ACCURACY AND FEASIBILITY OF SMARTWATCH-BASED CUFFLESS BLOOD PRESSURE MEASUREMENT: A REAL-WORLD PROSPECTIVE OBSERVATIONAL STUDY

Abstract

Copyright © 2022 Wolters Kluwer Health, Inc. All rights reserved.OBJECTIVE: Smartwatch-based blood pressure (BP) measurement will continue to grow in the near future. Recently, BP measurement using a photoplethysmography-based smartphone algorithm paired with a smartwatch is approved as a medical device. We aimed to evaluate the feasibility and measurement stability of the smartphone-based BP measurement. DESIGN AND METHOD: The Korean Society of Hypertension (KSH) hosted a one-month campaign entitled Daily BP measurement with your Galaxy Watch, and collected the real-world data of smartwatch-based BP measurement. We evaluated the clinical characteristics and blood pressure variability according to measurement timing. Furthermore, we investigated the measurement stability following calibration process. RESULTS: We collected 35,646 BP measurement data from 767 participants. Mean age of the participants were 43.72 ± 11.89 years and 80.26% were men. Each participant had an average of 1.50 ± 1.31 BP measurements per day, and 19.74% of the participants measured their BP every day. BP values showed large variability, higher on Monday than those on other days in a week and the lowest from midnight to 4 a.m. highest from noon to 4 p.m., and decreased toward midnight during a day. The degree of measurement error by calibration defined as a BP difference between the measurement values seven days before and after calibration was 6.78 ± 5.58 mmHg. Higher mean BP is the single significant determining factors among age, sex, BP or heart rate in calibration error of the preceding week. The BP values became deviated small but significantly after 17 days of the calibration, with the change was on average 0.02 mmHg/daily. CONCLUSIONS: Smartwatch-based BP measurement is feasible for BP measurement every day. BP values showed large variability mostly according to measurement hours, then measurement days. The error during the calibration process showed substantial BP fluctuation, warranting meticulous calibration assisted by medical personnel.