Accuracy of AOBP in a Chinese Population

NCT ID: NCT03454178

Last Updated: 2025-12-15

Basic Information

• Recruitment Status: COMPLETED
• Total Enrollment: 149 participants
• Study Classification: OBSERVATIONAL
• Study Start Date: 2018-06-30
• Study Completion Date: 2019-12-29

Brief Summary

Background: Traditional office blood pressure (BP) measurement is often inaccurate and is inferior to out-of-office measurements, such as ambulatory blood pressure monitoring (ABPM), in predicting cardiovascular outcomes. A relatively new BP measurement method, called Automatic Office Blood Pressure measurement (AOBP), may provide similar BP readings to ABPM (latest clinical gold standard for BP measurements) and can easily be conducted in clinics. AOBP machines measure BP repeatedly 3-5 times with 1-min intervals and automatically provide the mean BP value. While AOBP was used in landmark trials (e.g. SPRINT trial) and was shown to eliminate white-coat effect, AOBP is rarely used in Hong Kong partly because there is no data concerning the accuracy of AOBP in Chinese. Almost all previous AOBP research used BpTRU (AOBP model), but BpTRU manufacturer was shut down permanently.

Aim: To assess if WatchBP Office (another AOBP model) has superior diagnostic accuracy than traditional office BP measurements, when compared to ABPM readings.

Method: 150 Chinese adult patients with a diagnosis of essential hypertension will be recruited consecutively from a Government-funded primary care clinic. All patients will have their BP measured by a 48-hour ABPM, a WatchBP office, and two traditional office blood pressure measurements.

ABPM will be considered the gold standard; sensitivity, specificity, positive and negative predictive values of AOBP and traditional BP to diagnose elevated BP level, masked hypertension and white-coat hypertension will be calculated and compared

Implication: if WatchBP provides closer BP readings to ABPM, this can lead to its implementation in routine clinical practice

Conditions

Hypertension

Study Design

• Observational Model Type: OTHER
• Study Time Perspective: PROSPECTIVE

Study Groups

Hypertensive patients

150 Chinese patients with a diagnosis of essential hypertension from a primary care clinic

WatchBP Office (BP measurement machine)

Intervention Type: DIAGNOSTIC_TEST

BP measurement: The nurse or assistant will leave the room after confirmed validity and the WatchBP will automatically measure BP for the participant at 1-minute intervals for 3 more readings; previous research showed that accurate BP readings could be obtained using 1-minute intervals. This is also the measuring method suggested by the manufacturer. The machine will automatically calculate the mean BP using the 3 readings. The mean BP value will be used for analysis. The diagnostic cutoff for diagnosing HT will be ≥135/85 for AOBP

Interventions

WatchBP Office (BP measurement machine)

BP measurement: The nurse or assistant will leave the room after confirmed validity and the WatchBP will automatically measure BP for the participant at 1-minute intervals for 3 more readings; previous research showed that accurate BP readings could be obtained using 1-minute intervals. This is also the measuring method suggested by the manufacturer. The machine will automatically calculate the mean BP using the 3 readings. The mean BP value will be used for analysis. The diagnostic cutoff for diagnosing HT will be ≥135/85 for AOBP

Intervention Type: DIAGNOSTIC_TEST

Eligibility Criteria

Inclusion Criteria

• diagnosis of essential hypertension

Exclusion Criteria

• (i) severe hypertension as defined by clinical systolic BP ≥180 mmHg and/or diastolic BP ≥110 mmHg (because they may need emergency treatment and it is unethical to delay such treatment due to the proposed project), (ii) inability to provide consent, (iii) pregnancy, (iv) night-time occupations (we need to compare AOBP and clinic BP readings to daytime ABPM average when the patient should be awake), (v) are occupational drivers (because potential dangers in driving could occur when patients are asked to remain still), (vi) receiving anti-coagulants (to prevent bruises when using ABPM), (vii) with known atrial fibrillation (as ABPMs and AOBP use have not been validated in this group)

• Minimum Eligible Age: 18 Years
• Eligible Sex: ALL
• Accepts Healthy Volunteers: No

Sponsors

Chinese University of Hong Kong

OTHER

Sponsor Role: lead

Responsible Party

Lee Kam Pui

Assistant Professor

Responsibility Role: PRINCIPAL_INVESTIGATOR

Locations

Lek Yuen Clinic

Hong Kong, , Hong Kong

Countries

Hong Kong

Other Identifiers

CUHK-188

Identifier Type: -

Identifier Source: org_study_id