Metagenomic Analysis of Gut Microbiota in Untreated and Uncontrolled Hypertensive Patients

Exploration of Microbial Patterns in Hypertension: A Cross-Sectional Analysis of Gut Microbiota in Newly Diagnosed Patients (MIPHYP-CROSS Study)

This observational study aims to explore the relationship between gut microbiota composition and blood pressure regulation in patients with hypertension. A total of 192 participants will be enrolled, including newly diagnosed untreated hypertensive patients, patients with uncontrolled hypertension under medication, and healthy controls. Fecal samples will be collected for metagenomic sequencing to identify microbial taxa and functional pathways associated with blood pressure levels. The findings are expected to reveal characteristic microbial patterns linked to hypertension and provide potential microbial targets for improving antihypertensive therapy.

Inclusion Criteria

General Inclusion (applies to all participants)

1. Adults aged 18 years or older.
2. Able and willing to provide a stool sample for gut microbiota analysis.
3. Able to understand and sign written informed consent prior to participation.

Cohort-Specific Inclusion

A. Untreated Hypertension Group (Newly Diagnosed)

1. Newly diagnosed hypertension, defined as: Office blood pressure ≥140/90 mmHg, confirmed by at least two measurements on separate visits; or 24-hour ambulatory BP monitoring (ABPM): mean ≥130/80 mmHg, or daytime ≥135/85 mmHg, or nighttime ≥120/70 mmHg.
2. Never received any antihypertensive medication prior to enrollment.

B. Uncontrolled Hypertension Group (On Medication)

1. Established hypertension, under stable antihypertensive therapy for ≥4 weeks.
2. Blood pressure not at target, defined as: Office BP ≥140/90 mmHg, or 24-hour ABPM mean ≥130/80 mmHg (daytime ≥135/85 mmHg, nighttime ≥120/70 mmHg).
3. No planned medication changes until stool sampling is completed.

C. Healthy Control Groups

1. No history of hypertension or antihypertensive medication use.
2. Office BP <130/80 mmHg (average of 2-3 readings).
3. Free from major chronic or gastrointestinal diseases.

Exclusion Criteria

1. Use of antibiotics, probiotics, or prebiotics within the previous 3 months, or bowel preparation for colonoscopy within 4 weeks.
2. Chronic gastrointestinal diseases (e.g., inflammatory bowel disease, irritable bowel syndrome, celiac disease) or history of major gastrointestinal surgery (including bariatric surgery).
3. Presence of major chronic diseases that may confound gut microbiota or blood pressure regulation, including: Coronary artery disease (CAD) or other significant cardiovascular diseases; Diabetes mellitus (type 1 or type 2); Chronic kidney disease (stage ≥3); Chronic liver disease or hepatic failure; Heart failure (NYHA class III-IV); Active malignancy or history of cancer within the past 5 years.
4. Pregnancy or lactation.
5. Acute infection, acute gastrointestinal symptoms, or hospitalization within the past 4 weeks.
6. Special restrictive diets (e.g., ketogenic, elimination, or medically prescribed weight-loss diets) or alcohol/substance abuse that may alter gut microbiota.
7. Any other condition that, in the investigator's opinion, could interfere with participation, data integrity, or sample quality.