Preliminary study on clinical characteristics of Chinese patients with positional obstructive sleep apnea.

PURPOSE: The objective of this study was to evaluate the prevalence, the clinical characteristics, and the possible predictors of Chinese patients with positional obstructive sleep apnea (POSA) according to the Amsterdam Positional Obstructive Sleep Apnea Classification (APOC). METHODS: A retrospective study in the sleep unit of Peking Union Medical College Hospital was conducted to analyze the clinical and polysomnography data of Chinese patients with obstructive sleep apnea (OSA). RESULTS: Of 372 patients with OSA, 54% met the APOC criteria for POSA. The prevalence of POSA was significantly higher in women with OSA than in men. Chinese patients with POSA had a lower apnea-hypopnea index, oxygen desaturation index, and the percentage of time spent at oxygen saturation below 90% in total sleep time; and a higher mean oxygen saturation (SaO2) and minimum SaO2 during sleep, which were remarkable in the APOC I group. By multivariate logistic regression analyses, the higher mean SaO2 (≥95%) during sleep and mild and moderate OSA were positive predictors of POSA. Mild and moderate OSA was the independent predictor of POSA in women. Higher mean SaO2 (≥95%) during sleep was the independent predictor of POSA in men. CONCLUSION: According to the APOC, the prevalence of POSA is high in Chinese patients with OSA, especially in women. Chinese patients with POSA had less severe OSA and a lower degree of nocturnal hypoxia, which was remarkable in the APOC I group.

Fenotipos clínicos en el síndrome de apnea obstructiva del sueño / Clinical phenotypes in obstructive sleep apnea

El síndrome de apnea e hipopnea obstructiva del sueño se caracteriza por episodios repetitivos de obstrucción de vía aérea superior y es reconocida cada vez más, como un trastorno heterogéneo y complejo, proponiéndose múltiples fenotipos en base a su mecanismo patogénico, alteraciones polisomnográficas y la presentación clínica. El fenotipo clínico se enfoca en identificar características de un paciente basándose en signos, síntomas, antropometría, comorbilidades, medidas fisiológicas, anatómicas o respuesta al tratamiento. Al ser una enfermedad sub diagnosticada, de alta prevalencia y que produce elevada morbi-mortalidad, se debe estar atento a la pesquisa precoz y en las poblaciones de riesgo. Su diagnóstico se basa en el índice de apnea-hipopnea (IAH) y se requiere un IAH •5 eventos/hora para confirmar el diagnóstico. Sin embargo, cada vez hay más evidencia que el IAH por sí solo es insuficiente para comprender la presentación clínica, respuesta al tratamiento, calidad de vida y mortalidad de los pacientes con apnea del sueño. El fenotipo clínico puede servir de este modo, para entender mejor las diferentes formas de presentación teniendo como finalidad la medicina personalizada con el objetivo de favorecer la conducta terapéutica individualizada. El objetivo de esta revisión es abordar los fenotipos clínicos y proponer una huella digital en los pacientes con apnea del sueño

Obstructive sleep apnea and hypopnea syndrome is characterized by repetitive episodes of upper airway obstruction and is increasingly recognized as a heterogeneous and complex disorder, proposing multiple phenotypes based on its pathogenic mechanism, polysomnographic alterations, and clinical presentation. The clinical phenotype focuses on identifying a patient's characteristics based on signs, symptoms, anthropometry, comorbidities, physiological, anatomical measures or response to treatment. As it is an underdiagnosed disease of high prevalence associated to high morbidity and mortality, we must be alert to early screening and risk populations. Diagnosis is based on the apnea-hypopnea index (AHI) AHI •5 events/hour is required to confirm it, however, there is increasing evidence that AHI alone is insufficient to understand the clinical presentation, the response to treatment, the quality of life and the mortality of patients with sleep apnea. In this way, the clinical phenotype can serve to better understand the different forms of presentation and looks for a personalized medicine that favors an individualized therapeutic behavior. The aim of this review is to address clinical phenotypes and propose a fingerprint in patients with sleep apnea

Predictors of obstructive sleep apnea misclassification when using total bed time versus total sleep time.

Obstructive sleep apnea (OSA) is a highly prevalent condition worldwide. Untreated, it is associated with multiple medical complications as well as a reduced quality of life. Home sleep apnea tests are increasingly used for its diagnosis and evaluation of severity, but using total bed time rather than total sleep time may underestimate OSA severity. We aim to uncover the extent and predictors of OSA misclassification when using total bed time. A retrospective observational study was conducted using data from the sleep laboratory of the National University Hospital, Singapore, a tertiary hospital with 1200 beds. Misclassification of OSA was defined as any OSA severity that was less severe using total bed time versus total sleep time. Logistic regression was used to identify predictors of OSA misclassification. A total of 1621 patients were studied (mean age 45.6 ± 15.9 years; 73.4% male). 300 (18.5%) patients were misclassified. Risk factors for OSA misclassification included age (OR 1.02, 95% CI 1.01-1.03, P = 0.001) and body-mass index (BMI) (OR 0.97, 95% CI 0.95-0.99, P = 0.015). Risk for misclassification was significant in patients aged ≥ 57 years old, with BMI < 32.3 kg/m2. Using total bed time rather than total sleep time to quantify OSA severity was associated with a significant risk of misclassification, particularly in patients aged ≥ 57 years old, with BMI < 32.3 kg/m2.

Correlation between short-time and whole-night obstruction level tests for patients with obstructive sleep apnea.

Identification of obstructive level is crucial for successful surgical outcomes in patients with obstructive sleep apnea (OSA). Unfortunately, most of the dynamic airway evaluations are performed for a short duration under drug-induced sleep; therefore, it is uncertain whether they represent airway events that occur during a whole night of sleep. This study was aimed to evaluate the correlation between obstructive levels that were identified by a short-time and a whole-night test in patients with OSA. Total 101 patients with OSA underwent drug-induced sleep fluoroscopy (DISF) and pressure manometry (PM). For DISF, the obstructive pattern was classified into one of three groups: soft palate, tongue-based, and a combined obstruction. PM was used to measure the proportion of retroglossal events out of total whole-night obstructive events in each patient. The mean age of the patients was 43.8 years. The obstructive pattern was identified as soft palate in 56 patients, combined in 38 patients, and tongue-based in 7 patients following DISF. Results from PM showed that the mean percentage of retroglossal obstructive events was 31.2 ± 30.7%. The average proportion of retroglossal obstructive events that were identified by PM in patients with soft palate, combined, and tongue-based obstruction was 27.2%, 32.1%, and 59.0%, respectively (p = 0.033). There are limitations of evaluating obstructive events that occur during a whole night with short-time tests. Surgeons should be aware the possibility of disagreement in the obstructive level between short-time and whole-night tests.

Multi-perspective clustering of obstructive sleep apnea towards precision therapeutic decision including craniofacial intervention.

PURPOSE: Previous studies focusing on phenotyping obstructive sleep apnea (OSA) have outlined its heterogeneity in clinical symptoms, comorbidities, and polysomnographic features. However, the role of anatomical or pathophysiological causality including craniofacial skeletal deformity has not been studied. We aimed to identify and characterize phenotypes of OSA based on multi-perspective clustering by incorporating craniofacial risks with obesity, apnea severity, arousability, symptom, and comorbidity. METHODS: A total of 421 Korean patients with OSA (apnea-hypopnea index, AHI ≥ 5; age ≥ 20 years old) were recruited. A K-means cluster analysis was performed following principal component analysis with sagittal and vertical skeletal variables (ANB and mandibular plane angle), AHI, body mass index, and Epworth sleepiness scale. Inter-cluster comparison was conducted using demographic, cephalometric, and polysomnographic variables in addition to presence of diabetes and hypertension. Risk factors contributing to OSA severity were evaluated in each cluster using multivariable regression analysis with adjustment for age and gender. RESULTS: Three phenotypic clusters were identified and characterized as follows: Cluster-1 (noncraniofacial phenotype, 39%), non-obese moderate-to-severe OSA with no skeletal discrepancy representing low arousal threshold (ArTh), little sleepiness, and low comorbidity; Cluster-2 (craniofacial skeletal phenotype, 33%), non-obese moderate OSA with definite skeletal discrepancy showing low ArTh, mild sleepiness, and low comorbidity; and Cluster-3 (complicated phenotype, 28%), obese severe OSA with skeletal discrepancy exhibiting high ArTh, excessive daytime sleepiness, and high incidence of hypertension. CONCLUSIONS: The three OSA phenotypes from multi-perspective clustering may provide a basis for precise therapeutic decision-making including craniofacial skeletal intervention beyond usual characterization of OSA subgroups.

Predictive ability of the International Classification of Sleep Disorders-3 in identifying risk of obstructive sleep apnea among recently unemployed adults.

BACKGROUND: The International Classification of Sleep Disorders (ICSD)-3 was developed to aid in the identification of these disorders. The core criterion A (ICSD-3A) to identify obstructive sleep apnea (OSA) requires the presentence of specific signs and symptoms. This study explores the predictive ability of the ICSD-3A for OSA as compared with objective measures of respiratory event index (REI). PARTICIPANTS: A total of 291 participants who completed a home sleep apnea test (HSAT) during the screening evaluation of the Assessing Daily Activity Patterns through occupational Transitions (ADAPT) study were included. METHODS: Participants were classified as having mild OSA (REI ≥ 5 and < 15), moderate (≥ 15 to < 30), or severe OSA (> 30). Predictive parameters identifying participants as having OSA by the ICSD-3A criteria were assessed using REI classifications as the reference standard and further compared with a subsample using the STOP-Bang questionnaire. RESULTS: The ICSD-3A had a sensitivity of 19.2% for identifying participants as having moderate to severe OSA and specificity of 84.4%. The ICSD-3A had a receiver operating characteristics (ROC) = 0.53. On the subsample of participants, the STOP-Bang questionnaire's ROC is 0.61. Results were similar when examining the classification of participants with mild compared with no OSA. CONCLUSION: In this population, the ability of the ICSD-3A in detecting moderate to severe OSA as well as mild OSA was low. The ROC for the ICSD-3 did not differ significantly from the STOP-Bang questionnaire's ROC in this research population.

[Relationship between sleep architecture and severity of obstructive sleep apnea].

OBJECTIVE: To investigate the effect of obstructive sleep apnea (OSA) on different sleep stages, and the relationship between N3 stage of non-rapid eye movement sleep and respiratory abnormal events. METHODS: A total of 188 adult patients who underwent overnight polysomnography(PSG)monitoring in Sir Run Run shaw Hospital of Zhejiang University from June 24th to December 26th 2019 were enrolled in the study. OSA patients were classified into 3 groups (mild, moderate and severe) according to the apnea-hypopnea index (AHI). PSG data, AHI and the lowest SPO2 in each stage of sleep were compared among three groups. RESULTS: There was no significant difference in total sleep time and sleep efficiency among patients with different severity of OSA (all P>0.05). The proportion of N3 stage in moderate and severe OSA groups were significantly smaller than that in mild OSA group (all P<0.05). The proportion of N3 stage in severe OSA group was also smaller than that in moderate OSA group (P<0.05). In addition, severe OSA group had a longer latency of N3 stage than mild and moderate OSA groups (all P<0.05). The latency of N3 stage in moderate OSA group was longer than that in mild OSA group (P<0.05). The AHI in N3 stage was markedly lower than that in other sleep stages (all P<0.01), regardless of the severity of OSA. Supine AHI in N3 stage in mild and moderate groups was significantly lower than that in N1, N2 and rapid eye movement (REM) stages (all P<0.01). Supine AHI in N3 stage in severe group was also lower than that in N2 and REM stages (P<0.05 or P<0.01). The lowest SPO2 in N3 stage was significantly higher than that in N1, N2 and REM stages (P<0.05 or P<0.01), regardless of the severity of OSA. CONCLUSIONS: s The proportion of N3 stage is lower in OSA patients, and N3 stage has less sleep respiratory events than non-N3 stages. The results suggest that the increased N3 stage proportion may indicate less severity of OSA.

Performance of brief ICF-sleep disorders and obesity core set in obstructive sleep apnea patients.

BACKGROUND: Clinical questionnaires are mainly applied as screening tools for identification of the Obstructive sleep apnea (OSA) patients. Little attention has been paid to assess the body functions and health status of the patients. International Classification of Functioning, Disability and Health (ICF) was designed for better understanding and describing functioning and disability of patients. This study adopted the Brief ICF-Sleep Disorders and Obesity Core Set to evaluate the impairment of functioning and health status of OSA patients. METHODS: Five hundred ninety-two participants were enrolled in this cross-sectional study. Data were collected using Brief ICF-Sleep Disorders and Obesity Core Set Polysomnography was performed and basic characteristics of the patients were recorded. RESULTS: The scores for the component Body Functions and Code b130, b134, b140, b440, b530, s330, d160, d240, d450 of the two core sets were significantly different among the patients divided by apnea-hypopnea index (AHI) or oxygen saturation (SaO2) nadir, but the frequency of code s330, d160, d240, d450 was low. The Body Functions component of the both sets were closely related to neck circumference (NC), body mass index (BMI), apnea-hypopnea index (AHI) of the OSA patients. Body Functions of the Brief ICF-Sleep Disorders performed better with a threshold of 4 with sensitivity, specificity and area under the receiver operating characteristic curve (AUC) as 0.62, 0.74, 0.68(AHI ≥ 5), 0.69, 0.63, 0.66 (AHI ≥ 15), 0.75, 0.56, 0.66 (AHI ≥ 30), 0.56, 0.70, 0.63 (SaO2 nadir≤90%), 0.67, 0.66, 0.66 (SaO2 nadir<85%), 0.71, 0.59, 0.65 (SaO2 nadir<80%), separately. CONCLUSION: The Body Functions component of both two sets could be an evaluation tool of impairment of body functions for OSA patients. The Brief ICF-Sleep Disorders Body Functions component performed better with a threshold of 4 and might provide a new insight for physicians to assess OSA patients.

Defining Extreme Phenotypes of OSA Across International Sleep Centers.

BACKGROUND: Extreme phenotypes of OSA have not been systematically defined. RESEARCH QUESTION: This study developed objective definitions of extreme phenotypes of OSA by using a multivariate approach. The utility of these definitions for identifying characteristics that confer predisposition toward or protection against OSA is shown in a new prospective sample. STUDY DESIGN AND METHODS: In a large international sample, race-specific liability scores were calculated from a weighted logistic regression that included age, sex, and BMI. Extreme cases were defined as individuals with an apnea-hypopnea index (AHI) ≥ 30 events/hour but low likelihood of OSA based on age, sex, and BMI (liability scores > 90th percentile). Similarly, extreme controls were individuals with an AHI < 5 events/hour but high likelihood of OSA (liability scores < 10th percentile). Definitions were applied to a prospective sample from the Sleep Apnea Global Interdisciplinary Consortium, and differences in photography-based craniofacial and intraoral phenotypes were evaluated. RESULTS: This study included retrospective data from 81,338 individuals. A total of 4,168 extreme cases and 1,432 extreme controls were identified by using liability scores. Extreme cases were younger (43.1 ± 14.7 years), overweight (28.6 ± 6.8 kg/m2), and predominantly female (71.1%). Extreme controls were older (53.8 ± 14.1 years), obese (34.0 ± 8.1 kg/m2), and predominantly male (65.8%). These objective definitions identified 29 extreme cases and 87 extreme controls among 1,424 Sleep Apnea Global Interdisciplinary Consortium participants with photography-based phenotyping. Comparisons suggest that a greater cervicomental angle increases risk for OSA in the absence of clinical risk factors, and smaller facial widths are protective in the presence of clinical risk factors. INTERPRETATION: This objective definition can be applied in sleep centers throughout the world to consistently define OSA extreme phenotypes for future studies on genetic, anatomic, and physiologic pathways to OSA.

Journey towards a personalised medicine approach for OSA: Can a similar approach to adult OSA be applied to paediatric OSA?

The concept of personalised medicine is likely to revolutionise the treatment of adult obstructive sleep apnoea as a result of recent advances in the understanding of disease heterogeneity by identifying clinical phenotypes, pathophysiological endotypes, biomarkers and treatable traits. Children with the condition show a similar level of heterogeneity and paediatric obstructive sleep apnoea would also benefit from a more targeted approach to diagnosis and management. This review aims to summarise the adult literature on the phenotypes and endotypes of obstructive sleep apnoea and assess whether a similar approach may also be suitable to guide the development of new diagnostic and management approaches for paediatric obstructive sleep apnoea.

Phenotypic Subtypes of OSA: A Challenge and Opportunity for Precision Medicine.

Current strategies for the management of OSA reflect a one-size-fits-all approach. Diagnosis and severity of OSA are based on the apnea-hypopnea index and treatment initiated with CPAP, followed by trials of alternatives (eg, oral appliances) if CPAP "fails." This approach does not consider the heterogeneity of individuals with OSA, reflected by varying risk factors, pathophysiological causes, clinical manifestations, and consequences. Recently, studies using analytic approaches such as cluster analysis have taken advantage of this heterogeneity to identify OSA phenotypes, or subtypes of patients with unique characteristics, that may enable more personalized approaches to prognostication and treatment. Examples include symptom-based subtypes such as "excessively sleepy" and "disturbed sleep" with differing impact of CPAP on symptoms and health-related quality of life. Polysomnographic subtypes, distinguished by respiratory event association with hypoxemia, arousals, or both, exhibit varying risks of cardiovascular disease and response to therapy. This review summarizes the findings from recent cluster analysis studies in sleep apnea and synthesizes common themes to describe the potential role (and limitations) of phenotypic subtypes in precision medicine for OSA. It also highlights future directions, including linking of phenotypes to clinically relevant outcomes, rigorous and transparent assessment of phenotype reproducibility, and need for tools that categorize patients into subtypes, to prospectively validate phenotype-based prognostication and treatment approaches. Finally, we highlight the critical need to include women and more racially/ethnically diverse populations in this area of research if we are to leverage the heterogeneity of OSA to improve patient lives.

Effect of mean apnea-hypopnea duration in patients with obstructive sleep apnea on clinical and polysomnography parameter.

OBJECTIVE: Apnea-hypopnea index is the number of apnea-hypopnea events observed during polysomnography within an hour. Mean apnea-hypopnea duration is the mean duration of all apneas and hypopneas. In this study, we aimed to investigate the association of mean apnea-hypopnea duration in patients with obstructive sleep apnea with clinical and polysomnographic parameters. METHODS: In our hospital, a total of 764 patients were diagnosed with OSA by polysomnography in 2017. Age, body mass index, and the current diseases were recorded. Sleep structures obtained from polysomnography readings, blood oxygen levels, apnea-hypopnea index, and mean average duration were recorded. Patients with mean average duration of 20 s or more were assigned to the long average duration group and those with less than 20 s were assigned to the short average duration group. Groups were compared in terms of clinical and polysomnographic parameters. RESULTS: Snoring, witnessed apnea, morning tiredness, and hypertension were significantly higher in the long average duration group. There was statistically significantly more male patients and higher neck circumference in the MAD group. Total wake duration, percentage of sleep, stage 3, stage 1, and mean oxygen saturation percentage of the long average duration group were significantly reduced. CONCLUSION: In present study, the patients with obstructive sleep apnea with long average duration were found to have more negative effects of sleep apnea than the patients with short average duration. We think that the use of mean apnea-hypopnea duration as an indicator with apnea-hypopnea index will be beneficial for the follow-up and treatment of the disease.

Is image interpretation in drug-induced sleep endoscopy that reliable?

PURPOSE: Previous studies have assessed drug-induced sleep endoscopy (DISE) as an interobserver reliable exam, with a learning curve effect. The objective was to check its assumed interobserver agreement and variability of between two groups of experienced and inexperienced French ENT physicians. METHODS: Prospective study. Seventy-six French ENT physicians (69 inexperienced in DISE and seven experienced) observed seven DISE videos. They were asked to determine the level(s), the configuration, and the degree of collapse, according to the VOTE classification. Specific and global agreements using the Fleiss' Kappa coefficient (k) were calculated. RESULTS: The interobserver agreement varied from poor to good in determining the level; the best agreement being found for the oropharynx (global agreement = 0.82 and k = 0.6 in the experienced group, global agreement = 0.87 and k = 0.7 in the inexperienced group), followed by the soft palate and the larynx; the worst agreement being found for the tongue base (k = 0.29 in the experienced group and k = 0.38 in the inexperienced group). The agreement for the configuration and the degree of collapse was moderate except for the tongue base where the concordance was poor. In both groups, agreement was at best good without any statistically significant difference between the two levels of experience groups. CONCLUSION: Even in a French ENT Sleep Experts group, DISE appears to be a technique with a limited interobserver agreement in the detection of obstructive sites, without any learning curve effect. In its current state, DISE interpretation may not be totally reliable.

Magnitude and Determinants of Patients at Risk of Developing Obstructive Sleep Apnea in a Non-Communicable Disease Clinic.

Background and Objective: Obstructive sleep apnea (OSA) is a common chronic disorder worldwide, which can adversely affect the cardiovascular system among non-communicable disease (NCD) patients. It is underdiagnosed-or rather not diagnosed-in primary care settings due to the costly diagnostic techniques involved. This study aimed to assess the number of study participants at risk of developing OSA and to assess and quantify the risk factors associated with this disorder. Materials and Methods: A cross-sectional study was performed in an NCD clinic of a rural health training center, Karikalampakkam, Puducherry of South India from August 2018 to October 2018. A Modified Berlin Questionnaire (MBQ) was used to screen the study participants at risk for OSA. Four-hundred-and-seventy-three people aged 18 years and above were included in the study, using systematic random sampling. Respondents' socio-demographic and morbidity characteristics, as well as clinical and anthropometric parameters including body weight, height, blood pressure, neck, hip and waist circumference were collected. Data was captured using Epicollect5 and analyzed using SPSS version 20.0. Results: One-fourth (25.8%) of the respondents were at high risk of developing OSA. In terms of gender, 27.9% of the men and 23.8% of the women were at high risk for OSA. In univariate analyses, the risk of developing OSA was significantly associated with a history of diabetes mellitus, hypertension, dyslipidemia and gastro-esophageal reflux disease, weight, body mass index, neck, waist and hip circumference, waist-hip ratio, and systolic and diastolic blood pressure. Multivariate logistic regression analysis showed that a history of dyslipidemia (aOR, 95% CI = 2.34, 1.22-4.48), body mass index (aOR, 95% CI = 1.15, 1.06-1.22) and waist circumference (aOR, 95% CI = 1.10, 1.07-1.14) emerged as significant predictors of risk for OSA. Conclusions: A considerable proportion of NCD patients with easily detectable attributes are at risk of developing OSA, but still remain undiagnosed at a primary health care setting. The results obtained using MBQ in this study were comparable to studies performed using polysomnography. Dyslipidemia, body mass index and waist circumference were independent risk factors for predicting a risk of developing OSA. Prospective studies are needed to confirm whether a reduction in these risk factors could reduce the risk for OSA.

Anthropometric Measures and Prediction of Maternal Sleep-Disordered Breathing.

STUDY OBJECTIVES: Pregnant women are at risk for sleep-disordered breathing (SDB); however, screening methods in this dynamic population are not well studied. The aim of this study was to examine whether anthropometric measures can accurately predict SDB in pregnant women. METHODS: Pregnant women with snoring and overweight/obesity were recruited in the first trimester. Anthropometric measures were performed according to the International Standards for Anthropometric Assessment, including a seated neutral and extended neck Mallampati class. Home sleep apnea monitoring was performed using a level III device after completion of anthropometric assessment. SDB was defined as an apnea-hypopnea index ≥ 5 events/h of sleep. Pearson and Spearman tests examined correlations between various measures. Generalized linear models, sensitivity, specificity, and area under the curve as well as odds ratios were performed to test the model. RESULTS: A total of 129 participants were recruited, and 23 had SDB. Average gestational age was 10.6 ± 1.9 weeks. Due to concerns over multicollinearity, the final model included extended Mallampati class and upright neck circumference. Neck circumference was significantly higher in participants with Mallampati classes 2/3 and grade 4 compared to participants with Mallampati class 1 (P = .0005). Increasing neck circumference was associated with higher odds of SDB (P = .0022). In Mallampati class 1, odds ratio for SDB was 2.89 (1.19, 7.03) per unit increase in neck circumference. CONCLUSIONS: Modeling neck circumference while allowing for differences by Mallampati class showed a nearly threefold increase in the risk of SDB with increasing neck circumference in women with Mallampati class 1. Other potential sites of airway obstruction need to be investigated in future research.

A new simple efficient classification technique for severity of sleep apnea with mathematical model and interpretation.

BACKGROUND: Obstructive Sleep Apnea (OSA) is the cessation of breathing during sleep due to the collapse of the upper airway. Polysomnographic recording is a conventional method for detection of OSA. Although it provides reliable results, it is expensive and cumbersome. Thus, an advanced non-invasive heart rate variability (HRV) signal processing technique other than the standard spectral analysis, which also has efficiency limitations, is needed for identification of OSA and classification of apnea levels. OBJECTIVE: The main purpose of this work was to predict the severity of sleep apnea using an efficient method based on the combination of time-domain and frequency-domain analysis of the HRV to classify sleep apnea into three different levels (mild, moderate, and severe) according to its severity and to distinguish them from normal subjects. METHODS: The statistical signal characterization of the FFT-based spectrum of the RRI data is used in this work in order to rank patients to full polysomnography. Data of 20 normal subjects, 20 patients with mild apnea, 20 patients with moderate apnea and 20 patients with severe apnea were used in this study. RESULTS: Accuracy result of 100% was obtained between severe and normal subjects, 100% between mild and normal subjects, and 100% between apnea (mild, moderate, severe) and normal subjects. This perfect accuracy is obtained using the parameter mean (mt). The physiological interpretation of the SSC parameters has been derived using a mathematical model system. CONCLUSIONS: An efficient method for screening of sleep apnea with 100% efficiency in classification of sleep apnea levels, is investigated in this work.

Predictors of moderate to severe obstructive sleep apnea: identification of sex differences.

PURPOSE: Home sleep apnea tests are recommended only for patients at high risk of moderate to severe obstructive sleep apnea (OSA, apnea-hypopnea index [AHI] ≥ 15/h). We evaluated 14 factors known to be associated with OSA and identified sex differences in predictors of moderate to severe OSA. METHODS: Retrospective analysis was done on 545 subjects who completed sleep questionnaires and underwent diagnostic polysomnogram at a tertiary sleep center. Univariate and multivariate analysis was conducted separately in males and females to determine which variables were independent predictors of moderate to severe OSA. RESULTS: Overall, physical traits were stronger predictors in both males and females. For each sex, only 3 variables were found to be independently predictive of moderate to severe OSA. In order of predictive strength, this included body mass index (BMI) ≥ 38 kg/m2 (aOR 5.80, p < 0.001), neck circumference (NC) ≥ 17 in. (aOR 2.52, p = 0.002), and Epworth sleepiness scale (ESS) ≥ 13 (aOR 2.22, p = 0.015) for males and age ≥ 50 years (aOR 4.19, p < 0.001), NC ≥ 14.5 in. (aOR 3.13, p = 0.003), and report of morning headaches (aOR 2.00, p = 0.039) for females. Applying the Bonferroni correction, BMI and NC remained significant for males, and age and NC remained significant for females. CONCLUSIONS: In a subject population referred for sleep evaluation at a tertiary care center only a few variables are independently predictive of moderate to severe OSA, and these variables differed between males and females. Only BMI, NC, and a high ESS were independently predictive of moderate to severe OSA in males, whereas age, NC, and morning headaches were independently predictive in females.

Symptom Subtypes of Obstructive Sleep Apnea Predict Incidence of Cardiovascular Outcomes.

Rationale: Symptom subtypes have been described in clinical and population samples of patients with obstructive sleep apnea (OSA). It is unclear whether these subtypes have different cardiovascular consequences.Objectives: To characterize OSA symptom subtypes and assess their association with prevalent and incident cardiovascular disease in the Sleep Heart Health Study.Methods: Data from 1,207 patients with OSA (apnea-hypopnea index ≥ 15 events/h) were used to evaluate the existence of symptom subtypes using latent class analysis. Associations between subtypes and prevalence of overall cardiovascular disease and its components (coronary heart disease, heart failure, and stroke) were assessed using logistic regression. Kaplan-Meier survival analysis and Cox proportional hazards models were used to evaluate whether subtypes were associated with incident events, including cardiovascular mortality.Measurements and Main Results: Four symptom subtypes were identified (disturbed sleep [12.2%], minimally symptomatic [32.6%], excessively sleepy [16.7%], and moderately sleepy [38.5%]), similar to prior studies. In adjusted models, although no significant associations with prevalent cardiovascular disease were found, the excessively sleepy subtype was associated with more than threefold increased risk of prevalent heart failure compared with each of the other subtypes. Symptom subtype was also associated with incident cardiovascular disease (P < 0.001), coronary heart disease (P = 0.015), and heart failure (P = 0.018), with the excessively sleepy again demonstrating increased risk (hazard ratios, 1.7-2.4) compared with other subtypes. When compared with individuals without OSA (apnea-hypopnea index < 5), significantly increased risk for prevalent and incident cardiovascular events was observed mostly for patients in the excessively sleepy subtype.Conclusions: OSA symptom subtypes are reproducible and associated with cardiovascular risk, providing important evidence of their clinical relevance.

Apnea and hypopnea characterization using esophageal pressure, respiratory inductance plethysmography, and suprasternal pressure: a comparative study.

OBJECTIVES: To determine if recording of suprasternal pressure (SSP) can classify apneas and hypopneas as reliably as respiratory inductance plethysmography (RIP) belts and to compare the two methods to classification with esophageal pressure (Pes), the reference method for assessing respiratory effort. METHODS: In addition to polysomnographic recordings that included Pes, SSP was recorded. Recordings from 32 patients (25 males, mean age 66.7 ± 15.3 years, and mean BMI 30.1 ± 4.5 kg/m2) were used to compare the classification of detected apneas and hypopneas by three methods of respiratory effort evaluation (Pes, RIP belts, and SSP). Signals were analyzed randomly and independently from each other. All recordings were analyzed according to AASM guidelines. RESULTS: Using Pes as a reference for apnea characterization, the Cohen kappa (κ) was 0.93 for SSP and 0.87 for the RIP. The sensitivity/specificity of SSP was 97.0%/96.9% for obstructive, 93.9%/98.3% for central, and 94.9%/97.9% for mixed apneas. The sensitivity/specificity of the RIP was 97.4%/91.9% for obstructive, 87.5%/97.9% for central, and 85.6%/96.6% for mixed apneas. For hypopnea characterization using the Pes as a reference, κ was 0.92 for SSP and 0.86 for the RIP. The sensitivity/specificity of SSP was 99.7%/97.6% for obstructive and 97.6%/99.7% for central. The sensitivity/specificity of the RIP was 99.8%/81.1% for obstructive and 81.1%/99.8% for central. CONCLUSIONS: These results confirm the excellent agreement in the detection of respiratory effort between SSP, RIP belts, and Pes signals. Thus, we conclude that apnea and hypopnea characterization in adults with SSP is a reliable method.