Metagenomic Analysis of Gut Microbiota in Untreated and Uncontrolled Hypertensive Patients

Inclusion criteria

General Inclusion (applies to all participants)

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

Cohort-Specific Inclusion

A. Untreated Hypertension Group (Newly Diagnosed)

• 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.
• Never received any antihypertensive medication prior to enrollment.

B. Uncontrolled Hypertension Group (On Medication)

• Established hypertension, under stable antihypertensive therapy for ≥4 weeks.
• 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).
• No planned medication changes until stool sampling is completed.

C. Healthy Control Groups

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

Exclusion criteria

• Use of antibiotics, probiotics, or prebiotics within the previous 3 months, or bowel preparation for colonoscopy within 4 weeks.
• Chronic gastrointestinal diseases (e.g., inflammatory bowel disease, irritable bowel syndrome, celiac disease) or history of major gastrointestinal surgery (including bariatric surgery).
• 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.
• Pregnancy or lactation.
• Acute infection, acute gastrointestinal symptoms, or hospitalization within the past 4 weeks.
• Special restrictive diets (e.g., ketogenic, elimination, or medically prescribed weight-loss diets) or alcohol/substance abuse that may alter gut microbiota.
• Any other condition that, in the investigator's opinion, could interfere with participation, data integrity, or sample quality.