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Functional Regression Methods for Estimating 24-Hour Ambulatory Blood Pressure and Heart Rate Parameters in
Marta Karas1, Francesco Onorati1, Raul Torres1
1Takeda Development Center Americas, Inc., Cambridge, MA, USA.
Digital Biomarkers
|April 17, 2026
Summary
The 24-hour pattern method for estimating blood pressure (BP) and heart rate (HR) nocturnal dip is more reliable than fixed-window methods in narcolepsy type 1 (NT1) patients. This approach accurately assesses dipping patterns, even with sleep disturbances common in NT1.
Area of Science:
- Cardiology
- Neurology
- Sleep Medicine
Background:
- The nocturnal dip in blood pressure (BP) is a physiological process crucial for cardiovascular health.
- A "non-dipping" BP pattern (<10% reduction during sleep) is linked to increased cardiovascular disease risk.
- Narcolepsy type 1 (NT1) is associated with autonomic nervous system dysfunction, potentially affecting BP regulation during sleep.
Purpose of the Study:
- To compare different methods for estimating nocturnal BP and heart rate (HR) dip from ambulatory BP monitoring (ABPM) data in individuals with NT1.
- To evaluate the reliability of fixed-window, 24-hour pattern (cosinor model), and actigraphy-based methods for dip estimation in NT1.
- To determine the impact of sleep timing variability on dip classification in NT1 patients.
Main Methods:
- Utilized ABPM data from 31 participants with NT1 from a phase 2 clinical trial.
- Estimated sleep period time (SPT) using accelerometer data.
- Compared three dip estimation approaches: fixed-window, 24-hour pattern (two-component cosinor model), and actigraphy-based methods.
Main Results:
- The 24-hour pattern method showed higher correlations with actigraphy-based dip estimates compared to the fixed-window method for systolic BP (SBP), diastolic BP (DBP), and HR.
- Significant variability in SPT timing and duration was observed among participants.
- Classification of "non-dipper" status varied considerably based on the dip estimation method and BP type (SBP vs. DBP).
Conclusions:
- The 24-hour pattern approach using a cosinor model provides a robust and reliable method for assessing BP and HR nocturnal dip in NT1 patients.
- This method is particularly valuable for populations with disrupted sleep patterns, such as NT1, and does not necessitate concurrent actigraphy.
- Accurate dip estimation is critical, as classification methods significantly influence the identification of "non-dipper" status.
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