The aim of the study was to determine the accuracy of the Microlife WatchBP O3 monitor for ambulatory blood pressure (BP) measurement according to the new ISO81060-2 2018 protocol.
The WatchBP O3 was first tested in 97 subjects from the general population (mean age, 71.3 years; 48 men) using four cuffs of different sizes. In a second study, 36 subjects (mean age, 72.9 years; 18 men) underwent stress testing on a cycle ergometer in order to increase their heart rate by 15% or more.
In the general population, the mean device–observer difference was 1.3 ± 3.2 mmHg for systolic BP and was 0.7 ± 3.2 mmHg for diastolic BP. These data were in agreement with criterion 1 of the protocol standard requirements (≤5 ± 8 mmHg). Also, criterion 2 was satisfied being the SDs of the 97 participants well below the maximum values required by the protocol (6.82 and 6.90 mmHg, respectively). During the ambulatory monitoring study, the average heart rate increase was 20.3% (range 15.4–28.9%). The mean device–observer difference was 1.5 ± 2.8 mmHg for systolic BP and was 1.7 ± 2.6 mmHg for diastolic BP. Also, these data were in agreement with criterion 1 of the protocol.
These data show that the Microlife WatchBP O3 monitor satisfied the ISO 81060-2:2018 standard requirements for a general population across a wide range of arm sizes and that also the protocol criteria for validation of devices intended for ambulatory BP monitoring were fulfilled.