Association of Obstructive Sleep Apnoea Severity with Nocturnal Blood Pressure and Autonomic Dysfunction in Patients with Hypertension.

Objective

To determine the association of obstructive sleep apnoea (OSA) severity with nocturnal blood pressure patterns, blood pressure variability (BPV), and heart rate variability (HRV) in patients with hypertension. STUDY

Design

An observational study. Place and Duration of the Study: Cardiac Function Laboratory, Department of Cardiology, Xianning Central Hospital, the First Affiliated Hospital of Hubei University of Science and Technology, Xianming, China, from January 2024 to May 2025. METHODOLOGY Adult hypertensive patients who underwent polysomnography (PSG) were analysed. OSA severity was defined by the apnoea-hypopnoea index (AHI). Available ambulatory blood pressure monitoring (ABPM) and Holter data were used to assess nocturnal systolic blood pressure (SBP) fall, non-dipping, BPV, and HRV. Group comparisons were performed using the Kruskal-Wallis test, the chi-square test, or Fisher's exact test, as appropriate. Spearman's correlation and regression analyses were performed where appropriate.

Results

Eighty-six patients comprised the PSG cohort; 44 had ABPM data, and 60 had HRV data. Body mass index differed across OSA severity categories (severe OSA: 30.00 [27.92-33.60] kg/m2; p = 0.001). In the ABPM+PSG sub-cohort, nocturnal SBP fall showed a decreasing trend with increasing OSA severity (severe OSA: 2.43 [-1.89 to 7.68%]; p = 0.105). For every 10 events/hour increase in the AHI, nocturnal SBP increased after adjustment (β = 3.63, 95% CI 0.42-6.83; p = 0.032).

Conclusion

Greater OSA severity was associated with higher nocturnal SBP and possible autonomic imbalance. ABPM with OSA screening may help identify high-risk nocturnal blood pressure phenotypes in hypertensive patients. KEY WORDS Obstructive sleep apnoea, Hypertension, Ambulatory blood pressure monitoring, Circadian rhythm, Blood pressure variability, Heart rate variability.