Apnea-hypopnea index is correlated with pulse rate in patients with sleep-related breathing disorder without hypertension, cardiovascular disease, or diabetes mellitus
Seung-Gul Kang 8*, Jeonggeun Moon 1, Jae Hyoung Park 2, Seo-Eun Cho 3, Jae Kean Ryu 7, Kwang-Pil Ko 4, Seung-Heon Shin 5, Ji-Eun Kim 6
1Division of Cardiology, Department of Internal Medicine, Gil Medical Center, Gachon University College of Medicine, 2Department of Cardiology, Cardiovascular Center, Korea University Anam Hospital, 3Department of Psychiatry, Gil Medical Center, Gachon University College of Medicine, 4Department of Preventive Medicine, Gachon University College of Medicine, 5Department of Otorhinolaryngology, School of Medicine, Catholic University of Daegu, 6Department of Neurology, School of Medicine, Catholic University of Daegu, 7Division of Cardiology, Department of Internal Medicine, School of Medicine, 8Department of Psychiatry and Sleep Medicine Center, Gil Medical Center, Gachon University College of Medicine
Received: December 10, 2020; Revised: January 28, 2021; Accepted: February 23, 2021; Published online: February 23, 2021.
© The Korean College of Neuropsychopharmacology. All rights reserved.

Background: This study aimed to compare the mean pulse rate (PR) and mean blood pressure (BP) between patients with obstructive sleep apnea (OSA) and those with simple snoring (SS) during a 24-hour period, and to investigate the correlation between apnea-hypopnea index (AHI), PR, and BP in sleep-related breathing disorder (SRBD) patients with and without hypertension, diabetes mellitus (DM), and cardiovascular diseases (CVDs).
Materials and methods: Ninety SRBD patients underwent full-night polysomnography, and ambulatory BP and PR were monitored for 24 hours. Participants were classified into OSA (AHI≥5) and control (SS) (AHI<5) groups, and BP and PR were compared. Participants were also divided into groups with and without hypertension, CVDs, or DM to analyze the correlation between AHI, BP, and PR in each group.
Results: Mean PRs during the daytime period and during the whole 24-hour period in the OSA group were significantly higher than those in the SS group after controlling for potential confounders. No significant difference was observed in mean BP between the groups. Partial correlation analysis after controlling for confounders showed significant correlation between AHI and PR during daytime and the 24-hour period in participants without hypertension, DM, or CVDs, but not in participants with these conditions.
Conclusion: The significant differences and correlations only in PR (not in BP) found in this study suggest that PR could be an early marker for SRBD in individuals without comorbidities, and that an increased sympathetic tone could be responsible for future occurrence of CVD.
Keywords: apnea-hypopnea index, obstructive sleep apnea, sleep-related breathing disorders, polysomnography, pulse rate, 24-hour ambulatory blood pressure test