Accuracy of AOBP in a Chinese Population

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