Evaluation of the ability of a commercially available cuffless wearable device to track blood pressure changes

Objectives: Cuffless wearable blood pressure (BP) devices may allow detailed evaluation of BP for prolonged periods, but their ability to accurately track BP changes is uncertain. We investigated whether a commercially available cuffless wearable device tracks: 24-h systolic (SBP) and diastolic BP (DBP) compared to conventional ambulatory monitoring (ABPM); and antihypertensive medication-induced BP changes compared to cuff-based home BP monitoring (HBPM). Methods: We fitted 41 participants (32% females, 58 +/- 14 years, 80% hypertensive) with a wrist-wearable cuffless BP device (Aktiia) continuously for 6-12 days. At the beginning and the end of this period, 24-h ABPM was performed. Three participants with hypertension (one female; 60 +/- 8 years) wore the Aktiia device and performed HBPM continuously one week before and 2 weeks after antihypertensive medication uptitration. Results: Compared to ABPM, Aktiia reported higher average SBP for 24-h (difference 4.9mmHg, 95% CI [1.9, 7.9]) and night-time (15.5[11.8, 19.1] mmHg; all P <= 0.01), but similar daytime (1.0 [- 1.8, 3.8] mmHg; P = 0.48). Similarly, average cuffless DBP was higher for 24-h (4.2 [2.3, 6.0] mmHg) and night-time (11.8 [9.5, 14.1] mmHg; both P< 0.001), but similar during daytime (1.4 [-0.4, 3.23] mmHg; P = 0.13). Aktiia also reported reduced night-time dip for SBP (difference 14.2 [12.1, 16.3] mmHg) and DBP (10.2 [8.5, 11.9] mmHg; both P< 0.001). The average medication-induced SBP/DBP decline after 2 weeks of uptitration was - 1.0/-0.8 mmHg with Aktiia vs. - 19.7/-11.5 mmHg with HBPM (P = 0.03 for difference). Conclusion: This cuffless wearable device did not accurately track night-time BP decline and results suggested it was unable to track medication-induced BP changes.