Background: Dyspepsia is a common gastrointestinal complaint globally, affecting approximately 21.8% of the population. Among patients presenting with dyspeptic symptoms, over 80% are diagnosed with functional dyspepsia (FD), while approximately 16% are found to have chronic atrophic gastritis (CAG). CAG represents an important precancerous condition in the gastric cancer cascade, yet the relationship between pathologically confirmed CAG and dyspeptic symptoms remains poorly understood. The significant symptom overlap between CAG and FD creates diagnostic challenges in clinical practice. Study

Objectives: The primary objective is to determine whether there are significant differences in the prevalence and severity of dyspeptic symptoms (including epigastric pain, burning sensation, early satiety, and postprandial fullness) between patients with pathologically confirmed CAG and those without CAG (non-CAG group) among individuals who present with endoscopic features suggestive of atrophic gastritis. Secondary objectives include: (1) analyzing the independent effects of various covariates (Helicobacter pylori infection, dietary habits, sleep quality, psychological factors) on dyspeptic symptoms; (2) developing a symptom-based predictive model for pathological CAG; and (3) conducting exploratory serum metabolomics analysis to identify potential biomarkers and metabolic pathways associated with FD symptoms. Study

Design: This is a single-center, prospective, observational study conducted at the Third Affiliated Hospital of Zhejiang Chinese Medical University. The study will enroll approximately 258-315 adult patients (aged 18-75 years) who undergo endoscopy showing features suggestive of CAG within the past year. All participants will undergo standardized 5-point gastric mucosal biopsy according to the Updated Sydney System. Based on histopathological results, patients will be classified into pathological CAG group (presence of gastric mucosal atrophy) or non-CAG group (absence of atrophy). The study aims to recruit at least 80 pathologically confirmed non-CAG patients for comparison. Study Procedures: After obtaining informed consent, all enrolled patients will complete a comprehensive assessment at baseline including: demographic information, medical history, endoscopy and pathology results, Gastrointestinal Symptom Scale (GOSS) questionnaire using a 7-point Likert scale, H. pylori infection status (serology), dietary habits assessment, Pittsburgh Sleep Quality Index (PSQI), Self-Rating Anxiety Scale (SAS), Self-Rating Depression Scale (SDS), and perceived stress evaluation. A subset of participants will provide fasting blood samples for non-targeted metabolomics analysis using liquid chromatography-mass spectrometry (LC-MS) to identify metabolites related to amino acids, organic acids, lipids, and neurotransmitter precursors. This is a non-interventional study with all data and sample collection completed at enrollment without long-term follow-up. Primary Outcome: The primary outcome is the difference between pathological CAG and non-CAG groups in the prevalence and severity of dyspeptic symptoms, particularly cardinal FD symptoms (epigastric pain, burning, early satiety, postprandial fullness), assessed using the GOSS scale. A symptom score ≥4 on any cardinal symptom will define the presence of clinically significant FD symptoms. Expected Duration: The study is expected to last 24 months, including preparation, patient recruitment with data collection, and final statistical analysis and reporting phases. Significance: This study will provide evidence-based insights into the relationship between pathologically confirmed CAG and dyspeptic symptoms, potentially improving symptom management strategies and patient counseling. The metabolomics component may reveal novel biomarkers and pathways underlying symptom generation, laying groundwork for future mechanistic studies and personalized therapeutic approaches. Results will inform clinical practice and serve as preliminary data for larger-scale investigations.