Accepted for/Published in: JMIR mHealth and uHealth
Date Submitted: Nov 8, 2022
Date Accepted: Jul 21, 2023
Blood Pressure Measurement Based on the Camera and Inertial Measurement Unit of a Smartphone
ABSTRACT
Background:
Even though several mobile applications that can measure blood pressure (BP) have been developed, the data about the accuracy of those applications are limited.
Objective:
This study assessed the accuracy of AlwaysBP (test) in BP measurement compared with the standard cuff-based manual method of brachial BP measurement (reference). AlwaysBP is a smartphone software that estimates systolic BP (SBP) and diastolic BP (DBP) based on the pulse transit time (PTT). The PTT was calculated from the finger photoplethysmogram using the camera and from seismocardiogram using the inertial measurement unit sensor of a commercially available smartphone.
Methods:
A total of 87 participants without known cardiovascular disease were enrolled in the study. The primary analysis aimed to evaluate the accuracy of the test method compared with the reference method in the entire study population. The secondary analysis was performed to confirm the stability of the test method for up to 4 weeks in 15 subjects. At enrollment, the gender, arm circumference, and BP distribution were considered according to the current guidelines.
Results:
Among the study subjects, 45 (51.7%) individuals were male and the average age was 35.6 ± 10.4 years. Hypertension was diagnosed in 14 subjects (16.1%) prior to the study. The mean test and reference SBP were 120.0 ± 18.8 and 118.7 ± 20.2 mmHg, respectively, and the difference was 1.2 ± 7.1 mmHg (r = 0.935, P < 0.001). The mean test and reference DBP were 80.1 ± 12.6 and 81.1 ± 14.4 mmHg, respectively, and the difference was −1.0 ± 6.0 mmHg (r = 0.911, P < 0.001). At the 4-week time point, the differences between SBP and DBP were 0.1 ± 8.8 and −2.4 ± 7.6 mmHg.
Conclusions:
The AlwaysBP software exhibited acceptable accuracy regarding SBP and DBP measurement compared with the standard BP measurement method. This technology can be easily applied in everyday life and may improve the general population’s awareness of hypertension, thus helping to control it. Clinical Trial: none
Citation
Request queued. Please wait while the file is being generated. It may take some time.
Copyright
© The authors. All rights reserved. This is a privileged document currently under peer-review/community review (or an accepted/rejected manuscript). Authors have provided JMIR Publications with an exclusive license to publish this preprint on it's website for review and ahead-of-print citation purposes only. While the final peer-reviewed paper may be licensed under a cc-by license on publication, at this stage authors and publisher expressively prohibit redistribution of this draft paper other than for review purposes.