Severity of individual obstruction events is gender dependent in sleep apnea

Nocturnal short-term heart rate variability reflects impaired daytime vigilance better than overnight heart rate variability in suspected obstructive sleep apnea patients

In obstructive sleep apnea (OSA), heart rate variability (HRV) decreases and performance in psychomotor vigilance task (PVT) worsens with more severe hypoxic load. Nevertheless, the association between HRV and PVT performance is poorly understood. Thus, we hypothesize that nocturnal short-term HRV is better related to daytime psychomotor vigilance compared with overnight HRV. To investigate this hypothesis, we retrospectively analyzed the electrocardiograms from polysomnographies of 546 consecutive patients with suspected OSA. We determined overnight HRV and short-term HRV in nonoverlapping 5-min segments and performed stepwise linear regression analyses to associate HRV with the median reaction time (RT) in the PVT. The short-term decrease in the median interval between two successive normal R peaks (NN interval), root mean square of successive NNs, and normalized high-frequency band power were all significant (p < 0.001) indicators of longer median RTs. However, the overnight HRV parameters did not indicate worsening median RT. Instead, increased hypoxic load and N3 duration were associated with longer median RT in men but not in women. The association of HRV and cardiorespiratory coupling with PVT performance was generally weak. Nocturnal short-term HRV evaluation reflected a state of vigilance better than the average overnight HRV. Thus, the overnight HRV analysis might not be optimal for patients with OSA. Utilizing the HRV analysis in a time-series manner and combined with the hypoxic load and sleep stages could bring new aspects to the health assessment of patients with OSA.

Improving the cardiovascular outcomes of obstructive sleep apnea: Towards more precise hypoxia-based models of disease severity

Purpose of review

Obstructive sleep apnea (OSA) affects at least 1 billion people worldwide, and its increasing prevalence is alarming considering an association to comorbidities such as cardiovascular disease (CVD) and to demonstrated health disparities. This raises concerns regarding the current diagnostic standards, which are also impacted by disparities. The current review was aimed at identifying limitations in the apnea-hypopnea index (AHI), the primary clinical indicator of OSA severity, and analyzing recent alternatives. In addition, the association between OSA and CVD was discussed, and, considering the role of intermittent hypoxia, solutions were proposed for improving OSA diagnosis.

Recent findings

Based on a review of current literature, alternative metrics to the AHI such as the hypoxia burden, sleep apnea-specific pulse rate, and oxygen desaturation rate were shown to be correlated with indicators of CVD in OSA patients. A recent mathematical study also presents the possibility of a model-based metric to eliminate existing bias in diagnostics and provide a more accurate quantification of tissue hypoxia.

Summary

The analyzed studies give incentive to look beyond current clinical standards in OSA. Through this review, we motivate the use of mathematical modeling as a future avenue to improve OSA diagnosis with a hypoxia-based approach.

Apnea-hypopnea duration may be a better choice rather than apnea-hypopnea index for forecasting complications in OSAS

OBJECTIVE

Mean apnea-hypopnea duration (AHD) is the mean duration of apnea-hypopneas experienced during sleep and was found as an indicator of blood oxygenation. The aim of this study was to compare and define the differences in clinical, demographic and polysomnographic characteristics of obstructive sleep apnea (OSA) patients in long and short AHD groups and investigate the relationship between apnea-hypopnea index (AHI), oxygen desaturation index (ODI), and sleepiness.

METHODS

The cross-sectional analysis included 511 OSA patients who were >18 years and followed up between June 2019 and December 2019 in the Sleep Center of university hospital. The consecutive polysomnography reports and patient data were recorded retrospectively.

RESULTS

Polysomnographic evaluation of different AHD groups showed obvious differences. Although there were no statistically significant differences in the overall AHI values. The Epworth measurements, ODI, time that saturation is below 90%, and N1 and N2 sleep were higher in the long AHD group. On the contrary, sleep efficiency, total sleep time, N3 and REM sleep, average oxygen saturation (AOS), and lowest oxygen saturation (LOS) were lower in the long AHD group.

CONCLUSIONS

The findings of this study showed that the AHD is a useful indicator of blood oxygenation and, therefore, tissue oxygenation, independent of the AHI. OSA patients with longer AHD have more vascular complications such as diabetes and hypertension. We suggest that the severity of OSA should be monitored with AHD for preventing potential complications of OSA.

Gender differences in obstructive sleep apnea syndrome: a pilot study

PURPOSE

OSAS is a syndrome that often presents clinically differently between men and women. The aim of this study was to assess the clinical presentation, nocturnal home sleep cardiorespiratory monitoring and therapeutic adherence to CPAP in both sexes to identify the most frequent patterns.

METHODS

Data from the first visit, the nocturnal home sleep cardiorespiratory monitoring and follow-up visit of 74 OSA patients were collected. Exclusion criteria included other respiratory and/or neuromuscular diseases (including Obesity hypoventilation syndrome) and other non-respiratory sleep disorders.

RESULTS

Men were older and had a higher supine AHI and ODI compared to women. In addition, BMI and age correlated positively with AHI in males. Women had a higher hypopneas frequency and better therapeutic adherence to CPAP.

CONCLUSIONS

Men were associated with a higher AHI when sleeping in the supine position and this may be useful to look for new therapeutic options in combination with or as an alternative to CPAP. BMI correlated positively with AHI in men and this should be considered to stimulate weight loss as the main treatment to reduce the number of apneas/hypopneas, as men also had less therapeutic adherence to CPAP in our study. Females presented a significantly higher frequency of hypopneas than men, as well as a lower number of desaturation events per hour (ODI): these differences in the nocturnal home sleep cardiorespiratory monitoring could reflect different pathophysiological mechanisms of OSAS onset between the two sexes, which should be investigated in future scientific studies.

Chronic intermittent hypoxia-induced hypertension: the impact of sex hormones

Obstructive sleep apnea, a common form of sleep-disordered breathing, is characterized by intermittent cessations of breathing that reduce blood oxygen levels and contribute to the development of hypertension. Hypertension is a major complication of obstructive sleep apnea that elevates the risk of end-organ damage. Premenopausal women have a lower prevalence of obstructive sleep apnea and cardiovascular disease than men and postmenopausal women, suggesting that sex hormones play a role in the pathophysiology of sleep apnea-related hypertension. The lack of protection in men and postmenopausal women implicates estrogen and progesterone as protective agents but testosterone as a permissive agent in sleep apnea-induced hypertension. A better understanding of how sex hormones contribute to the pathophysiology of sleep apnea-induced hypertension is important for future research and possible hormone-based interventions. The effect of sex on the pathophysiology of sleep apnea and associated intermittent hypoxia-induced hypertension is of important consideration in the screening, diagnosis, and treatment of the disease and its cardiovascular complications. This review summarizes our current understanding of the impact of sex hormones on blood pressure regulation in sleep apnea with a focus on sex differences.

Reaction time in psychomotor vigilance task is related to hypoxic load in males with sleep apnea

Oxygen saturation (SpO2 )-based parameters are more strongly linked to impaired daytime vigilance than the conventional diagnostic metrics in patients with obstructive sleep apnea (OSA). However, whether the association between SpO2 -based parameters and impaired daytime vigilance is modulated by sex, remains unknown. Hence, we investigated the interplay between sex and detailed SpO2 -based metrics and their association with impaired vigilance in patients with OSA. The study population consisted of 855 (473 males, 382 females) patients with suspected OSA who underwent overnight polysomnography and psychomotor vigilance task (PVT). The population was grouped by sex and divided into quartiles (Q1-Q4) based on median reaction times (RTs) in the PVT. In addition to conventional diagnostic metrics, desaturation severity (DesSev), fall severity (FallSev), and recovery severity (RecovSev) were compared between the sexes and between the best (Q1) and worst (Q4) performing quartiles by using cumulative distribution functions (CDFs). Additionally, sex-specific covariate-adjusted linear regression models were used to investigate the connection between the parameters and RTs. The CDFs showed significantly higher hypoxic load in Q4 in males compared to females. In addition, the DesSev (β = 8.05, p < 0.01), FallSev (β = 6.48, p = 0.02), RecovSev (β = 9.13, p < 0.01), and Oxygen Desaturation Index (β = 12.29, p < 0.01) were associated with increased RTs only in males. Conversely, the Arousal Index (β = 10.75-11.04, p < 0.01) was associated with impaired vigilance in females. The severity of intermittent hypoxaemia was strongly associated with longer RTs in males whereas the Arousal Index had the strongest association in females. Thus, the impact of hypoxic load on impaired vigilance seems to be stronger in males than females.

Outcomes in Patients with Acute Myocardial Infarction and Known Sleep Apnea: A Nationwide Analysis

Background. Sleep apnea (SA) is a common breathing disorder characterized by repetitive upper airway narrowing and closure. Although SA has been demonstrated to be an independent risk factor for all-cause mortality, the direct contribution of SA to worse cardiovascular prognosis may be difficult to evaluate, and its independent association with the different types of cardiovascular outcomes may be debated, particularly in the context of patients with acute myocardial infarction (AMI). The aim of this study was to assess the impact of known SA on the outcomes of hospitalized patients who have had an AMI by analyzing 10-year data collected from a national registry. Methods. This longitudinal cohort study was based on the national hospitalization database that covers hospital care for the entire French population, including all patients admitted with AMI from January 2010 to June 2019. The clinical outcomes for the analysis were as follows: all-cause death, cardiovascular death, ischemic stroke, new-onset atrial fibrillation (FA), and re-hospitalization for heart failure (HF). Results. Among the 797,212 patients who presented with an AMI (528,351 men and 268,861 women), 37,075 (4.7%) had documented SA. During follow-up (mean [SD] 1.8 [2.4] years, median [interquartile range] 0.7 [0.1-3.1] years), 163,845 deaths (of which 85,649 were cardiovascular deaths), 20,168 ischemic strokes, 58,498 new-onset AF, and 92,381 rehospitalizations due to HF were recorded. Patients with known SA had a worse prognosis in the short and medium term, but after adjusting for all covariables, SA was only independently associated with a higher risk of rehospitalization for HF and new-onset AF in men and women. Conclusion. Data from our large nationwide analysis confirm that known SA is associated with poor cardiovascular outcomes in patients who have had an AMI. However, this impact is tem-pered when the model is adjusted for age, cardiovascular risk, or other covariables. Further studies need to be conducted to assess the independent impact of SA on the prognosis of patients with AMI.

International Consensus Statement on Obstructive Sleep Apnea

BACKGROUND

Evaluation and interpretation of the literature on obstructive sleep apnea (OSA) allows for consolidation and determination of the key factors important for clinical management of the adult OSA patient. Toward this goal, an international collaborative of multidisciplinary experts in sleep apnea evaluation and treatment have produced the International Consensus statement on Obstructive Sleep Apnea (ICS:OSA).

METHODS

Using previously defined methodology, focal topics in OSA were assigned as literature review (LR), evidence-based review (EBR), or evidence-based review with recommendations (EBR-R) formats. Each topic incorporated the available and relevant evidence which was summarized and graded on study quality. Each topic and section underwent iterative review and the ICS:OSA was created and reviewed by all authors for consensus.

RESULTS

The ICS:OSA addresses OSA syndrome definitions, pathophysiology, epidemiology, risk factors for disease, screening methods, diagnostic testing types, multiple treatment modalities, and effects of OSA treatment on multiple OSA-associated comorbidities. Specific focus on outcomes with positive airway pressure (PAP) and surgical treatments were evaluated.

CONCLUSION

This review of the literature consolidates the available knowledge and identifies the limitations of the current evidence on OSA. This effort aims to create a resource for OSA evidence-based practice and identify future research needs. Knowledge gaps and research opportunities include improving the metrics of OSA disease, determining the optimal OSA screening paradigms, developing strategies for PAP adherence and longitudinal care, enhancing selection of PAP alternatives and surgery, understanding health risk outcomes, and translating evidence into individualized approaches to therapy.

A comparison of cardiovascular disease associations of time-domain oximetry parameters in sleep apnoea cases from the Sleep Heart Health Study

Polysomnograms (PSGs) contain a wealth of physiological information that is routinely recorded but not utilised in sleep studies. Intermittent hypoxia arising from obstructive sleep apnoea (OSA) events is an important risk in the later development of cardiovascular disease (CVD). Analysis of oximetry patterns from PSG studies may enable early assessment of CVD risk. The aim of this study was to compare associations of different time-domain oximetry patterns with incident CVD in OSA patients. All participants with OSA and no pre-existing CVD at baseline or within the first two years of follow-up, were selected from the Sleep Heart Health Study data and used for analysis (N=2878). We examined oximetry parameters that are calculated from desaturation events and from time series analysis and compared them to incident CVD outcomes using proportional hazards regression models adjusted for age, race, smoking, BMI, and sex. Our results show that were no associations between OSA oximetry parameters and incident CVD for OSA patients.

Duration of respiratory events in obstructive sleep apnea: Factors influencing the duration of respiratory events

Several factors influence respiratory event duration during sleep. In general, women have shorter respiratory events compared to men as it appears that women have a more reactive upper airway contributing to the occurrence of short events. In addition, the increased amount of adipose tissue in the upper airways should make the reopening of the upper airways more difficult, leading to long respiratory events. Nevertheless, an increase in body mass index decreases the median duration of apneas, hypopneas, and desaturations in all OSA severity categories. Also, respiratory events are longer in older adults compared to younger ones, and the most likely mechanism explaining this phenomenon appears to be the increased circulatory delay associated with aging. Several studies have also shown that apnea events are longer in rapid eye movement sleep compared to non-rapid eye movement sleep. The main mechanism behind these differences appears to be the greater pharyngeal muscle relaxation during rapid eye movement sleep. Finally, sleeping position affects the duration of respiratory events; apneas and hypopneas are longer in the supine compared to lateral postures regardless of the severity of OSA. In the present report, we discuss the best-known factors influencing the duration of abnormal breathing events during sleep.

Duration of respiratory events in obstructive sleep apnea: In search of paradoxical results

Research related to the duration of respiratory events in obstructive sleep apnea (OSA) has been scarce, perhaps due to the dominant role played by the apnea-hypopnea index (AHI) in the diagnosis and severity estimation of OSA. Lately, however, researchers and clinicians have started to acknowledge the importance of this overlooked parameter. Intuitively, 40-s-long apneas have more harmful physiological and health consequences than 10-s-long apneas. But is this the case? Here, we review the research-based evidence showing physiological, hemodynamic, clinical, sleep quality, and health consequences of long vs. short respiratory events. Most of the reviewed studies support the idea that longer respiratory events have more severe physiological and clinical consequences than shorter events, most probably due to the higher hypoxic burden associated with longer respiratory events. However, a few but highly qualified studies provide clear evidence that short respiratory events have also a deleterious effect on sleep and the physiological and clinical aspects of OSA. The somewhat paradoxical findings that short respiratory events are also associated with a high risk of all-cause mortality is a serious concern. From these results, it is therefore evident that the duration of respiratory events should be quantified when diagnosing and assessing the severity of OSA.

Sex and Gender in Lung Disease and Sleep Disorders: A State-of-the-Art Review

The terms sex and gender often are used interchangeably, but have specific meaning when it comes to their effects on lung disease. Ample evidence is now available that sex and gender affect the incidence, susceptibility, presentation, diagnosis, and severity of many lung diseases. Some conditions are more prevalent in women, such as asthma. Other conditions are seen almost exclusively in women, like lymphangioleiomyomatosis. Some life stages-such as pregnancy-are unique to women and can affect the onset and course of lung disease. Clinical presentation may differ as well, such as higher number of exacerbations experienced by women with COPD and greater cardiovascular morbidity in women with sleep-disordered breathing. In addition, response to therapy and medication safety may also differ by sex, and yet, pharmacogenomic factors often are not addressed adequately in clinical trials. Various aspects of lung and sleep biology and pathobiology are impacted by female sex and female reproductive transitions. Differential gene expression or organ development can be impacted by these biological differences. Understanding these differences is the first step in moving toward precision medicine for women. This article is a state-of-the-art review of specific effects of sex and gender focused on epidemiology, disease presentation, risk factors, and management of lung diseases. Pathobiological mechanisms explaining sex differences in these diseases are beyond the scope of this article. We review the literature and focus on recent guidelines about using sex and gender in research. We also review sex and gender differences in lung diseases.

Comparative associations of oximetry patterns in Obstructive Sleep Apnea with incident cardiovascular disease

STUDY OBJECTIVES

Intermittent hypoxia is a key mechanism linking Obstructive Sleep Apnea (OSA) to cardiovascular disease (CVD). Oximetry analysis could enhance understanding of which OSA phenotypes are associated with CVD risk. The aim of this study was to compare associations of different oximetry patterns with incident CVD in men and women with OSA.

METHODS

Sleep Heart Health Study data were used for analysis. n = 2878 Participants (51.8% female; mean age 63.5 ± 10.5 years) with OSA (Apnea Hypopnea Index [AHI] ≥ 5 events/h) and no pre-existing CVD at baseline or within the first 2 years of follow-up were included. Four oximetry analysis approaches were applied: desaturation characteristics, time series analysis, power spectral density, and non-linear analysis. Thirty-one resulting oximetry patterns were compared to incident CVD using proportional hazards regression models adjusted for age, race, smoking, BMI, and sex.

RESULTS

There were no associations between OSA oximetry patterns and incident CVD in the total sample or in men. In women, there were some associations between incident CVD and time series analysis (e.g. SpO2 distribution standard deviation, HR 0.81, 95% CI 0.68-0.96, p = 0.014) and power spectral density oximetry patterns (e.g. Full frequency band mean HR 0.75; 95% CI 0.59-0.95; p = 0.015).

CONCLUSIONS

Comprehensive comparison of baseline oximetry patterns in OSA found none were related to development of CVD. There were no standout individual oximetry patterns that appear to be candidates for CVD risk phenotyping in OSA, but some showed marginal relationships with CVD risk in women. Further work is required to understand whether OSA phenotypes can be used to predict susceptibility to cardiovascular disease.

Representation of Race and Sex in Sleep Surgery Studies

OBJECTIVE

Obstructive sleep apnea (OSA) is a highly prevalent disorder with many treatment modalities, including surgical intervention. While OSA is known to be more prevalent in males and Black Americans, the representation of race and sex in sleep surgery studies is unknown. The aim of this systematic review is to assess the race and sex demographics represented in sleep surgery studies relative to known OSA demographics.

DATA SOURCES

PubMed, MEDLINE, and OVID databases.

REVIEW METHODS

A systematic review was conducted to identify studies published between 2016 and 2020 that investigated sleep outcomes following nonnasal surgical intervention for OSA in adults. Pooled racial, ethnic, and sex data of the enrolled subjects in selected studies were analyzed.

RESULTS

The 148 included studies comprised 13,078 patients. Of the 137 studies that reported sex, 84.0% of participants were male, exceeding the population prevalence of OSA in males, which is estimated at 66%. Only 13 studies reported racial/ethnic demographic data. Of these, 87.8% of patients were White. Out of 30 studies of primarily American patients, only 4 reported race demographic data, with an average of 82.8% White participants.

CONCLUSION

There is a racial/ethnic and sex inclusion bias among sleep surgery studies. Future studies should better document the demographics of enrolled participants as well as recruit participants who better represent the demographics of adults with OSA in the general population.

Oximetry Indices in the Management of Sleep Apnea: From Overnight Minimum Saturation to the Novel Hypoxemia Measures

Obstructive sleep apnea (OSA) is a multidimensional disease often underdiagnosed due to the complexity and unavailability of its standard diagnostic method: the polysomnography. Among the alternative abbreviated tests searching for a compromise between simplicity and accurateness, oximetry is probably the most popular. The blood oxygen saturation (SpO₂) signal is characterized by a near-constant profile in healthy subjects breathing normally, while marked drops (desaturations) are linked to respiratory events. Parameterization of the desaturations has led to a great number of indices of severity assessment commonly used to assist in OSA diagnosis. In this chapter, the main methodologies used to characterize the overnight oximetry profile are reviewed, from visual inspection and simple statistics to complex measures involving signal processing and pattern recognition techniques. We focus on the individual performance of each approach, but also on the complementarity among the great amount of indices existing in the state of the art, looking for the most relevant oximetric feature subset. Finally, a quick overview of SpO₂-based deep learning applications for OSA management is carried out, where the raw oximetry signal is analyzed without previous parameterization. Our research allows us to conclude that all the methodologies (conventional, time, frequency, nonlinear, and hypoxemia-based) demonstrate high ability to provide relevant oximetric indices, but only a reduced set provide non-redundant complementary information leading to a significant performance increase. Finally, although oximetry is a robust tool, greater standardization and prospective validation of the measures derived from complex signal processing techniques are still needed to homogenize interpretation and increase generalizability.

Evaluation of Obstructive Sleep Apnea in Female Patients in Primary Care: Time for Improvement?

Obstructive sleep apnea (OSA) has historically been regarded as a male disease. However, there are a number of significant gender-related differences in the symptoms, diagnosis, and consequences of OSA, which seems to be more severe in male than in female patients, although this sex difference decreases with increasing age. Female patients with OSA tend to present nonspecific symptoms, such as insomnia, depressive symptoms, fatigue, morning headache, and nightmares, often resulting in underdiagnosis and undertreatment compared to male patients. Understanding these differences in women is essential for early identification and referral of patients for diagnosis and treatment of OSA.

Longer apneas and hypopneas are associated with greater ultra-short-term HRV in obstructive sleep apnea

Low long-term heart rate variability (HRV), often observed in obstructive sleep apnea (OSA) patients, is a known risk factor for cardiovascular diseases. However, it is unclear how the type or duration of individual respiratory events modulate ultra-short-term HRV and beat-to-beat intervals (RR intervals). We aimed to examine the sex-specific changes in RR interval and ultra-short-term HRV during and after apneas and hypopneas of various durations. Electrocardiography signals, recorded as a part of clinical polysomnography, of 758 patients (396 men) with suspected OSA were analysed retrospectively. Average RR intervals and time-domain HRV parameters were determined during the respiratory event and the 15-s period immediately after the event. Parameters were analysed in three pooled sex-specific subgroups based on the respiratory event duration (10-20 s, 20-30 s, and > 30 s) separately for apneas and hypopneas. We observed that RR intervals shortened after the respiratory events and the magnitude of these changes increased in both sexes as the respiratory event duration increased. Furthermore, ultra-short-term HRV generally increased as the respiratory event duration increased. Apneas caused higher ultra-short-term HRV and a stronger decrease in RR interval compared to hypopneas. In conclusion, the respiratory event type and duration modulate ultra-short-term HRV and RR intervals. Considering HRV and the respiratory event characteristics in the diagnosis of OSA could be useful when assessing the cardiac consequences of OSA in a more detailed manner.

Increased nocturnal arterial pulsation frequencies of obstructive sleep apnoea patients is associated with an increased number of lapses in a psychomotor vigilance task

Objectives

Besides hypoxaemia severity, heart rate variability has been linked to cognitive decline in obstructive sleep apnoea (OSA) patients. Thus, our aim was to examine whether the frequency domain features of a nocturnal photoplethysmogram (PPG) can be linked to poor performance in the psychomotor vigilance task (PVT).

Methods

PPG signals from 567 suspected OSA patients, extracted from Type 1 diagnostic polysomnography, and corresponding results of PVT were retrospectively examined. The frequency content of complete PPGs was determined, and analyses were conducted separately for men (n=327) and women (n=240). Patients were grouped into PVT performance quartiles based on the number of lapses (reaction times ≥500 ms) and within-test variation in reaction times. The best-performing (Q1) and worst-performing (Q4) quartiles were compared due the lack of clinical thresholds in PVT.

Results

We found that the increase in arterial pulsation frequency (APF) in both men and women was associated with a higher number of lapses. Higher APF was also associated with higher within-test variation in men, but not in women. Median APF (β=0.27, p=0.01), time spent under 90% saturation (β=0.05, p<0.01), female sex (β=1.29, p<0.01), older age (β=0.03, p<0.01) and subjective sleepiness (β=0.07, p<0.01) were significant predictors of belonging to Q4 based on lapses. Only female sex (β=0.75, p<0.01) and depression (β=0.91, p<0.02) were significant predictors of belonging to Q4 based on the within-test variation.

Conclusions

In conclusion, increased APF in PPG provides a possible polysomnography indicator for deteriorated vigilance especially in male OSA patients. This finding highlights the connection between cardiorespiratory regulation, vigilance and OSA. However, our results indicate substantial sex-dependent differences that warrant further prospective studies.

Severity of Desaturations Reflects OSA-Related Daytime Sleepiness Better Than AHI

STUDY OBJECTIVES

The aim was to investigate how the severity of apneas, hypopneas, and related desaturations is associated with obstructive sleep apnea (OSA)-related daytime sleepiness.

METHODS

Multiple Sleep Latency Tests and polysomnographic recordings of 362 patients with OSA were retrospectively analyzed and novel diagnostic parameters (eg, obstruction severity and desaturation severity), incorporating severity of apneas, hypopneas, and desaturations, were computed. Conventional statistical analysis and multivariate analyses were utilized to investigate connection of apnea-hypopnea index (AHI), oxygen desaturation index (ODI), conventional hypoxemia parameters, and novel diagnostic parameters with mean daytime sleep latency (MSL).

RESULTS

In the whole population, 10% increase in values of desaturation severity (risk ratio = 2.01, P < .001), obstruction severity (risk ratio = 2.18, P < .001) and time below 90% saturation (t_90%) (risk ratio = 2.05, P < .001) induced significantly higher risk of having mean daytime sleep latency ≤ 5 minutes compared to 10% increase in AHI (risk ratio = 1.63, P < .05). In severe OSA, desaturation severity had significantly (P < .02) stronger negative correlation (ρ = -.489, P < .001) with mean daytime sleep latency compared to AHI (ρ = -.402, P < 0.001) and ODI (ρ = -.393, P < .001). Based on general regression model, desaturation severity and male sex were the most significant factors predicting daytime sleep latency.

CONCLUSIONS

Severity of sleep-related breathing cessations and desaturations is a stronger contributor to daytime sleepiness than AHI or ODI and therefore should be included in the diagnostics and severity assessment of OSA.

CITATION

Kainulainen S, Töyräs J, Oksenberg A, Korkalainen H, Sefa S, Kulkas A, Leppänen T. Severity of desaturations reflects OSA-related daytime sleepiness better than AHI. J Clin Sleep Med. 2019;15(8):1135-1142.

Three Decades of Progress in Sleep Disorders and Sleep Health for Women

Over the past 3 decades, significant strides have been made in the field of sleep medicine for women. The impact of sex and gender on sleep health and sleep disorders received little attention in the early 1990s, but driven by policies ensuring inclusion of women in medical research, more recent studies have identified sex differences in sleep and investigated gender differences in sleep disorders. Nevertheless, disparities remain: diagnosis of sleep disorders, such as obstructive sleep apnea, narcolepsy, and rapid eye movement (REM) sleep behavior disorder are often delayed and underdiagnosed in women. Future research should continue to examine how biological sex and identity across the gender spectrum influence sleep health and sleep disorders, allowing for more personalized health care for all patients.

Smoking and sleep apnea duration mediated the sex difference in daytime sleepiness in OSA patients

PURPOSE

Daytime sleepiness is a common symptom of obstructive sleep apnea (OSA) and is more common in men, but the underlying mechanism remains unclear. The aim of this study was to assess whether or not sex differences in daytime sleepiness persisted after controlling for age and OSA severity and to explore the factors contributing to daytime sleepiness in patients with OSA.

METHODS

A total of 104 pairs of patients with OSA, matched by age and apnea-hypopnea index (AHI), were enrolled in this retrospective study. Demographic data were collected; daytime sleepiness was measured by the Epworth Sleepiness Scale (ESS); and polysomnography (PSG) was performed on each participant. These measurements were compared between sexes, and the factors affecting daytime sleepiness were explored with correlation and multivariate linear regression analyses.

RESULTS

Men had significantly higher ESS scores (p = 0.021) than women. Regarding demographics, BMI, neck/height ratio, and proportion of habitual smoking and alcohol intake were significantly higher in men. Regarding PSG findings, men had more rapid eye movement sleep, a longer mean apnea-hypopnea duration, and a longer mean apnea duration (MAD). Regression analysis showed that two sex-associated variables, habitual smoking (β = 0.189, p = 0.006) and MAD (β = 0.154, p = 0.024), had the strongest association with ESS scores. Further analysis revealed that MAD was significantly influenced by apnea index (β = 0.306, p < 0.001) and sex (β = - 0.193, p = 0.003).

CONCLUSION

The sex difference in daytime sleepiness persists in patients with OSA, even after matching AHI and age. The difference is mediated by sex-specific smoking habits and sex differences in apnea duration.

Obstructive sleep apnea and depression: A systematic review and meta-analysis

INTRODUCTION

The present study aimed to review the association between obstructive sleep apnea (OSA) and depression and compare the prevalence of depression among people with and without OSA.

METHODS

Systematic review and meta-analysis following PRISMA guidelines. We searched for papers published between 1 January 2010 and 20 October 2019 listed on the following databases: Embase, Ovid MEDLINER(R) and PsychINFO. The search terms included a combination of keywords related to sleep apnea and depression. We also completed a manual search of the references listed in the articles retrieved and grouped them according to study design: cross-sectional, case-control and longitudinal. Scale scores were standardised for comparison.

RESULTS

Our search strategy yielded 1158 papers, of which 34 were considered suitable of review and 11 reported data that could be used for meta-analysis. Data from the 6 cross-sectional studies found no compelling evidence of an association between OSA and depression (odds ratio = 1.12, 95 % confidence interval, 95 %CI = 0.78, 1.47), but the meta-analysis of 5 longitudinal studies indicated that people with OSA were at greater risk of developing depression during follow-up than those without OSA (non-specific risk ratio (RR) = 2.18, 95 %CI = 1.47, 2.88), although there was evidence of high study heterogeneity (I² = 72.8 %).

DISCUSSION

The results of this systematic review and meta-analysis of observational studies is consistent with the hypothesis that OSA may increase the risk of depression. Sample characteristics and various methodological issues create uncertainty about the validity and generalizability of these associations.

Polysomnographic characteristics of severe obstructive sleep apnea vary significantly between hypertensive and normotensive patients of both genders

PURPOSE

Hypertension is a common finding in patients with obstructive sleep apnea (OSA), but it has remained unclear whether or not the amount of disturbed breathing and characteristics of individual respiratory events differ between hypertensive and normotensive patients with severe OSA.

METHODS

Full polysomnographic recordings of 323 men and 89 women with severe OSA were analyzed. Differences in the duration of individual respiratory events, total apnea and hypopnea times, and the percentage of disturbed breathing from total sleep time (AHT%) were compared between normotensive and hypertensive patients separately by genders. Furthermore, differences in the respiratory event characteristics were assessed between three AHT% groups (AHT% ≤ 30%, 30% < AHT% ≤ 45%, and AHT% > 45%).

RESULTS

Hypertensive women had lower percentage apnea time (15.2% vs. 18.2%, p = 0.003) and AHT% (33.5% vs. 36.5%, p = 0.021) when compared with normotensive women. However, these differences were not observed between hypertensive and normotensive men. Percentage hypopnea time was higher in hypertensive men (13.5% vs. 11.2%, p = 0.043) but not in women (15.2% vs. 12.2%, p = 0.130) compared with their normotensive counterparts. The variation in AHI explained 60.5% (ρ = 0.778) and 65.0% (ρ = 0.806) of the variation in AHT% in normotensive and hypertensive patients, respectively. However, when AHT% increased, the capability of AHI to explain the variation in AHT% declined.

CONCLUSIONS

There is a major inter- and intra-gender variation in percentage apnea and hypopnea times between hypertensive and normotensive patients with severe OSA. OSA is an important risk factor for hypertension and thus, early detection and phenotyping of OSA would allow timely treatment of patients with the highest risk of hypertension.

Development of methods for sleep disordered breathing to identify phenotypes

Sleep disordered breathing a very common disorder with prevalence rates of up to 49% in large epidemiological studies on subjects older than 40 years. A recent study showed that applying CPAP treatment to patients with sleep disordered breathing recruited by their number of apnea and hypopnea events alone, does improve sleepiness but does not improve overall cardiovascular mortality. Based on older large studies however it is knownthat sleep disordered breathing is a cardiovascular risk and that treatment lowers mortality and morbidity. These results appear to be contradictory. However, they might be explained if patient population investigated are carefully reviewed further, and if sleep apnea severity metrics are reconsidered. According to this, it appears that studies speak of different populations. Whereas epidemiological studies use sampled subjects willing to participate, earlier studies used patients contacting a sleep center with complaints and symptoms. In this paper two studies are presented with an assessment of anatomical metrics for upper airway morphology in order to derive parameters for better prediction. Different phenotypes can explain why some people benefit from treatment and others do not benefit equally. Therefore more than just counting apnea and hypopnea events is needed in order to identify patients at risk and patients who have a lower risk when treated. This will require large data set evaluations with hard outcome data.

Gender differences in severity of desaturation events following hypopnea and obstructive apnea events in adults during sleep

OBJECTIVE

Severity estimation of obstructive sleep apnea (OSA) is currently based on the apnea-hypopnea index (AHI), which ignores individual breathing cessation event characteristics. Gender differences in the relationship between the breathing cessation event duration and the related desaturation event severity could mean that the severity of OSA is different in males and females despite a similar AHI. The aim of this work was to evaluate gender differences in the severity of peripheral oxygen desaturation events following obstructive apneas or hypopneas.

APPROACH

Type I polysomnographic recordings of 220 males and 175 females were analyzed. The obstructive apnea and hypopnea events were divided into eight different durational categories from 10 s to 45 s with 5 s interval and  >45 s. The desaturation event severities following obstructive apneas or hypopneas were compared between genders within these durational categories.

MAIN RESULTS

Desaturations following obstructive apneas with a duration of 30-45 s were substantially more severe (p  <  0.05) in females compared to males. In contrast, areas of desaturations following hypopneas (with related hypopnea event durations  ⩽30 s) were smaller (p  <  0.05) in females compared to males. In general, desaturation events following obstructive apneas were more severe compared to desaturations following hypopneas and the increase in the duration of obstructive apnea and hypopnea events led to an increase in the related desaturation severity in both genders.

SIGNIFICANCE

We found gender differences in the desaturation event severities following obstructive apneas and hypopneas. The results indicate that in females longer obstructive apneas (>30 s) could be more detrimental compared to those of males. As severe health consequences are related to the desaturation severity these aspects should be considered when estimating the severity of OSA.

Peri-apneic hemodynamic reactions in obstructive sleep apnea

Obstructive sleep apnea (OSA) increases cardiovascular morbidity and mortality. Little is known on acute peri-apneic hemodynamic alterations due to apneas. We assessed these rapid changes and how duration of apnea might contribute to them. Eight patients with severe OSA were studied with polysomnography including continuous blood pressure monitoring. Peri-apneic hemodynamic alterations, heart rate, blood pressure, stroke volume, cardiac output and peripheral resistance, were assessed in short (<20s) and long (>27s) apneas. Systolic and diastolic blood pressure along with heart rate elevated significantly in both apneas. These changes occurred within first 10 beats immediately after apnea. In contrast to short apneas long apneas caused sudden increase of 0.7l in cardiac output. Acute and pronounced peri-apneic hemodynamic alterations were seen during both short and long apneas. These described rapid hemodynamic changes might escape autoregulatory mechanisms of several organs, thus making OSA patients vulnerable to acute cardiovascular events.