Obstructive sleep apnea phenotypes in men based on characteristics of respiratory events during polysomnography
The upper airway (UA) anatomical collapsibility, UA muscle responsiveness, breathing control, and/or arousability are important contributing factors for obstructive sleep apnea (OSA). Differences in clinical manifestations of OSA are believed to reflect interactions among these factors. We aimed to classify OSA patients into subgroups based on polysomnographic (PSG) variables using cluster analysis and assess each subgroup’s characteristics.
Men with moderate or severe OSA and without any concomitant heart or psychosomatic disease were recruited. A hierarchical cluster analysis was performed using variables including fraction of apnea, respiratory event duration, minimum oxygen saturation, arousal rate before termination, and frequency of respiratory events in the supine position. The impact of sleep stages or body position on PSG variables was also evaluated in each cluster.
A total of 210 men (mean age, 50.0 years, mean body mass index, 27.4 kg/m2) were studied. The three subgroups that emerged from the analysis were defined as follows: cluster 1 (high fraction of apnea and severe desaturation (20%)), cluster 2 (high fraction of apnea and long event duration (31%)), and cluster 3 (low fraction of apnea (49%)). There were differences in the body mass index and apnea type between the three clusters. Sleep stages and/or body position affected PSG variables in each cluster.
Patients with OSA could be divided into three distinct subgroups based on PSG variables. This clustering may be used for assessing the pathophysiology of OSA to tailor individual treatment other than continuous positive airway pressure therapy.
KeywordsSleep apnea Apnea-hypopnea index Polysomnography Respiratory events Arousals
Body mass index
Fraction of apnea
Obstructive sleep apnea
Ratio of arousal
Distance from sella to nasion
Saturation of oxygen
The authors thank Youichiro Takei, RPSGT, for his help with data collection and Editage (www.editage.jp) for English language editing.
This study is partly supported by the Japan Society for the Promotion of Science (grant numbers 15K11463, 26507011, and 15H05301). The sponsor had no role in the design of the study, the collection and analysis of the data, or the preparation of the manuscript.
HN, MK, ST, and YI contributed to the study design; HN, MK, and MY contributed in data acquisition; HN, ST, and YI analyzed data; and HN, MK, ST, and YI prepared the manuscript.
Compliance with ethical standards
Conflict of interest
YI consults for Takeda Pharmaceutical Co., MSD and Eisai Co. and has received grant/research support from Astellas Pharma, Otsuka Pharmaceutical Co., Pacific Medico, and Philips Respironics. All other authors have no conflicts of interest to disclose.
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