Nocturnal Blood Pressure Dipping in Adults: A Comparison Between Cuffless and Ambulatory Blood Pressure Monitoring

Cuffless blood pressure (BP) devices have demonstrated potential in estimating daytime BP but have not been able to predict nocturnal BP precisely, creating difficulties when the intended use is ambulatory BP monitoring (ABPM). We evaluated the ability of a photoplethysmography-based cuffless BP device, with the intended use 24-hour ABPM, to estimate nocturnal BP compared to a cuff-based oscillometric device.

Participants underwent 24-hour ABPM with the cuffless device placed on the non-dominant upper arm and a validated cuff-based oscillometric device on the dominant arm. The difference between mean awake and asleep BP (awake-asleep BP change) was calculated for both devices and used in the analyses. The statistical analyses were guided by the Awake/Asleep test (European Society of Hypertension 2023 Recommendations), however, there were methodological deviances from these recommendations. Most importantly, we used only cuffless BP values that were obtained simultaneously with the reference device.

Data from 50 participants, aged 18-80 years, with mean (standard deviation; SD) inclusion office systolic/diastolic BP (SBP/DBP) 120.1 (11.5)/75.3 (7.9), were analyzed. The cuffless device achieved a mean difference [95% limits of agreement] of 1.6 [-8.0, 11.2] mmHg for SBP and 1.2 [-6.7, 9.1] mmHg for DBP in awake-asleep BP changes compared to the reference. Pearson correlation coefficients (95% confidence interval) for SBP/DBP were 0.75 (0.59, 0.85)/0.74 (0.58, 0.84). Our population had an overrepresentation of normal and low BP.

Although the cuffless device shows promise in successfully tracking nocturnal BP, full validation is required before clinical use.