减重代谢手术患者腹部脂肪分布与阻塞性睡眠呼吸暂停的相关性研究

目的 分析腹部磁共振(MR)图像中腰1-腰2(L1-L2)层面腹腔内脏脂肪(VAT)、腹腔皮下脂肪(SAT)含量及体质量指数(BMI)与阻塞性睡眠呼吸暂停(OSA)的发生及严重程度之间的关系.方法 选取2017年11月至2019年11月于首都医科大学附属北京友谊医院治疗的代谢综合征患者的临床资料,收集BMI、多导睡眠检...     

Estimated respiratory arousal threshold in patients with rapid eye movement obstructive sleep apnea

Purpose

Rapid eye movement (REM) obstructive sleep apnea (OSA) is a prevalent clinical phenotype. However, the literature focusing on the pathophysiology of REM OSA is limited. This study compared the proportion of individuals with a low respiratory arousal threshold between patients with REM and non-REM OSA.

Methods

REM OSA was defined as having an apnea–hypopnea index (AHI)?≥?5 and AHI during REM (AHI-REM)/AHI during NREM (AHI-NREM)?≥?2. REM OSA was sub-divided into REM-predominant OSA and REM-isolated OSA. REM-predominant OSA was defined as satisfying the definition of REM OSA and having an AHI-NREM?≥?5. REM-isolated OSA was defined as satisfying the definition of REM OSA and having an AHI-NREM?<?5. Patients with an AHI-REM/AHI-NREM?<?2 were defined as having non-REM OSA. A low respiratory arousal threshold was defined as having 2 or more of the following conditions: AHI?<?30 events/h, proportion of hypopnea?>?58.3%, and nadir SpO₂?>?82.5%.

Results

The proportions of individuals with low respiratory arousal thresholds among individuals with REM-predominant OSA and REM-isolated OSA were significantly higher (77.2% and 93.7%, respectively) than that of patients with non-REM OSA (48.6%). This was also true when the analysis was performed according to sex.

Conclusion

These results indicate that a low respiratory arousal threshold might be an important endotype that contributes to the pathogenesis of REM OSA, especially in REM-isolated OSA.

     

Gender differences in the polysomnographic features of obstructive sleep apnea

We examined the influence of gender on the polysomnographic features of obstructive sleep apnea (OSA) in a retrospective study of 830 patients with OSA diagnosed by overnight polysomnography (PSG). The severity of OSA was determined from the apnea- hypopnea index (AHI) for total sleep time (AHI(TST)), and was classified as mild (5 to 25 events/h), moderate (26 to 50 events/h), and severe (> 50/events/h). Differences in OSA during different stages of sleep were assessed by comparing the AHI during non-rapid eye movement (NREM) (AHI(NREM)) and rapid eye movement (REM) (AHI(REM)) sleep and calculating the "REM difference" (AHI(REM) - AHI(NREM)). Additionally, each overnight polysomnographic study was classified as showing one of three mutually exclusive types of OSA: (1) mild OSA, which occurred predominantly during REM sleep (REM OSA); (2) OSA of any severity, which occurred predominantly in the supine position (S OSA); or (3) OSA without a predominance in a single sleep stage or body position (A OSA). The mean AHI(TST) for men was significantly higher than that for women (31.8 +/- 1.0 versus 20.2 +/- 1.5 events/h, p < 0. 001). The male-to-female ratio was 3.2:1 for all OSA patients, and increased from 2.2:1 for patients with mild OSA to 7.9:1 for those with severe OSA. Women had a lower AHI(NREM) than did men (14.6 +/- 1.6 versus 29.6 +/- 1.1 events/h, p < 0.001), but had a similar AHI(REM) (42.7 +/- 1.6 versus 39.9 +/- 1.2 events/h). Women had a significantly higher REM difference than did men (28.1 +/- 1.5 versus 10.3 +/- 1.1 events/h, p < 0.01). REM OSA occurred in 62% of women and 24% of men with OSA. S OSA occurred almost exclusively in men. We conclude that: (1) OSA is less severe in women because of milder OSA during NREM sleep; (2) women have a greater clustering of respiratory events during REM sleep than do men; (3) REM OSA is disproportionately more common in women than in men; and (4) S OSA is disproportionately more common in men than in women. These findings may reflect differences between the sexes in upper airway function during sleep in patients with OSA.     

Comparison of cardiac structural and functional changes in obese otherwise healthy adults with versus without obstructive sleep apnea

Obstructive sleep apnea (OSA) and obesity have been linked to systolic and diastolic dysfunction of the left ventricle. Right ventricular function is poorly understood in the 2 clinical conditions. Data from this study show that otherwise healthy obese patients with OSA had increased an left atrial volume index compared with similarly obese patients without OSA (16.3 +/- 1.2 ml/m in obese patients without OSA vs 20.2 +/- 1.0 ml/m in those with OSA, p = 0.02) and altered diastolic function reflected by changes in mitral annular late diastolic velocity (-5.7 +/- 0.7 cm/s in obese patients without OSA vs -7.3 +/- 0.7 cm/s in those with OSA, p = 0.007), mitral annular early diastolic velocity (-7.9 +/- 0.6 cm/s in obese patients without OSA vs -6.4 +/- 0.3 cm/s in those with OSA, p = 0.05), and early to late diastolic annular ratio >1 (82% of obese patients without OSA vs 26% of those with OSA, p = 0.001), which may be signs of early subclinical impairment of cardiac function. Importantly, healthy obese subjects had similarly increased left ventricular mass compared with obese patients with OSA but normal diastolic function and left atrial size. There was a trend toward abnormal right ventricular filling in patients with OSA, measured by altered superior vena cava diastolic velocity during expiration (-15 +/- 2 cm/s in obese patients without OSA vs -10 +/- 3 cm/s in those with OSA, p = 0.2) and a tendency toward diastolic dysfunction reflected by decreased lateral tricuspid annular early diastolic velocity (-7.2 +/- 0.5 cm/s in obese patients without OSA vs -6.1 +/- 0.5 cm/s in those with OSA, p = 0.1) beyond that seen in obesity alone. In conclusion, OSA independent of obesity may induce cardiac changes that could predispose to atrial fibrillation and heart failure.     

Primary aldosteronism and obstructive sleep apnea: A single-center cross-sectional study of the Japanese population

A recent report demonstrated that the prevalence of obstructive sleep apnea (OSA) is 67.6% among Caucasian and Chinese patients with primary aldosteronism (PA). Moreover, the report showed a significant association between plasma aldosterone concentration (PAC) and the severity of OSA in Caucasian patients. However, no studies have examined the prevalence of OSA with PA or the association of its severity with PAC in the Japanese population. We retrospectively evaluated the prevalence and severity of OSA in 71 newly diagnosed Japanese patients with PA. Thirty-nine (55%) of the 71 patients were diagnosed with OSA, and 69% of PA patients with OSA reported snoring. No correlation was found between the respiratory event index (REI), snoring index, and PAC and plasma renin activity (PRA). In contrast, REI correlated significantly with body mass index (BMI), which was significantly correlated with PRA. In conclusion, although the severity of OSA did not correlate with PAC and PRA, there was a high prevalence of OSA among Japanese patients with PA. Moreover, the severity of OSA was strongly affected by BMI. Thus, the examination of OSA in patients with PA and the proper management of OSA might be important for the Japanese population.     

Prevalence of left ventricular hypertrophy in persons with and without obstructive sleep apnea

We investigated the prevalence of left ventricular hypertrophy (LVH) in persons with and without obstructive sleep apnea (OSA). Fifty-three persons had a nocturnal polysomnogram to diagnose OSA and 2-dimensional echocardiograms to measure left ventricular mass. OSA was considered mild if the respiratory disturbance index (RDI) was 5 to 15, moderate if the RDI was 15 to 30, and severe if the RDI was >30. LVH was diagnosed if the left ventricular mass index was >110 g/m in women and >134 g/m in men. LVH was present in 21 of 27 persons (78%) with moderate or severe OSA, in 6 of 13 persons (46%) with mild OSA, and in 3 of 13 persons (23%) with no OSA (P < 0.001 comparing moderate or severe OSA with no OSA and P < 0.05 comparing moderate or severe OSA with mild OSA). OSA was a significant independent predictor of LVH after controlling the confounding effects of hypertension with an odds ratio of 3.579 (95% confidence interval, 1.589-8.058).     

Atrial fibrillation in obstructive sleep apnea

Atrial fibrillation(AF) is a common arrhythmia with rising incidence.Obstructive sleep apnea(OSA) is prevalent among patients with AF.This observation has prompted significant research in understanding the relationship between OSA and AF.Multiple studies support a role of OSA in the initiation and progression of AF.This association has been independent of obesity,body mass index and hypertension.Instability of autonomic tone and wide swings in intrathoracic pressure are seen in OSA.These have been mechanistically linked to initiation of AF in OSA patients by lowering atrial effective refractory period,promoting pulmonary vein discharges and atrial dilation.OSA not only promotes initiation of AF but also makes management of AF difficult.Drug therapy and electrical cardioversion for AF are less successful in presence of OSA.There has been higher rate of early and overall recurrence after catheter ablation of AF in patients with OSA.Treatment of OSA with continuous positive airway pressure has been shown to improve control of AF.However,additional studies are needed to establish a stronger relationship between OSA treatment and success ofAF therapies.There should be heightened suspicion of OSA in patients with AF.There is a need for guidelines to screen for OSA as a part of AF management.     

Clinical manifestations of sleep apnea

Obstructive sleep apnea (OSA) may manifest in a number of ways from subtle intrusion into daily life to profound sleepiness, snoring, witnessed apneas and other classic symptoms. Although there is increasing evidence suggesting OSA can adversely affect health in a variety of ways, this disorder remains underdiagnosed. The most well-escribed health consequences of OSA relate to the cardiovascular system. Hypertension and arrhythmias have a strong association with OSA, and evidence suggests that treatment of OSA in patients with refractory hypertension and in patients planning cardioversion for atrial fibrillation may be of particularly importance. Significant associations between heart failure and OSA as well as complex sleep apnea have also been well-described. Cerebrovascular insult, impaired neurocognition, and poorly controlled mood disorder are also associated with in OSA. Therapy for OSA may ameliorate atherosclerotic progression and improve outcomes post-cerebrovascular accident (CVA). OSA should be considered in patients complaining of poor concentration at work, actual or near-miss motor vehicle accidents, and patients with severe sleepiness as a component of their co-morbid mood disorders. The metabolic impact of OSA has also been studied, particularly in relation to glucose homeostasis. Also of interest is the potential impact OSA has on lipid metabolism. The adverse effect untreated OSA has on glucose tolerance and lipid levels has led to the suggestion that OSA is yet another constituent of the metabolic syndrome. Some of these metabolic derangements may be related to the adverse effects untreated OSA has on hepatic health. The cardiovascular, neurocognitive, and metabolic manifestations of OSA can have a significant impact on patient health and quality of life. In many instances, evidence exists that therapy not only improves outcomes in general, but also modifies the severity of co-morbid disease. To mitigate the long-term sequela of this disease, providers should be aware of the subtle manifestations of OSA and order appropriate testing as necessary.     

Dynamic changes in EEG spectra during obstructive apnea in children

Children are less likely to demonstrate EEG arousal during obstructive sleep apnea (OSA) than adults. We hypothesized that changes in spectral EEG characteristics occur during REM-associated OSA in the absence of arousal. Eight snoring children underwent overnight polysomnography. OSA events during REM periods not associated with EEG or behavioral arousal were identified. EEG signals from C3A2 and C4A1 leads corresponding to 1) < or =10-sec epochs preceding OSA (PRE), 2) the obstructed period (OSA), and 3) < or =10-sec epochs following airflow resumption (POST) were subjected to fast Fourier transform (FFT) routines. Seventy-two isolated OSA, and 14 clusters of > 4 OSA events were analyzed. In single OSA, delta OSA amplitude was lower than in PRE (P < 0.01) and in POST (P < 0.001). Furthermore, POST delta amplitude was higher than PRE (P < 0.01). In contrast, in OSA clusters, the dynamic differences in delta amplitude disappeared after the second OSA. Reciprocal increases and decreases occurred for the theta frequency domain during OSA and post-OSA, while sigma and beta frequency power did not change. We conclude that during isolated OSA episodes without arousal, significant decreases in power selectively occur for delta frequency, and are followed by a rebound increase upon termination of apnea. The delta changes are progressively attenuated during repeated OSA. We postulate that delta changes may reflect ongoing adaptations in sleep pressure which are necessary to relieve the respiratory compromise, and may represent subtle evidence for arousal and consequent sleep fragmentation in children with OSAS.     

Obstructive sleep apnea related to rapid-eye-movement or non-rapid-eye-movement sleep: comparison of demographic,anthropometric, and polysomnographic features

Objective

: To determine whether there are significant differences between rapid-eye-movement (REM)-related obstructive sleep apnea (OSA) and non-REM (NREM)-related OSA, in terms of the demographic, anthropometric, and polysomnographic characteristics of the subjects.

Methods

: This was a retrospective study of 110 patients (75 males) with either REM-related OSA (n = 58) or NREM-related OSA (n = 52). To define REM-related and NREM-related OSA, we used a previously established criterion, based on the apnea-hypopnea index (AHI): AHI-REM/AHI-NREM ratio > 2 and ≤ 2, respectively.

Results

: The mean age of the patients with REM-related OSA was 49.5 ± 11.9 years, whereas that of the patients with NREM-related OSA was 49.2 ± 12.6 years. The overall mean AHI (all sleep stages combined) was significantly higher in the NREM-related OSA group than in the REM-related OSA group (38.6 ± 28.2 vs. 14.8 ± 9.2; p < 0.05). The mean AHI in the supine position (s-AHI) was also significantly higher in the NREM-related OSA group than in the REM-related OSA group (49.0 ± 34.3 vs. 18.8 ± 14.9; p < 0.0001). In the NREM-related OSA group, the s-AHI was higher among the men. In both groups, oxygen desaturation was more severe among the women. We found that REM-related OSA was more common among the patients with mild-to-moderate OSA, whereas NREM-related OSA was more common among those with severe OSA.

Conclusions

: We found that the severity of NREM-related OSA was associated mainly with s-AHI. Our findings suggest that the s-AHI has a more significant effect on the severity of OSA than does the AHI-REM. When interpreting OSA severity and choosing among treatment modalities, physicians should take into consideration the sleep stage and the sleep posture.     

Effects of obstructive sleep apnea and its treatment on cardiovascular risk in CAD patients

This study, in optimally treated CAD patients with newly diagnosed OSA, focused on (1) The relationships between OSA and serum biomarkers of four potential pathways of cardiovascular injury in OSA: high-sensitivity C-reactive protein (hs-CRP), endothelin-1 (ET-1), N terminal pro B type natriuretic peptide (NT-proBNP) and fibrinogen; and (2) The effect of continuous positive airway pressure (CPAP) therapy on these markers. 151 Chinese patients with proven CAD and standard medication were enrolled. After polysomnography, patients were classified into four groups according to apnea-hypopnea index (AHI): no OSA (n?=?25); mild OSA (n?=?50); moderate OSA (n?=?43); severe OSA (n?=?33). Morning levels of hs-CRP, ET-1, NT-proBNP and fibrinogen were assayed and repeated in severe OSA patients after 3-months CPAP treatment. Hs-CRP was greater in patients with severe OSA than those with no OSA or mild OSA (P?=?0.001, P?=?0.003; respectively). After adjustment for confounders, the hs-CRP levels correlated most strongly with AHI and oxygen desturation index (ODI) (r?=?0.439, P?相似文献   

Obstructive sleep apnea and metabolic dysfunction in polycystic ovary syndrome

Obstructive sleep apnea (OSA) is an underrecognized, yet significant factor in the pathogenesis of metabolic derangements in polycystic ovary syndrome (PCOS). Recent findings suggest that there may be two "subtypes" of PCOS, i.e. PCOS with or without OSA, and these two subtypes may be associated with distinct metabolic and endocrine alterations. PCOS women with OSA may be at much higher risk for diabetes and cardiovascular disease than PCOS women without OSA and may benefit from therapeutic interventions targeted to decrease the severity of OSA. The present chapter will review what is currently known about the roles of sex steroids and adiposity in the pathogenesis of OSA, briefly review the metabolic consequences of OSA as well as the metabolic abnormalities associated with PCOS, review the prevalence of OSA in PCOS and finally present early findings regarding the impact of treatment of OSA on metabolic measures in PCOS.     

老年阻塞性睡眠呼吸暂停患者的颈动脉内膜中层厚度

目的观察老年阻塞性睡眠呼吸暂停（OSA）患者颈动脉内膜中层厚度（IMT）,探讨OSA与动脉粥样硬化标志物之间的关系。方法将住院的老年患者79例经多导睡眠呼吸仪行睡眠监测分为4组：对照组、轻度、中度、重度OSA,同时采用HDI彩色多普勒超声显像仪检查IMT,取左右两侧的均值。结果平均IMT与OSA严重程度、睡眠呼吸暂停低通气指数成正相关,与最低氧饱和度成负相关,差异具有统计学意义（P〈0.05）。校正年龄、体质量指数（BMI）、低密度脂蛋白胆固醇、降脂药应用等动脉硬化的危险因素后,平均IMT和睡眠程度的相关系数为r=0.578（P〈0.01）。OSA严重程度与BMI是颈动脉内膜中层增厚的独立危险因素。结论在老年OSA患者中,OSA严重程度和BMI在颈动脉粥样硬化的进程中可能发挥重要作用。     

Impact of obstructive sleep apnea on blood pressure and cardiovascular risk factors in Japanese men: A cross-sectional study in work-site group

It has been shown that obstructive sleep apnea (OSA) is related to hypertension and cardiovascular disease; however, the prevalence of OSA in general population and the impact of it on blood pressure especially in Japan has not been well determined. We have conducted a screening test for OSA from 2003 to 2011. In addition, a cross-sectional analysis was performed in 2012 to determine the association of OSA and cardiovascular risk factors in Japanese men (18–69 years of age; mean age, 44.4 ± 0.2). The study group consisted of 2208 male employees, and OSA was evaluated by using the 4% oxygen desaturation index and apnea-hypopnea index (AHI). The prevalence of mild-to-moderate (5≤AHI<30) and severe (AHI≥30) OSA in the studied subjects were 7.1%, and 6.1%, respectively. Among the 135 severe OSA subjects, 105 (77.8%) had been treated with continuous positive airway pressure. Both systolic and diastolic blood pressures (DBP) were significantly increased in the subjects with severe OSA compared with those without OSA. These associations in DBP remained observed after adjustment for age, body mass index (BMI), estimated glomerular filtration rate, HbA_1c, current alcohol intake, current smoking habits, and OSA treatment. DBP in severe OSA subjects were significantly increased in 1807 subjects who were not treated for hypertension or OSA. However, the levels of blood pressures were not decreased by OSA treatment. These results suggest that the prevalence of OSA is relatively high in middle-aged Japanese men and that blood pressures were elevated in the subjects with severe OSA.     

Causes and consequences of blood pressure alterations in obstructive sleep apnea

The obstructive sleep apnea (OSA) syndrome has been considered to be a cause of both transient blood pressure elevations during sleep and sustained hypertension during the awake state. The purpose of this review was to examine critically the existing literature regarding (1) the blood pressure alterations associated with OSA, (2) causal mechanisms relating specific blood pressure alterations to OSA, and (3) potential consequences of the systemic circulatory abnormalities associated with OSA. Particular attention was directed at studies that assessed the prevalence of OSA in patients with hypertension and that examined the effects on blood pressure of treatment of OSA. We conclude that patients with OSA have abnormal sleep blood pressure patterns, manifested most frequently by apnea-associated blood pressure elevations. Confounding factors such as obesity and antihypertensive drug therapy, and conflicting evidence regarding changes in daytime blood pressure after therapy for OSA, make it premature to conclude that OSA and daytime hypertension are directly associated. Circumstantial evidence suggests that the blood pressure alterations that occur during sleep could contribute to the high cardiovascular morbidity in patients with OSA. Further research into the relationship between OSA and hypertension should improve the future care of patients with these conditions and enhance our understanding of cardiopulmonary pathophysiology.     

阻塞性睡眠呼吸暂停对2型糖尿病患者C肽水平的影响

目的 评价未经治疗的阻塞性睡眠呼吸暂停(OSA)对2型糖尿病患者反映胰岛功能的指标C肽的影响.方法 60例2型糖尿病患者行多导睡眠图(PSG)检查,并抽血检测C肽.根据呼吸暂停-低通气指数(AHI)将受试者分为4组:无OSA组(AHI＜5)20例;轻度OSA组(5≤AHI＜15)21例;中度OSA组(15≤AHI＜30...     

Cephalometric assessment of craniofacial morphology in Chinese patients with obstructive sleep apnoea

OBJECTIVE: To compare the differences in craniofacial morphology in Chinese patients with and without obstructive sleep apnoea (OSA). METHOD: We performed lateral cephalometric radiographs on 94 consecutive patients (77 males) referred with snoring or other symptoms suggestive of OSA for polysomnography (PSG). Significant OSA was defined as an apneoa-hypopnoea index (AHI) > or = 10/h of sleep on overnight PSG. The cephalometric data were compared between those with and without significant OSA. RESULTS: (mean +/- SD) There were 69 (56 males) with significant OSA with mean age 53 +/- 12 years, body mass index (BMI) 28.6 +/- 5.0 kg/m2, AHI 36.5 +/- 20.6/h, and minimum SaO2 76 +/- 14%. There were 25 controls (21 males) without significant OSA with similar age and BMI. The mandibular plane to hyoid bone distance (MPH) and the perpendicular distance from hyoid bone to the line connecting C3 vertebra and retrognathion (HHI) were significantly longer in the OSA patients. The angle measurement from sella to nasion to point A (SNA) was smaller in the OSA group. MPH distance was the only independent variable for significant OSA with an odds ratio of 3.47 (95% CI 1.39-8.66). Abnormalities of the MPH and SNA were more marked in the OSA patients with BMI > or = 30 kg/m2. CONCLUSIONS: Significant differences in craniofacial morphology are noted between OSA patients and non-apnoeic controls. An inferiorly positioned hyoid bone and a retropositioned maxilla may predispose obese patients to more severe OSA.     

阻塞性睡眠呼吸暂停群与血压的实时研究

目的　观察阻塞性睡眠呼吸暂停 (OSA)患者OSA连续发生 (OSA群 )时的实时血压改变 ,确定OSA群对血压的影响。方法　全部病例年龄均在 6 0岁以下 ,未服用过任何降血压药物治疗。以多导睡眠图 (PSG)检测睡眠过程的呼吸事件 ,同时以PWTT法连续测量血压。确诊为OSA组病人 ,在连续出现OSA群时 ,对血压作 2 0次等时取样 ,并与经PSG检查排除OSA的对照组病人比较 ,确定OSA群发生时的血压改变情况。结果　 92 %的OSA患者在OSA群发生时均有明显的血压升高 ,平均收缩压升高 5 8mmHg,舒张压升高 3 7mmHg ,最高收缩压升高 18 7mmHg ,舒张压升高12mmHg,明显高于非OSA病人 (P <0 0 1)。结论　考虑到其他影响因素 ,仍可认为 ,OSA(特别是连续发生的OSA群 ) ,与血压升高有直接关系 ,血压升高的程度、持续时间与OSA的严重程度正相关     

Obstructive sleep apnea and its relationship to cardiac arrhythmias

Obstructive sleep apnea (OSA) affects approximately 4% of middle-aged men and 2% of middle-aged women. Cardiac arrhythmias are common problems in patients with OSA, even though the true prevalence and clinical relevance of cardiac arrhythmias remains to be determined. The presence and complexity of both tachyarrhythmias and bradyarrhythmias may influence morbidity, mortality, and the quality of life for OSA patients. Although the exact mechanisms underlying the link between OSA and cardiac arrhythmias are not well established, they could be partially the same proposed mechanisms relating OSA to different cardiovascular diseases. OSA is characterized by repetitive pharyngeal collapse during sleep that leads to markedly reduced or absent airflow, followed by oxyhemoglobin desaturation, persistent inspiratory efforts against an occluded airway, and termination by arousal from sleep. These mechanisms elicit a variety of autonomic, hemodynamic, humoral, and neuroendocrine responses that by themselves evoke acute and chronic changes in cardiovascular function. These effects may lead to the development of cardiac arrhythmias and any other form of cardiovascular disease linked to OSA. The aims of this review are to describe the essential cardiovascular pathophysiological aspects of OSA, to outline the relationship between OSA and both tachyarrhythmias and bradyarrhythmias and their possible influence in the natural history of OSA patients, and to assess the effects of OSA treatment on the presence of cardiac arrhythmias.     

Phenotypes of patients with mild to moderate obstructive sleep apnoea as confirmed by cluster analysis

Background and objective: Patients with OSA manifest different patterns of disease. However, this heterogeneity is more evident in patients with mild‐moderate OSA than in those with severe disease and a high total AHI. We hypothesized that mild‐moderate OSA can be categorized into discreet disease phenotypes, and the aim of this study was to comprehensively describe the pattern of OSA phenotypes through the use of cluster analysis techniques. Methods: The data for 1184 consecutive patients, collected over 24 months, was analysed. Patients with a total AHI of 5–30/h were categorized according to the sleep stage and position in which they were predominantly affected. This categorization was compared with one in which patients were grouped using a K‐means clustering technique with log linear modelling and cross‐tabulation. Results: Patients with mild‐moderate OSA can be categorized according to polysomnographic parameters. This clinical categorization was validated by comparison with a categorization in which patients were grouped by unsupervised K‐means cluster analysis. The clinical groups identified were: (i) rapid eye movement (REM) predominant OSA, 44.6%; (ii) non‐REM predominant OSA, 18.9%; (iii) supine predominant OSA, 61.9%; and (iv) intermittent OSA, 12.4%. Patients categorized as having both REM and supine predominant OSA showed characteristics of both the REM predominant and supine predominant OSA groups. Conclusions: Patients with mild‐moderate OSA show different polysomnographic phenotypes. This approach to categorization more appropriately reflects disease heterogeneity and the likely multiple pathophysiological processes involved in OSA.