.07	1 yr: 0.83 ± 0.06	NS	0.60 ± 0.07	1 yr: 0.54 ± 0.06	NS
	54	16	3	PPI/A/C	1	0.96 ± 0.14	3 yr: 1.32 ± 0.20	NS	0.91 ± 0.20	3 yr: 0.45 ± 0.15	P = 0.033	1.02 ± 0.14	3 yr: 1.29 ± 0.14	NS	0.68 ± 0.15	3 yr: 0.83 ± 0.14	NS
Kodama et al[42]	118	21	8.6	PPI/A/C	1	1.60 ± 0.09	1.02 ± 0.08	P < 0.001	0.71 ± 0.10	0.02 ± 0.02	P < 0.001	0.60 ± 0.11	0.43 ± 0.09	NS	0.17 ± 0.12	0.00 ± 0.00	P < 0.05
Kodama et al[43]	176	21	10	PPI/A/C	1	AI: 1.39 ± 0.07	6 yr: 0.90 ± 0.09	P < 0.05	B1: 1.08 ± 0.08	1 yr: 0.78 ± 0.11	P < 0.05	A1: 1.14 ± 0.10	NA	NS	B1: 0.97 ± 0.09	6y: 0.42 ± 0.17	P < 0.05
						A2: 1.39 ± 0.06	1 yr: 1.06 ± 0.08	P < 0.01	B2: 0.52 ± 0.06	0.6 mo: 0.29 ± 0.07	P < 0.05	A2: 0.50 ± 0.07	NA	NS	B2: 0.13 ± 0.04	NA	NS
						IA: 1.51 ± 0.08	1 yr: 1.24 ± 0.09	P < 0.05				A1: 1.04 ± 0.09	NA	NS
Hwang et al[44]	442	91	10	PPI/A/C E/A/C/M	1	n = 178	n = 89 (50.0)	P = 0.002	n = 105	n = 72 (68.8)	P = 0.01	n = 221	n = 45 (20.4)	P = 0.002	n = 142	n = 31 (21.8)	P = 0.01

A: Amoxicillin; A1: Lesser curvature of the antrum; A2: Greater curvature of the antrum; B1: Lesser curvature of the corpus; B2: Greater curvature of the corpus; B: Bismuth subcitrate; C: Clarithromycin; E: Esomeprazole; GA: Gastric atrophy; IA: Lesser curvature of the angulus; IM: Intestinal metaplasia; L: lansoprazole; M: Metronidazole; NA: Not applied; NS: Not significant; O: Omeprazole; OS: Observational study; PPI: Proton pump inhibitor; RCT: Randomized controlled trial; data are presented as n (%) or the median ± standard deviation or mean ± SE/median.

Table 2 Major features of five meta-analyses

Ref.	Year	Total No. of study	Eradication group			Control group			OR/RR	95%Cl
			Total No.	Total events	Incidence rate	Total No.	Total events	Incidence rate
Sugimoto et al[118]	2020	4RCTs	2731	73	2.7%	2733	49	1.80%	0.67	0.47–0.96
Sugano et al[119]	2019	32	16301	316	1.90%	14805	535	3.60%	0.46	0.39-0.55
Doorakkers et al[120]	2016	8 Cohort	12899	119	0.90%	18654	208	1.10%	0.46	0.32-0.66
Chen et al[121]	2016	8RCTs	3992	74	1.90%	3962	116	2.90%	0.64	0.48-0.85
Ford et al[104]	2014	6RCTs	3294	51	1.60%	3203	76	2.40%	0.66	0.46-0.95

RR: Risk ratio; OR: Odds ratio; 95% C: 95% confidence interval.

Table 3 Studies on gastric microbiota alteration after eradication

Ref.	Year	Total subjects	Follow-up time	Age	Regimen	Study group		Main outcomes
				1 = Adults	1 = TT for 7-14 d	HEG	H. pylori (-)
				2 = Children	2 = QT for 10-14 d
Li et al[93]	2017	33	Day 0 and week 9	1	1	17	16	Bacterial diversity increased and the relative abundance of Helicobacter decreased, while the relative abundance of other phyla increased
Serrano et al[99]	2019	16	Day 0 and month 2	2	1	11	5	Bacterial diversity increased and the structures of the uninfected group were restored
Guo et al[98]	2020	164	Day 0 and month 6	1	2	115	49	Bacterial diversity returned to the level of the control group. The structure of the bacteria was different after treatment compared to the control group. Microbiota functional capacities were changed
He et al[86]	2019	17	Weeks 0, 6, and 26	1	2	10	NA	Bacterial diversity increased and structure and microbiota functional capacities were changed
Miao et al[82]	2020	55	Day 0 and week 4	2	1, 2 and STP	11	8	Diversity was similar compared to the control group. The bacterial structure became close to controls
Sung et al[35]	2020	102	Day 0 and 1 year	1	1	102	NA	Bacterial diversity increased and structure was changed

HEG: Helicobacter pylori eradication group; H. pylori: Helicobacter pylori; NA: Not applicable; QT: Quadruple therapy; TT: Triple therapy; STP: Sequential therapy with proton pump inhibitor and amoxicillin.