Convolutional Neural Network Model for Intestinal Metaplasia Recognition in Gastric Corpus Using Endoscopic Image Patches.

Gastric cancer (GC) is a significant healthcare concern, and the identification of high-risk patients is crucial. Indeed, gastric precancerous conditions present significant diagnostic challenges, particularly early intestinal metaplasia (IM) detection. This study developed a deep learning system to assist in IM detection using image patches from gastric corpus examined using virtual chromoendoscopy in a Western country. Utilizing a retrospective dataset of endoscopic images from Sant'Andrea University Hospital of Rome, collected between January 2020 and December 2023, the system extracted 200 × 200 pixel patches, classifying them with a voting scheme. The specificity and sensitivity on the patch test set were 76% and 72%, respectively. The optimization of a learnable voting scheme on a validation set achieved a specificity of 70% and sensitivity of 100% for entire images. Despite data limitations and the absence of pre-trained models, the system shows promising results for preliminary screening in gastric precancerous condition diagnostics, providing an explainable and robust Artificial Intelligence approach.

Italian guidelines for the diagnosis and management of colonic diverticulosis and diverticular disease.

Colonic diverticulosis and diverticular disease are among the most common gastrointestinal disorders encountered in clinical practice. These Italian guidelines focus on the diagnosis and management of diverticulosis and diverticular disease in the adult population, providing practical and evidence-based recommendations for clinicians. Experts from five Italian scientific societies, constituting a multidisciplinary panel, conducted a comprehensive review of meta-analyses, systematic reviews, randomised controlled trials, and observational studies to formulate 14 PICO questions. The assessment of the quality of the evidence and the formulation of the recommendations were carried out using an adaptation of the GRADE methodology. The guidelines covered the following topics: i) Management of diverticulosis; ii) Symptomatic uncomplicated diverticular disease: diagnosis and treatment; iii) Acute diverticulitis: diagnosis and treatment; iv) Management of diverticular disease complications; v) Prevention of recurrent acute diverticulitis; vi) Interventional management of diverticular disease.

Helicobacter Pylori infection in children with inflammatory bowel disease: a prospective multicenter study.

BACKGROUND: The relationship between Helicobacter-pylori(Hp)infection and inflammatory-bowel-disease(IBD) in pediatric-patients remains controversial. We aimed to assess the Hp-infection occurrence in newly-diagnosed pediatric-patients with IBD compared to no-IBD patients. Additionally, we aimed to examine differences in clinical-activity-index(CAI) and endoscopic-severity-score(ESS)between IBD-patients with and without Hp-infection, at baseline and at 1-year-follow-up(FU), after eradication-therapy(ET). METHODS: IBD diagnosis was based on Porto-criteria, and all patients underwent gastroscopy at baseline and 1-year FU. For Crohn's-disease(CD) and ulcerative colitis(UC), IBD-CAI and -ESS were classified using PCDAI/SES-CD and PUCAI/UCEIS, respectively. RESULTS: 76 IBD-patients were included in the study[35 F(46.1%),median-age 12(range 2-17)]. CD and UC were diagnosed in 29(38.2%) and 45(59.2%)patients, respectively, and unclassified-IBD in two(2.6%)patients. Non-IBD patients were 148[71 F(48.0%),median-age 12(range 1-17)]. Hp-infection at baseline was reported in 7(9.2%) and 18(12.2%)IBD and non-IBD patients, respectively(p = 0.5065). The 7 IBD patients with Hp infection were compared to 69 IBD patients without Hp-infection at baseline evaluation, and no significant differences were reported considering CAI and ESS in these two groups. At 1-year FU, after ET, IBD patients with Hp infection improved, both for CAI and ESS, but statistical significance was not reached. CONCLUSION: The occurrence of Hp-infection did not differ between IBD and no-IBD patients. No differences in CAI or ESS were observed at the diagnosis, and after ET no worsening of CAI or ESS was noted at one-year FU, between Hp-positive and -negative IBD patients.

Distinguishing features of autoimmune gastritis depending on previous H. pylori infection or positivity to anti-parietal cell antibodies: results from the Autoimmune gastRitis Italian netwOrk Study grOup (ARIOSO).

OBJECTIVES: To describe the clinical features and the risk of developing gastric tumors in patients with autoimmune gastritis (AIG). METHODS: This was a retrospective, longitudinal, multicenter study conducted at eight Italian tertiary referral centers. We retrieved clinical data from all histologically proven AIG patients. Differences between H. pylori-exposed vs H. pylori-naïve, and anti-parietal cell antibody (PCA)-positive vs PCA-negative patients were investigated. The rate of gastric adenocarcinoma and type 1 gastric neuroendocrine neoplasm (gNEN) was assessed. A multivariable model for factors associated to gNEN was fitted. RESULTS: 1598 patients with AIG (median age 58 years, IQR 46-68; F:M ratio 2.7:1) were included. H. pylori-naïve patients were more likely to have a first-degree family history of AIG (14.7% vs 8.9%; p=0.012), type 1 diabetes mellitus (4.9% vs 2.3%; p=0.025), and pernicious anemia (30.9% vs 21.1%; p=0.003). PCA-positive patients had significantly more associated autoimmune diseases (59.0% vs 42.9%; p<0.001) and were more likely to have been diagnosed by a case-finding strategy (15.3% vs 2.6%; p<0.001). Overall, 15 cases (0.9%) of gastric adenocarcinoma and 153 cases (9.6%) of gNEN occurred, with a global rate of 0.12 (95% CI 0.07-0.20) and 1.22 (95% CI 1.03-1.42) per 100 person/year, respectively. Having a vitamin B12/iron deficiency manifestation at AIG diagnosis was associated with an 16.44 (95% CI 9.94-27.20 p<0.001) hazard ratio of gNEN. CONCLUSIONS: The "pure" AIG pattern has typical features of an autoimmune disease and seems to be unrelated to H. pylori. In a tertiary referral setting, the risk of developing overt gastric adenocarcinoma is low, while patients with vitamin B12 deficiency complications at onset may benefit from a more intense endoscopic follow-up for early gNEN detection.

Unmet needs in treatment of symptomatic uncomplicated diverticular disease and prevention of recurrent acute diverticulitis: a scoping review.

Background: Diverticular disease (DD) represents a common gastrointestinal condition that poses a heavy burden on healthcare systems worldwide. A high degree of uncertainty surrounds the therapeutic approaches for the control of symptoms in patients with symptomatic uncomplicated diverticular disease (SUDD) and primary and secondary prevention of diverticulitis and its consequences. Objectives: To review the current knowledge and discuss the unmet needs regarding the management of SUDD and the prevention of acute diverticulitis. Eligibility criteria: Randomized trials, observational studies, and systematic reviews on lifestyle/dietary interventions and medical treatment (rifaximin, mesalazine, and probiotics) of SUDD or prevention of acute diverticulitis. Sources of evidence: The literature search was performed from inception to April 2023, without language restriction, following the modified Preferred Reporting Items for Systematic review and Meta-Analyses (PRISMA) reporting guidelines. References of the papers selected were checked to identify additional papers of potential interest. The final list of references was evaluated by a panel of experts, who were asked to check for any lack of relevant studies. Charting methods: Information on patient population, study design, intervention, control group, duration of the observation, and outcomes assessed was collected by two authors independently. Results: The review shows a high degree of uncertainty about therapeutic interventions, both dietary/lifestyle and pharmacological, in patients with SUDD, because of the scarcity and weakness of existing evidence. Available studies are generally of low quality, heterogeneous, and outdated, precluding the possibility to draw robust conclusions. Similarly, acute diverticulitis prevention has been seldom investigated, and there is a substantial lack of evidence supporting the role of dietary/lifestyle or pharmacological approaches to reduce the risk of diverticulitis. Conclusion: The lack of robust evidence regarding therapeutic options for gastrointestinal symptoms in SUDD patients and for primary and secondary prevention of acute diverticulitis remains an important unmet need in the management of DD.

Clinical Outcome of Patients with Gastric, Duodenal, or Rectal Neuroendocrine Tumors after Incomplete Endoscopic Resection.

Objectives: Our aim was to investigate the clinical outcome of patients with well-differentiated gastric, duodenal, and rectal neuroendocrine tumors after treatment with incomplete endoscopic resection due to the finding of microscopic positive resection margins (R1). Methods: This is a retrospective analysis of consecutive patients with type 1 gastric, non-ampullary non-functioning duodenal, or rectal neuroendocrine neoplasms with positive R1 margins after endoscopic resection. The rate of tumor recurrence and progression-free survival were considered to be the study's main endpoints. Statistical analysis was performed using MedCalc® v.17 software and a p-value of <0.05 was considered significant. A Cox proportional-hazard regression was performed to identify risk factors for disease recurrence/progression. Results: After evaluating 110 patients, a total of 58 patients were included in the final analysis (15 gastric NENs, 12 duodenal NENs, and 31 rectal NENs). After evidence of endoscopic R1 resection had been gathered, 26 patients (44.8%) underwent an endoscopic/surgical extension of the previous resection. Tumor progression (all local recurrences) occurred in five out of fifty-eight patients (8.6%) with a median PFS of 36 months. There were no tumor-related deaths. G2 grading and the gastric primary tumor site were the only features significantly associated with the risk of recurrence of the disease (HR: 11.97 [95% CI: 1.22-116.99], HR: 12.54 [95% CI: 1.28-122.24], respectively). Conclusions: Tumor progression rarely occurs in patients with microscopic positive margin excision (R1) after endoscopic resection and does not seem to affect patients' clinical outcomes.

Site and duration of abdominal pain discriminate symptomatic uncomplicated diverticular disease from previous diverticulitis patients.

Abdominal pain in patients with diverticular disease (DD) can be challenging in clinical practice. Patients with symptomatic uncomplicated diverticular disease (SUDD) and patients with a previous acute diverticulitis (PD) may share a similar clinical pattern, difficult to differentiate from irritable bowel syndrome (IBS). We used standardized questionnaires for DD (short and long lasting abdominal pain) and IBS (following Rome III Criteria) to assess clinical features of abdominal pain, in terms of presence, severity and length, in SUDD and PD patients. One hundred and forty-eight SUDD and 118 PD patients completed all questionnaires. Short-lasting pain was more frequent in SUDD than PD patients (p = 0.007). Number of long-lasting pain episodes was higher in SUDD (6.6 ± 11.9) compared to PD patients (3.4 ± 6.9) (p < 0.001). PD patients reported long-lasting pain more frequently in the lower left abdomen (p < 0.001), while in SUDD it was more frequently diffuse (p = 0.002) or localized in the lower right quadrant (p = 0.009). Features associated with long-lasting pain (fever, confinement to bed, consultations, antibiotic therapy, hospitalization) were more often reported in PD patients. IBS criteria were reported in 28.2% of patients and were more frequent in SUDD than PD patients (37.2% vs 17.1%, p < 0.001). SUDD and PD patients presented different pattern of abdominal pain (length, number of long lasting episodes, site and associated features), with a third reporting overlap with IBS. Further observational studies are needed to better characterize abdominal symptoms in DD patients, especially in those not fulfilling IBS criteria.Trial registration: The REMAD Registry is registered as an observational study in ClinicalTrial.gov (ID: NCT03325829).

Women in Gastroenterology: What Is the Current Situation? Results of an Italian National Survey.

BACKGROUND: Many women grow up dreaming of becoming doctors, preferring specialties that allow more focus on time outside the hospital and on family life. Nowadays, specialties, like gastroenterology, have still a significant gender gap. METHODS: Based on this known discrepancy, a web-based questionnaire was designed by the Young Component of the Scientific Committee of the Federation of Italian Scientific Societies of Digestive Diseases 2023 (FISMAD) to examine the current situation of female gastroenterologists in Italy. The survey, designed specifically for this study, was sent by email to all female gastroenterologists and residents gastroenterologists, members of the three major Italian societies of Gastroenterology. RESULTS: A total of 423 female physicians responded to the survey: 325 (76.8%) had full-time employment, and only a few had an academic career (7.2%). The main occupations were outpatient clinics (n = 288, 68%) and diagnostic endoscopy (n = 289, 68.3%); only 175 (41.3%) performed interventional endoscopy. One hundred and forty-seven (34.7%) had the chance to attend a master in advanced or interventional endoscopy, while 133 (31.4%) faced disadvantages that enabled them to attend. Of the 244 (58%) who reported feeling underappreciated, 194 (79.5%) said it was due to gender bias. We found that women doctors considered themselves disadvantaged compared with men doctors due to career opportunities (n = 338), salary negotiations (n = 64), and training opportunities (n = 144). CONCLUSIONS: In conclusion, gastroenterology still has a long way to go before approaching greater gender parity.

The 1st EoETALY Consensus on the Diagnosis and Management of Eosinophilic Esophagitis-Current Treatment and Monitoring.

The present document constitutes Part 2 of the EoETALY Consensus Statements guideline on the diagnosis and management of eosinophilic esophagitis (EoE) developed by experts in the field of EoE across Italy (i.e., EoETALY Consensus Group). Part 1 was published as a different document, and included three chapters discussing 1) definition, epidemiology, and pathogenesis; 2) clinical presentation and natural history and 3) diagnosis of EoE. The present work provides guidelines on the management of EoE in two final chapters: 4) treatment and 5) monitoring and follow-up, and also includes considerations on knowledge gaps and a proposed research agenda for the coming years. The guideline was developed through a Delphi process, with grading of the strength and quality of the evidence of the recommendations performed according to accepted GRADE criteria.This document has received the endorsement of three Italian national societies including the Italian Society of Gastroenterology (SIGE), the Italian Society of Neurogastroenterology and Motility (SINGEM), and the Italian Society of Allergology, Asthma, and Clinical Immunology (SIAAIC). The guidelines also involved the contribution of members of ESEO Italia, the Italian Association of Families Against EoE.

Type 3 gastric neuroendocrine neoplasms: the rising promise of conservative endoscopic management.

Gastric neuroendocrine neoplasms (g-NENs) are rare tumors arising from the gastric enterochromaffin-like cells. Recent data suggests an increased detection rate, attributed to more frequent esophagogastroduodenoscopies. While type 3 g-NENs were historically deemed aggressive, emerging research indicates potential for conservative management, especially endoscopic resection, in well-differentiated, small tumors. European guidelines now advocate for endoscopic intervention in selected cases, but North American guidelines remain more conservative. Key factors influencing outcomes are tumor size, grading, and depth of gastric wall infiltration. Endoscopic resection has shown promise for tumors confined to submucosal layers without lymphovascular invasion. Given the complexities, a multidisciplinary team approach is essential for management decisions. Current insights are largely based on retrospective studies, underscoring the need for prospective research to optimize endoscopic approaches.

The 1st EoETALY Consensus on the Diagnosis and Management of Eosinophilic Esophagitis - Definition, Clinical Presentation and Diagnosis.

Eosinophilic esophagitis (EoE) is a chronic type 2-mediated inflammatory disease of the esophagus that represents the most common eosinophilic gastrointestinal disease. Experts in the field of EoE across Italy (i.e., EoETALY Consensus Group) including gastroenterologists, endoscopists, allergologists/immunologists, and paediatricians conducted a Delphi process to develop updated consensus statements for the management of patients with EoE and update the previous position paper of the Italian Society of Gastroenterology (SIGE) in light of recent evidence. Grading of the strength and quality of the evidence of the recommendations was performed using accepted GRADE criteria. The guideline is divided in two documents: Part 1 includes three chapters, namely 1) definition, epidemiology, and pathogenesis; 2) clinical presentation and natural history, and 3) diagnosis, while Part 2 includes two chapters: 4) treatment and 5) monitoring and follow-up. This document has received the endorsement of three Italian national societies including the SIGE, the Italian Society of Neurogastroenterology and Motility (SINGEM), and the Italian Society of Allergology, Asthma, and Clinical Immunology (SIAAIC). With regards to patients' involvement, these guidelines involved the contribution of members of ESEO Italia, the Italian Association of Families Against EoE.

Endoscopic management of gastric, duodenal and rectal NETs: Position paper from the Italian Association for Neuroendocrine Tumors (Itanet), Italian Society of Gastroenterology (SIGE), Italian Society of Digestive Endoscopy (SIED).

The present paper reflects the position of the Italian Association for Neuroendocrine Tumors (Itanet), the Italian Society of Gastroenterology (SIGE), and the Italian Society of Digestive Endoscopy (SIED) regarding the management of patients affected by gastric, duodenal, and rectal neuroendocrine neoplasms (NENs) amenable to endoscopic treatment. The key questions discussed in this paper are summarized in Table 1. Data were extracted from the MEDLINE database through searches; expert opinions and recommendations are provided in accordance with the available scientific evidence and the authors' expertise. Recommendations are presented alongside a level of evidence and grade of recommendation based on the GRADE system. This paper specifically focuses on subgroups of NENs considered suitable for endoscopic management according to current international guidelines: i. well-differentiated gastric neuroendocrine tumors (gNET) type 1 < 2 cm and selected cases of type 3; ii. well-differentiated duodenal, non-functioning, non-ampullary NET with size < 2 cm; and well-differentiated rectal NET with size < 2 cm.

Gastric juice analysis in clinical practice: why, how, and when. The experience with EndoFaster.

Gastric juice analysis may be useful for clinical purposes, including the detection of H. pylori infection and diffuse atrophic gastritis on gastric mucosa. EndoFaster is a novel device which performs real-time analysis of gastric juice revealing the infection and hypochlorhydria by measuring ammonium concentrations and pH levels. This review aimed to evaluate the clinical applications of such a tool. By considering data from overall 11 studies, the values of sensitivity, specificity, positive predictive value, negative predictive value, accuracy, positive likelihood ratio, and negative likelihood ratio were 90%, 86%, 67%, 96%, 87%, 8.5, and 0.13, respectively, for H. pylori diagnosis, and 83%, 92%, 58%, 97%, 91%, 9.9 and 0.2, respectively, for suspecting diffuse atrophic gastritis. The very high value of negative predictive values for both H. pylori and mucosal atrophy would allow avoiding to perform useless negative gastric biopsies when the results of the test are negative. Some promising data suggest that gastric juice analysis may be useful also to diagnose H. pylori infection in patients with chronic active gastritis without evidence of bacteria at histology, as well as in predicting persistent acid reflux in patients on proton pump inhibitor therapy for reflux disease.

Systematic review and meta-analysis: Risk of gastric cancer in patients with first-degree relatives with gastric cancer.

BACKGROUND: Gastric cancer ranks fourth in terms of global cancer-related deaths. Timely identification of high-risk populations is crucial to reduce mortality. Although a family history of gastric cancer increases risk, European and British guidelines report weak recommendations and low-quality evidence about the management of these patients. AIM: To quantify the association in case-control studies of patients with gastric cancer with first-degree relatives with gastric cancer compared to those who do not. METHODS: We conducted a systematic review and meta-analysis of case-control studies up to November 2023. Data extraction was performed independently by two reviewers. The heterogeneity of effects across studies was quantified by I2 . We calculated odds ratios (OR) with 95% confidence intervals (CI) using random effects models. RESULTS: We included 30 studies in the systematic review. In all studies, a first-degree family history of gastric cancer represented a risk factor for gastric cancer. We included 21 studies on the risk of gastric cancer. There was a significantly increased association between gastric cancer and having first-degree relative(s) with gastric cancer, but with significant heterogeneity among studies (OR = 2.92; 95% CI 2.402-3.552; p < 0.001; I2 = 81.85%; p < 0.001). CONCLUSION: This meta-analysis highlights the relevance of patients' family history of gastric cancer and the importance of this risk factor for the early detection of neoplastic conditions.

Efficacy and Safety of Intravenous Ferric Carboxymaltose Treatment of Iron Deficiency Anaemia in Patients with Corpus Atrophic Gastritis: A Retrospective Study.

Corpus Atrophic Gastritis (CAG) is characterised by iron malabsorption leading to iron deficiency anaemia (IDA), which rarely responds to oral therapy. Ferric carboxymaltose (FCM), shown to be a safe and effective intravenous iron therapy in other diseases, has not been investigated yet in CAG. Thus, we aimed to assess the safety and efficacy of FCM in CAG-related IDA. A retrospective study on 91 patients identified CAG as the only cause of IDA treated with FCM. Twenty-three were excluded for incomplete follow-up. Sixty-eight were evaluated for safety and efficacy, while three were evaluated for safety only due to infusion interruption for side effects. Haemoglobin and iron storage were evaluated pre-infusion (T0), at 4 weeks (T4) and 12 weeks (T12) after infusion. An eventual IDA relapse was analysed. Two cases reported mild side effects. Haemoglobin significantly increased at T4, and T12, reaching +3.1 g/dL. Ferritin increased at T4, decreasing at T12, while transferrin saturation increased progressively until reaching a plateau. IDA relapsed in 55.4% of patients at a mean of 24.6 months. The only factor associated with relapse was female gender [OR (95% CI): 6.6 (1.5-28.6)]. FCM proved to be safe and effective in treating CAG-related IDA, ensuring quick and long-lasting recovery.

Update on Serum Biomarkers in Autoimmune Atrophic Gastritis.

BACKGROUND: Autoimmune atrophic gastritis (AAG) is a persistent, corpus-restricted immune-mediated destruction of the gastric corpus oxyntic mucosa with reduced gastric acid and intrinsic factor secretion, leading to iron deficiency and pernicious anemia as a consequence of iron and cobalamin malabsorption. Positivity toward parietal cell (PCA) and intrinsic factor (IFA) autoantibodies is very common. AAG may remain asymptomatic for many years, thus making its diagnosis complex and often delayed. Due to the increased risk of gastric neoplasms, a timely diagnosis of AAG is clinically important. CONTENT: The gold standard for AAG diagnosis is histopathological assessment of gastric biopsies obtained during gastroscopy, but noninvasive, preendoscopic serological screening may be useful in some clinical scenarios. Serum biomarkers for AAG may be divided into 2 groups: gastric autoimmunity-related biomarkers, such as PCA and IFA, and gastric corpus atrophy/reduced gastric acid secretion-related biomarkers, such as serum gastrin and pepsinogens. The present review focuses on the clinical significance and pitfalls of serum biomarkers related to gastric autoimmunity and gastric corpus atrophy, including some discussion of analytical methods. SUMMARY: Serum assays for PCA, IFA, gastrin, and pepsinogen I show good diagnostic accuracy for noninvasive diagnostic work-up of AAG. Diagnostic performance may increase by combining >1 of these tests, overcoming the problem of seronegative AAG. However, appropriately designed, comparative studies with well-characterized patient cohorts are needed to better define the reliability of these biomarkers in the diagnosis of patients with AAG. Currently, positive serum tests should always be followed by the state-of-art diagnostic test, that is, histopathological assessment of gastric biopsies obtained during gastroscopy to definitively confirm or rule out AAG and eventually neoplastic complications.

Common Diagnostic Challenges and Pitfalls in Segmental Colitis Associated with Diverticulosis (SCAD).

Segmental colitis associated with diverticulosis (SCAD) is characterized by inflammation involving the sigmoid inter-diverticular mucosa, sparing the proximal colon and rectum. Due to the heterogeneity of clinical manifestations and endoscopic and histological findings, SCAD diagnosis might be challenging in clinical practice. This narrative review aimed to report the SCAD diagnostic criteria adopted in different studies, highlighting the current challenges and main pitfalls in its diagnosis. We analysed fourteen studies, mainly prospective observational studies. Haematochezia and rectal bleeding were the main complaints leading to diagnosis, followed by diarrhoea. An accurate endoscopic description was performed in 86% of studies, while a standardised biopsy sampling protocol (sigma, proximal colon and rectum) was scarcely adopted, being complete only in 28.5% of studies. The evaluation of concomitant drugs potentially inducing colitis was carried out in only 57% of studies. Great heterogeneity in sigmoid endoscopic (edema, erythema, erosions, ulcers, mucosal friability) and histological findings (chronic and/or acute inflammatory infiltrate) was observed. We showed that SCAD diagnosis is often based on not fully adequate macroscopic colonic description and scant biopsy protocol sampling. An accurate clinical and endoscopic evaluation, with an adequate sampling biopsy protocol, with attention to differential diagnosis, seemed to be crucial for a prompt SCAD diagnosis.

Gastric Microbiota Gender Differences in Subjects with Healthy Stomachs and Autoimmune Atrophic Gastritis.

Gender differences and microbiota are gaining increasing attention. This study aimed to assess gender differences in gastric bacterial microbiota between subjects with healthy stomachs and those with autoimmune atrophic gastritis. This was a post hoc analysis of 52 subjects undergoing gastroscopy for dyspepsia (57.7% healthy stomach, 42.3% autoimmune atrophic gastritis). Gastric biopsies were obtained for histopathology and genomic DNA extraction. Gastric microbiota were assessed by sequencing the hypervariable regions of the 16SrRNA gene. The bacterial profile at the phylum level was reported as being in relative abundance expressed as 16SrRNA OTUs (>0.5%) and biodiversity calculated as Shannon-diversity index-H. All data were stratified for the female and male gender. Results showed that women with healthy stomachs had a higher gastric bacterial abundance and less microbial diversity compared to men. Likely due to hypochlorhydria and the non-acid intragastric environment, autoimmune atrophic gastritis seems to reset gender differences in gastric bacterial abundance and reduce biodiversity in males, showing a greater extent of dysbiosis in terms of reduced biodiversity in men. Differences between gender on taxa frequency at the phylum and genus level in healthy subjects and autoimmune atrophic gastritis were observed. The impact of these findings on the gender-specific natural history of autoimmune atrophic gastritis remains to be elucidated; in any case, gender differences should deserve attention in gastric microbiota studies.