Objective Vascular Biomarkers as Triage for Depression in Chronic Atrophic Gastritis

Implementing Objective Vascular Biomarkers as a Non-stigmatizing Triage Workflow for Depression in Gastroenterology Settings: a Multicenter Study Protocol for a Hybrid Effectiveness-implementation Study

Depressive symptoms are highly prevalent in patients with chronic atrophic gastritis (CAG) but are frequently under-detected due to stigma and reliance on subjective questionnaires. This multicenter, cross-sectional observational study aims to validate a novel clinical triage workflow. It repurposes routine vascular assessments (specifically dorsalis pedis artery ultrasound and arterial stiffness metrics) as objective "biological entry points" to facilitate mental health referrals. The study will enroll approximately 450-520 adults with histologically confirmed CAG across four clinical centers in China. The primary objective is to determine the diagnostic accuracy of these vascular biomarkers for identifying patients with moderate-to-severe depressive symptoms (PHQ-9 score >= 10). Secondary objectives include evaluating the implementation feasibility (e.g., referral uptake, screening completion rate) of this integrated care model in routine gastroenterology practice.

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:

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

Exclusion Criteria:

1. History of major psychiatric disorders (e.g., schizophrenia, bipolar disorder) or currently experiencing an acute psychotic episode.
2. Major cardiovascular or cerebrovascular events (e.g., acute myocardial infarction, stroke) within the past 3 months.
3. 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.
4. Severe hepatic or renal dysfunction, or malignancy with a limited life expectancy.
5. Current use of systemic corticosteroids or potent immunosuppressants.
6. Pregnancy or lactation.
7. Any other condition deemed by the investigators to interfere with study participation or cooperation.