Effect of Home and Remote Blood Pressure Monitoring Via Home BP Monitoring System (HMS) on Adults With Hypertension in Taiwan

Design and setting:

This is a single-center, open-label, randomized, two-period, two-sequence crossover trial conducted at the cardiology outpatient clinics of National Taiwan University Hospital Hsin-Chu Branch, Hsinchu, Taiwan. Participants were randomized 1:1 to receive the case-manager intervention for months 0-6 followed by the control condition for months 6-12, or the reverse order. Crossover occurred at 6 months without a washout period.

Home monitoring common to both conditions:

At enrollment, every participant received an upper-arm Bluetooth blood pressure monitor (OMRON HEM-7157T) paired with the HMS smartphone application. The application transmitted every reading automatically, provided a log for medication intake and side effects, and delivered the same system-generated educational messages and reminders in both conditions. Participants were trained to follow the Taiwan 722 home blood pressure protocol in the first week of each month; measurement at other times was allowed.

Intervention condition (case-manager surveillance with physician-guided remote titration):

Cardiovascular case managers reviewed the transmitted readings at the beginning of each month against two targets: home blood pressure below 130/80 mmHg and self-reported medication adherence on more than 50% of days. A predefined algorithm specified: telephone counseling when participants measured on fewer than 4 days, reported adherence below 50%, or reported side effects; a clinic visit within 2 weeks for home blood pressure above 180/110 mmHg; doubling of the current dose or addition of a drug class when home blood pressure exceeded 135/85 or 145/90 mmHg, respectively, for 2 consecutive months; a change in dosing time or frequency for morning-only or evening-only elevation; and withdrawal of a drug class for home systolic blood pressure below 110 mmHg. All prescription changes were made by the cardiologist at a clinic visit, scheduled earlier when the algorithm required it, and recorded in the medical record.

Control condition (passive data review):

Readings were stored but not reviewed between visits. At each scheduled clinic visit, the treating cardiologist received a summary of the home readings from the preceding 2 weeks and adjusted treatment at his or her discretion.

Assessments:

Office blood pressure was measured at enrollment and at 3, 6, 9, and 12 months. 24-hour ambulatory blood pressure monitoring, brachial-ankle pulse wave velocity, and blood and urine tests were performed at enrollment and at approximately 6 and 12 months. Medication changes, side-effect reports, and health care use were recorded throughout.

Analysis:

Treatment effects are estimated as the 6-month (period 1) difference between randomized sequences, adjusted for baseline values, and as the within-participant crossover treatment effect using the 6- and 12-month values. The sequence effect is examined as an indicator of carryover.

This trial was registered retrospectively, after enrollment was completed.

• Case-manager surveillance with physician-guided remote titration (Other): Participants measure home blood pressure with an OMRON HEM-7157T Bluetooth monitor linked to the Home BP Monitoring System (HMS) app, following the Taiwan 722 protocol in the first week of each month. Case managers review the transmitted readings monthly against targets of home BP <130/80 mmHg and medication adherence >50% of days. A predefined algorithm guides telephone counseling (fewer than 4 measurement days, adherence <50%, or side effects), a clinic visit within 2 weeks (home BP >180/110 mmHg), dose doubling or addition of a drug class (home BP >135/85 or >145/90 mmHg for 2 consecutive months), dosing time or frequency changes (morning-only or evening-only elevation), and drug withdrawal (home systolic BP <110 mmHg). All prescription changes are made by the cardiologist at a clinic visit, scheduled earlier when needed.
• Passive data review at clinic visits (Other): Participants use the same monitor and app and follow the same 722 measurement protocol. Readings are stored but not reviewed between visits, and no case-manager contact is provided. At each scheduled clinic visit, the treating cardiologist receives a summary of the home readings from the preceding 2 weeks and adjusts treatment at his or her discretion. The app delivers the same system-generated education messages and reminders as in the intervention period.

Primary outcomes

• Office Systolic Blood Pressure [Baseline, month 6, month 12]: Office systolic blood pressure (mmHg) measured at the clinic visit, compared between the case-manager surveillance and passive data review conditions of the crossover design.
• Office Diastolic Blood Pressure [Baseline, month 6, month 12]: Office diastolic blood pressure (mmHg) measured at the clinic visit, compared between the case-manager surveillance and passive data review conditions of the crossover design.
• Home Systolic Blood Pressure [Baseline, month 6, month 12]: Mean home systolic blood pressure (mmHg), measured with the Omron HEM-7157T according to the 722 protocol: on 7 consecutive days at the start of each month, 2 sessions per day (morning and evening), 2 readings per session. Values are compared between the case-manager surveillance and passive data review conditions of the crossover design.
• Home Diastolic Blood Pressure [Baseline, month 6, month 12]: Mean home diastolic blood pressure (mmHg) measured with the Omron HEM-7157T according to the 722 protocol (7 consecutive days at the start of each month, morning and evening, 2 readings per session), compared between the case-manager surveillance and passive data review conditions of the crossover design.
• 24-Hour Mean Systolic Blood Pressure [Baseline, month 6, month 12]: Mean 24-hour systolic blood pressure (mmHg) on ambulatory blood pressure monitoring, compared between the case-manager surveillance and passive data review conditions of the crossover design.
• 24-Hour Mean Diastolic Blood Pressure [Baseline, month 6, month 12]: Mean 24-hour diastolic blood pressure (mmHg) on ambulatory blood pressure monitoring, compared between the case-manager surveillance and passive data review conditions of the crossover design.

Secondary outcomes

• Brachial-Ankle Pulse Wave Velocity [Baseline, month 6, month 12]: Brachial-ankle pulse wave velocity (m/s), measured with an automated oscillometric device, as a measure of arterial stiffness (target-organ damage).
• Number of Participants With Adverse Reactions Leading to Treatment Discontinuation [Up to month 12]: Participants with adverse reactions to antihypertensive treatment that led to discontinuation of a medication, recorded in the app or at clinic visits.
• Urine Albumin-to-Creatinine Ratio [Baseline, month 6, month 12]: Urine albumin-to-creatinine ratio (mg/g), as a measure of microalbuminuria (target-organ damage).
• ECG Voltage [Baseline, month 6, month 12]: Sokolow-Lyon voltage (SV1 + RV5 or RV6, mV) on 12-lead ECG, as a measure of left ventricular hypertrophy (target-organ damage).
• Adherence to the Home Blood Pressure Measurement Protocol [Weekly, from baseline to month 12]: Percentage of days per week on which both the morning and evening measurement sessions were completed, calculated from readings transmitted by the app.
• Retinal Nerve Fiber Layer Thickness [Baseline]: Average retinal nerve fiber layer thickness (µm) measured by optical coherence tomography, as a measure of retinal microvascular damage.
• Number of Cardiology Clinic Visits [Months 0-6 and months 6-12]: Number of cardiology outpatient visits per participant, from hospital records.
• Number of Emergency Department Visits [Months 0-6 and months 6-12]: Number of emergency department visits per participant, from hospital records.
• Number of Hospital Admissions [Months 0-6 and months 6-12]: Number of hospital admissions per participant, from hospital records.

Sex: All, ages: 18 Years to any

Inclusion Criteria:

* Willing to provide written informed consent.
* Age 18 years or older. Age 18 years or older. (Participants enrolled before approval of protocol version 4 in February 2023 were required to be 20 to 80 years old.)
* Patients receiving antihypertensive medication who have not achieved the treatment target of office blood pressure <130/80 mmHg, or patients with newly diagnosed hypertension with office systolic blood pressure of 140-180 mmHg and diastolic blood pressure of 90-110 mmHg (or 24-hour ambulatory blood pressure >130/80 mmHg).

Exclusion Criteria:

* End-stage, incurable disease with life expectancy of less than one year.
* Women who are pregnant, may be pregnant, or are breastfeeding.
* Dementia or loss of most self-care ability (ECOG performance status 2 or above).
* Office blood pressure >180/110 mmHg.
* Documented cardiac arrhythmia.
* Diagnosed secondary hypertension.
* Inability to use a smartphone.
* Acute cardiovascular event within the past six months, including stroke, decompensated heart failure, percutaneous coronary intervention, or coronary artery bypass graft surgery.

• Chih-Kuo Lee, MD, Principal investigator, National Taiwan University Hospital Hsin-Chu Branch