This cluster randomized controlled trial aims to evaluate the efficacy of a comprehensive intelligent hypertension management system (CHESS) in blood pressure lowering in primary health care (PHC) settings of China.

The trial aims to investigate the efficacy of a comprehensive digital intervention for hypertension treatment in cluster clinics. 40 PHC centers will be selected from different areas in China, and eligible patients being screened consecutively in each site, then all PHC centers will be randomized into intervention group and control group. The physicians and patients from the 20 intervention sites will receive training and support on the use of the CHESS system, and the control group will continue to receive usual care. The multi-faceted CHESS intervention includes: (1) home blood pressure monitoring (HBPM) for patients, and the data will be uploaded to central electronic health records (EHR) automatically; (2) a Smart Reminder and Alert System (SRAS) to send educational messages and reminders to support patients on HBPM, improve blood pressure medication adherence and lifestyle modification; (3) a decision support system (DSS) to provide physicians with antihypertensive medications prescriptions and referral recommendations; (4) regular quality assessment reports will be provided to health care providers automatically to improve the quality of hypertension management at PHC level. All participants will be asked to attend the clinic at least once every 3 months, and be followed up for 12 months.

Inclusion Criteria for Sites:

1. An electronic data collection system is routinely used at the clinic for hypertension management in PHC sites, and the distance between sites must be >2km;

2. At least one drug of each of the five classes of recommended antihypertensive medications is available at the clinic:

   • A: Angiotensin-converting enzyme inhibitors (ACEI; e.g., captopril or enalapril);
   • A: Angiotensin receptor blockers (ARB; e.g., losartan or valsartan)
   • B: β-blockers (e.g., atenolol, metoprolol, or bisoprolol)
   • C: Calcium antagonists (e.g., nitrendipine, nifedipine, or amlodipine)
   • D: Diuretics (e.g., hydrochlorothiazide, indapamide, or indapamide SR tablets)

3. Has an outpatient clinic for hypertension treatment and staff are willing to take part in the study.

Inclusion Criteria for Participants:

1. Age ≥35 years and <80 years
2. Local resident of the community/township who attends the PHC clinic for hypertension management, and will not travel for more than 3 months during the study period;
3. Established diagnosis of essential hypertension, with uncontrolled BP before randomization (defined as office BP≥140/90mmHg, and 24-hour ambulatory BP≥130/80mmHg);
4. Own and be able to use a smartphone daily;
5. Be willing to participate in the study and sign the informed consent.

Exclusion Criteria for participants:

1. Physician-diagnosed or suspected secondary hypertension (e.g. hypertension caused by renal disease, renal artery stenosis, aortic stenosis, primary aldosteronism, pheochromocytoma/paraganglioma, Cushing's syndrome, thyroid dysfunction, intracranial disease, drug- induced, or rare monogenic genetic disease), or the presence of other structural heart diseases, such as aortic insufficiency, hypertrophic cardiomyopathy, or congenital heart disease;
2. Office or ambulatory SBP≥180 mmHg and/or DBP≥110 mmHg before randomization;
3. Physician-diagnosed atrial fibrillation;
4. Physician-diagnosed CKD, estimated glomerular filtration rate (eGFR) <60 mL/min/1.73 m2 (if serum creatinine is available), or currently on dialysis treatment;
5. Physician-diagnosed hepatic dysfunction, or ALT≥ 2*ULN;
6. Currently at the unstable or terminal stage of any disease (e.g. new- onset cardiovascular and cerebrovascular diseases occurred within 3 months, malignant tumors);
7. Intolerance to at least two classes of antihypertensive medications among A, B, C or D;
8. Currently taking 3 or more antihypertensive drugs;
9. The subject is pregnant or breastfeeding, or planning to become pregnant or breastfeeding during the study period;
10. Have communication or cognitive disorders;
11. Be unwilling to take antihypertensive drugs, or assumed poor adherence to treatment;
12. The subject is participating in other clinical trials at the moment.