# Comparison of two validated oscillometric devices in a home-like setup reveals pronounced blood pressure differences and reduced precision

## TL;DR

This study found that wrist-based blood pressure devices can give higher and less consistent readings compared to upper-arm devices in a home-like setting.

## Contribution

The study reveals significant differences in accuracy and precision between two validated HBPM devices in non-clinical conditions.

## Key findings

- Wrist-derived blood pressure readings were higher than upper-arm measurements.
- Both devices showed increased bias and reduced precision with higher blood pressure levels.
- Hypertension classification had moderate agreement, with wrist devices over-diagnosing more often.

## Abstract

Home blood pressure monitoring (HBPM) is essential for long-term hypertension management, but its accuracy and reliability is questionable due to user inconsistencies and non-standard usage conditions. This study compared two validated HBPM devices – a wrist-based and a reference upper-arm monitor – in a home-like setup where participants placed the devices themselves. A total of 121 participants underwent four concurrent blood pressure (BP) measurements, with two taken in each arm, followed by a crossover of devices between arms after the initial two readings. Wrist-derived BP readings were higher than upper-arm measurements. With higher blood pressure levels, both devices exhibited greater bias, accompanied by reduced precision in systolic BP measurements. Additionally, hypertension classification showed only moderate agreement (Cohen’s kappa=0.58). The wrist monitor tended to over-diagnose hypertension and exhibited greater variability than the upper-arm device. These findings highlight the need for more guidance and education as well as critical evaluation of home blood pressure measurements provided by patients.