Objective Vascular Biomarkers as Triage for Depression in Chronic Atrophic Gastritis

Current screening for depression in gastroenterology relies heavily on self-report scales, which are often limited by somatization and cultural stigma in Asian populations. This study proposes a "vascular-gut-brain" framework to bridge this service gap.

Participants will undergo a standardized multimodal assessment comprising:

• Gastrointestinal evaluation: Endoscopy and histopathology (OLGA/OLGIM staging), and symptom scoring (GSRS).

• Peripheral vascular assessment: High-frequency ultrasound of the dorsalis pedis artery (measuring Resistive Index [RI], Pulsatility Index [PI], and waveform classification).

• Arterial stiffness and autonomic function: Brachial-ankle pulse wave velocity (baPWV), Ankle-Brachial Index (ABI), and Heart Rate Variability (HRV).

• Psychological assessment: PHQ-9, GAD-7, and PSQI scales.

The study employs a hybrid effectiveness-implementation design. In addition to validating the diagnostic accuracy of vascular markers, the study will assess the feasibility of the workflow. A subset of participants will be re-contacted at 3 months to evaluate referral completion and retention rates. The ultimate goal is to establish a non-stigmatizing, objective triage protocol to improve mental health resource utilization in digestive clinics.

Inclusion criteria

• Age between 20 and 60 years, regardless of sex.
• Diagnosed with chronic atrophic gastritis (CAG) confirmed by upper gastrointestinal endoscopy and histopathology within the past 6 months.
• Ability to comprehend and voluntarily complete psychological assessments and multimodal vascular examinations.
• Willingness to provide written informed consent.

Exclusion criteria

• History of major psychiatric disorders (e.g., schizophrenia, bipolar disorder) or currently experiencing an acute psychotic episode.
• Major cardiovascular or cerebrovascular events (e.g., acute myocardial infarction, stroke) within the past 3 months.
• Severe peripheral artery disease or major anatomical abnormalities in the lower extremities (e.g., Fontaine stage III-IV, diabetic foot with ulcers) that would preclude reliable dorsalis pedis artery ultrasound assessment.
• Severe hepatic or renal dysfunction, or malignancy with a limited life expectancy.
• Current use of systemic corticosteroids or potent immunosuppressants.
• Pregnancy or lactation.
• Any other condition deemed by the investigators to interfere with study participation or cooperation.