# A Smartwatch or Just a Watch? A Validation Study of the Smartwatch KC08 for Measuring Blood Pressure

## TL;DR

This study tested a low-cost smartwatch for measuring blood pressure and found it unreliable for clinical use, except for heart rate.

## Contribution

The study validates the KC08 smartwatch's performance for cuffless BP and related measurements in a clinical setting.

## Key findings

- The KC08 smartwatch showed significant differences in BP, heart rate, and SpO2 compared to a reference device.
- The smartwatch had low variability and poor reliability for all outcomes except heart rate.
- Heart rate measurements showed no significant heteroscedasticity between the smartwatch and reference device.

## Abstract

(1) Background: The use of wearable cuffless devices has emerged as an out-of-office blood pressure (BP) monitor device to improve the management of hypertension. We aimed to validate a new, low-cost smartwatch for the measurement of BP and, secondarily, to assess its reliability for the measurement of blood oxygen saturation (SpO2) and heart rate. (2) Methods: We compared 1000 pairs of measurements (n = 100) acquired by a smartwatch (KC08) with those measured by a reference device. (3) Results: A total of 100 participants (41 ± 18 years) completed the measurements. The values for the systolic and diastolic BP, heart rate and SpO2 measured with the Smartwatch KC08 and the reference devices differed significantly (p < 0.05). In addition, the Smartwatch KC08 showed a low variability and poor reliability for all the assessed outcomes except for the heart rate. Moreover, no significant heteroscedasticity was observed for the heart rate measured by the Smartwatch KC08 and the reference sphygmomanometer. (4) Conclusions: The main findings of the present study suggest that the Smartwatch KC08 is not yet suitable for daily clinical practice, although it showed low intra-subject variability and reliability for the resting heart rate.