Validation of a popular consumer-grade cuffless blood pressure device for continuous 24 h monitoring.

Aims: Hypertension is a leading cause of death worldwide, yet many hypertensive cases remain undiagnosed. Wearable, cuffless blood pressure (BP) monitors could be deployed at scale, but their accuracy remains undetermined. Methods and results: This study validated a popular consumer-grade wearable BP monitor (W-BPM, Aktiia), using a medical-grade ambulatory device (A-BPM, Mobil-O-Graph), for reference. Thirty-one participants (aged 19-62 years, 17 (55%) females, in office BP 121 ± 15 over 77 ± 12 mmHg) simultaneously wore both devices for 24 h. Systolic BP (SBP), diastolic BP (DBP), and heart rate (HR) were measured in pre-set intervals by the A-BPM and at rest by the W-BPM. Agreement was assessed using standard methods. Accuracy in identifying high BP (mean 24 h SBP/DBP > 130/80 mmHg) was assessed. Compared to A-BMP, mean SBP and DBP tended to be slightly lower during the day and not significantly different at night. Nocturnal BP dipping and BP variability were significantly underestimated by the W-BPM. Agreement between the two devices was poor to moderate (limits of agreement of about -30/+30 mmHg for SBP and -20/+15 mmHg for DBP, correlation coefficients between 0.20 and 0.42). Sensitivity and specificity for high BP detection were around 50% and 80%, respectively. Limiting the analysis to measures taken in similar conditions (within 10 min and with HR within ±10 b.p.m.) did not improve agreement. Conclusion: Low agreement suggests that the cuffless device may not be a suitable replacement for standard 24 h cuff-based ambulatory monitoring. Further data are required to assess the clinical role of cuffless BP monitors.