Natural History, Evolution, and Clinical Features of Autoimmune Atrophic Gastritis (NH-GAA)

Autoimmune atrophic gastritis (AAG) is an immune-mediated disorder characterized by the loss of oxyntic glands and mucosal atrophy1.Specific autoantibodies directed to gastric parietal cells (PCA) and/or to intrinsic factors are inconstantly present1.Despite its morbidity, data on the epidemiology are scant. Its global prevalence has been estimated to be 0.5-4.5%.Hypo-achlorhydria and lack of intrinsic factor lead to malabsorption of many nutrients, as vit. B12, iron and calcium.A damage on elevated turnover cells may develop, affecting hemopoiesis, nervous system, gut, and myocardium, depicting a systemic disease.Moreover, one of the primary function of gastric acidity as a bactericidal defensive barrier is impaired resulting in both gastric and intestinal microbiota modification. It was recently shown that conditions causing hypo-achlorhydria modify the composition of microbiota from stomach to colon. In particular, at colonic level a decrease in the abundance of commensal bacteria associated to a reduction in microbial diversity and an increase of oral bacteria in the stool were shown.The clinical spectrum is unspecific, especially in early stages, leading to substantial diagnostic delay.Patients may be asymptomatic or complain of gastrointestinal manifestations such as atrophic glossitis, malabsorption, diarrhea, and dyspepsia.These symptoms are insufficient for the diagnosis.Neurological and psychiatric symptoms are often overlooked; myocardial infarction due to demand imbalance may occur.Most of AAG manifestations and complications are due to cyanocobalamin deficiency that may be clinically silent for years.Vit. B12 deficiency has also been associated with infertility, very early recurrent miscarriage, failure of assisted reproductive technologies, and neural tube defects.Furthermore, AAG is a preneoplastic condition as may predispose to the development of type I carcinoids and gastric adenocarcinoma.A previous publication of our group on the NH of AAG,showed that all patients evolved into a higher degree of gastric atrophy and/or metaplasia; additionally,6.3%of these patients developed a neoplastic complication (median time of 3 yo).These data underlined the need to feel the gap of knowledge in the identification and characterization of the factors promoting neoplastic development or associated with carcinogenesis.Moreover, strategies for prevention and management of non-neoplastic complications and extra-gastrointestinal manifestation have to be better determined Hence, a larger, prospective study looking at this issue is warranted.

Study Overview

• Status: Recruiting
• Conditions: Atrophic Gastritis

• Study Type: Observational
• Enrollment (Estimated): 600

Contacts and Locations

• Study Contact: Name: Emanuela Miceli, MD; Phone Number: +390382503545; Email: e.miceli@smatteo.pv.it

Study Locations

• Italy
  • Pavia
    • Pavia, Pavia, Italy, 27100
      • Recruiting
      • Fondazione IRCCS Policlinico San Matteo, SC Medicina Generale 1
      • Contact: Emanuela Miceli, MD; Phone Number: +390382503545; Email: e.miceli@smatteo.pv.it

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: Adult; Older Adult
• Accepts Healthy Volunteers: No

• Sampling Method: Non-Probability Sample

Study Population

Patients of both genders aged ≥ 18 years with atrophic gastritis being treated at Fondazione IRCCS Policlinico San Matteo

Description

Inclusion Criteria:

• Male or female, age ≥18 years;
• AAG diagnosis is made according to the updated Sydney System criteria referring to a tertiary outpatient clinic dedicated;
• Signed written informed consent.

Exclusion Criteria:

• Patients with uncertain histopathological findings;
• Patients with persistent or active Helicobacter pylori infection;
• Patients with long-term proton pump inhibitor users and atrophic pangastritis

Study Plan

How is the study designed?

Number of groups / cohorts

1

Cohorts and Interventions

Group / Cohort
We enroll all atrophic gastritis diagnosis is made according to the updated Sydney System criteria

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Clarify the natural history and the epidemiology of AAG in order to early diagnose patients, and to prevent irreversible complications	The incidence of oncological gastric complications occurring in all autoimmune gastritis patients (potential, mild, moderate, severe); The correlates of oncological complications, including laboratory markers, family history, autoimmune comorbidities, clinical features, so to identify clinical clusters and cluster-specific correlate.	Baseline visit: all patients will be evaluated and all laboratory test required for protocol will be performed. 6 months, patients will be evaluated, for symptoms associated to AAG with VAS scale. 12 months a last evaluation will be performed.

Collaborators and Investigators

• Sponsor: Fondazione IRCCS Policlinico San Matteo di Pavia

Study record dates

Study Major Dates

• Study Start (Actual): November 17, 2023
• Primary Completion (Actual): December 31, 2025
• Study Completion (Estimated): December 31, 2026

Study Registration Dates

• First Submitted: March 19, 2025
• First Submitted That Met QC Criteria: January 30, 2026
• First Posted (Actual): February 5, 2026

Study Record Updates

• Last Update Posted (Actual): February 5, 2026
• Last Update Submitted That Met QC Criteria: January 30, 2026
• Last Verified: February 1, 2025

More Information

Terms related to this study

• Additional Relevant MeSH Terms: Digestive System Diseases; Gastrointestinal Diseases; Stomach Diseases; Gastroenteritis; Gastritis; Gastritis, Atrophic
• Other Study ID Numbers: NH-GAA

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: NO

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No