Modeling 24-Hour Blood Pressure Rhythms Using Mixed-Effects Cosinor Models.

Area of Science:

• Chronobiology
• Pediatric Sleep Medicine
• Cardiovascular Physiology

Background:

• Circadian rhythm analysis of 24-hour ambulatory blood pressure (BP) typically uses single-component cosinor models.
• These traditional models are limited in capturing complex or asymmetric circadian patterns in blood pressure.
• Obstructive sleep apnea (OSA) is a condition that may affect circadian regulation of cardiovascular parameters.

Purpose of the Study:

• To evaluate and compare four mixed-effects cosinor models for analyzing circadian patterns in pediatric blood pressure.
• To assess differences in circadian BP parameters between children with and without obstructive sleep apnea (OSA).
• To determine if multi-component models offer superior insight into OSA-related circadian BP alterations.

Main Methods:

• Applied 1- to 4-component mixed-effects cosinor models to 24-h ambulatory BP data from 219 children (controls and OSA groups).
• Analyzed systolic (SBP) and diastolic (DBP) blood pressure data, estimating parameters like MESOR, amplitude, and acrophase.
• Compared circadian parameter estimations between non-OSA, mild OSA, and moderate-to-severe OSA (MS-OSA) groups.

Main Results:

• The 3-component mixed-effects cosinor model demonstrated the best fit for both SBP and DBP data.
• Children with MS-OSA exhibited a higher DBP MESOR compared to controls.
• OSA was associated with a dampened early afternoon BP peak and an increased late-evening BP peak, with timing shifts observed in SBP and DBP.

Conclusions:

• Multi-component mixed-effects cosinor models provide a more accurate fit for pediatric 24-h BP rhythms than single-component models.
• These advanced models successfully identified significant circadian BP pattern differences in children with OSA.
• The findings highlight the utility of sophisticated cosinor models in understanding cardiovascular dysregulation associated with pediatric OSA.