The hypoxic burden of sleep apnoea predicts cardiovascular disease-related mortality: the Osteoporotic Fractures in Men Study and the Sleep Heart Health Study

Obstructive Sleep Apnea and Longitudinal Changes in Interstitial Lung Imaging and Lung Function: The MESA Study

Rationale: Obstructive sleep apnea (OSA) has been hypothesized to be a risk factor in interstitial lung disease (ILD) and is associated with radiological markers that may represent the earlier stages of ILD. Prior studies have been limited by their cross-sectional design and potential confounding by body habitus. Objectives: To test the hypothesis that OSA severity is associated with more high-attenuation areas (HAAs) on computed tomography and worse lung function over time among older community-dwelling adults. Methods: We used data from participants in the MESA (Multi-Ethnic Study of Atherosclerosis) who had apnea-hypopnea index (AHI) measured from polysomnography (2010-2013), high attenuation areas (HAAs, -600 to -250 Hounsfield units, n = 784), assessments from exams 5 (2010-2012) and 6 (2016-2018) full-lung computed tomography scans, and spirometry assessments (n = 677). Linear mixed-effects models with random intercept were used to examine associations of OSA severity (i.e., AHI and hypoxic burden) with changes in HAAs, total lung volumes, and forced vital capacity (FVC) between exams 5 and 6. Potential confounders were adjusted for in the model, including age, sex, smoking history, height, and weight. Results: Among those with a higher AHI there were more men and a higher body mass index. Participants with AHI ⩾ 15 events/h and in the highest hypoxic burden quartile each had increases in HAAs of 11.30% (95% confidence interval [CI], 3.74-19.35%) and 9.85% (95% CI, 1.40-19.01%) per 10 years, respectively. There was a more rapid decline in total lung volumes imaged and FVC among those with AHI ⩾ 15 events/h of 220.2 ml (95% CI, 47.8-392.5 ml) and 3.63% (95% CI, 0.43-6.83%) per 10 years, respectively. Conclusions: A greater burden of hypoxia related to obstructive events during sleep was associated with increased lung densities over time and a more rapid decline in lung volumes regardless of body habitus. Our findings suggest OSA may be a contributing factor in the early stages of ILD.

Transvenous phrenic nerve stimulation for the treatment of central sleep apnea reduces episodic hypoxemic burden

STUDY OBJECTIVES

To determine the effect of transvenous phrenic nerve stimulation (TPNS) on the composition of the nocturnal hypoxemic burden in patients with CSA.

METHODS

We analysed oximetry data from baseline and follow-up overnight polysomnograms (PSG) in 134 CSA patients with implanted TPNS randomised (1:1) to neurostimulation (treatment group; TPNS on) or no stimulation (control group; TPNS off) from the remedē System Pivotal Trial. The hypoxemic burden was quantified using a battery of metrics, including the oxygen desaturation index (ODI), the relative sleep time spent below 90% SpO2 (T90) due to acute episodic desaturations (T90_desat) and due to non-specific and non-cyclic drifts of SpO2 (T90_non-specific). Mean change from baseline is provided.

RESULTS

TPNS titrated to reduce respiratory events significantly reduced the ODI in the treatment group by -15.85 h^-1 ± 1.99 compared to the control group, which increased 1.32 h^-1 ± 1.85 (p 〈0001) and shortened the relative T90 duration by -3.81 percentage points ± 1.23 vs. 0.49 percentage points ± 1.14 increase (p = 0.012). This shortening of T90 was primarily accomplished by reducing the brief cyclic desaturations (T90_desaturation: -4.32 percentage points ± 0.98 vs. 0.52 percentage points ± 0.91, p = 0.0004) while notable non-specific drifts in SpO₂ remained unchanged (T90_non-specific: 0.18 percentage points ± 0.62 vs. -0.13 percentage points ± 0.57, p = 0.72).

CONCLUSIONS

TPNS appears to significantly reduce the nocturnal hypoxemic burden due to sleep-disordered breathing, but a considerable nocturnal hypoxemic burden from other sources remains. Further investigations are warranted to identify the best strategy to reduce the nocturnal hypoxemic burden beyond preventing respiratory events.

Comorbidity Profile and Predictors of Obstructive Sleep Apnea Severity and Mortality in Non-Obese Obstructive Sleep Apnea Patients

Backgrounds and Objectives: Obstructive sleep apnea (OSA) is associated with increased morbidity and mortality. OSA is an independent risk factor for many different conditions, especially cardiovascular diseases. The purpose of this study was to ascertain the comorbidity profile of non-obese patients with newly diagnosed OSA and evaluate the risk for cardiovascular disease and mortality. The present study also aimed to establish predictors for OSA severity. Materials and Methods: This study included 138 newly diagnosed patients who underwent polysomnographic analysis. The 10-year risk for cardiovascular disease was assessed using a newly validated prediction model: Systematic Coronary Risk Evaluation (SCORE-2). In addition, the Charlson Comorbidity Index (CCI) was assessed as a widely-used example of a mortality comorbidity index. Results: The study population included 138 patients: 86 males and 52 females. Patients were stratified, according to AHI (apnea/hypopnea index), into four groups: 33 patients had mild OSA (5 ≤ AHI < 15), 33 patients had moderate OSA (15 ≤ AHI < 30), 31 patients had severe OSA (AHI ≥ 30), and 41 individuals had AHI < 5, which were a part of the control group. SCORE-2 increased in line with OSA severity and was higher in OSA groups compared to the control group (H = 29.913; DF = 3; p < 0.001). Charlson Index was significantly higher in OSA patients compared to controls (p = 0.001), with a higher prevalence of total comorbidities in the OSA group of patients. Furthermore, CCI 10-year survival score was significantly lower in the OSA group, suggesting a shorter survival of those patients with a more severe form of OSA. We also examined the prediction model for OSA severity. Conclusions: Determining the comorbidity profile and estimation of the 10-year risk score of OSA patients could be used to classify these patients into various mortality risk categories and, according to that, provide them with adequate treatment.

High night-to-night variability in sleep apnea severity is associated with uncontrolled hypertension

Obstructive sleep apnea (OSA) severity can vary markedly from night-to-night. However, the impact of night-to-night variability in OSA severity on key cardiovascular outcomes such as hypertension is unknown. Thus, the primary aim of this study is to determine the effects of night-to-night variability in OSA severity on hypertension likelihood. This study uses in-home monitoring of 15,526 adults with ~180 nights per participant with an under-mattress sleep sensor device, plus ~30 repeat blood pressure measures. OSA severity is defined from the mean estimated apnea-hypopnoea index (AHI) over the ~6-month recording period for each participant. Night-to-night variability in severity is determined from the standard deviation of the estimated AHI across recording nights. Uncontrolled hypertension is defined as mean systolic blood pressure ≥140 mmHg and/or mean diastolic blood pressure ≥90 mmHg. Regression analyses are performed adjusted for age, sex, and body mass index. A total of 12,287 participants (12% female) are included in the analyses. Participants in the highest night-to-night variability quartile within each OSA severity category, have a 50-70% increase in uncontrolled hypertension likelihood versus the lowest variability quartile, independent of OSA severity. This study demonstrates that high night-to-night variability in OSA severity is a predictor of uncontrolled hypertension, independent of OSA severity. These findings have important implications for the identification of which OSA patients are most at risk of cardiovascular harm.

Obstructive sleep apnea is not associated with diabetic retinopathy in diabetes: a prospective case-control study

PURPOSE

Diabetic retinopathy (DR) is the most common ocular complication of type 2 diabetes mellitus (T2D) and is associated with diabetes duration, glycemic control, and hypertension (HTN). Obstructive sleep apnea (OSA) is frequent in T2D and is associated with poor glycemic control. However, it is unclear if there is an association between OSA and DR. This study aimed to assess whether or not the presence of OSA in patients with T2D was associated with DR.

METHODS

In this prospective case-control study, consecutive patients with DM attending the ophthalmology clinics were recruited to include patients with DR (cases) and without DR (controls). OSA was diagnosed by attended polysomnography (PSG). Blood pressure and a fasting morning blood sample, including glycosylated hemoglobin (HbA1c), were recorded. Patients were matched for age, body mass index (BMI), gender, and T2D duration.

RESULTS

Thirty diabetic patients with DR were matched with 30 controls. In all patients, the prevalence of moderate-to-severe OSA was 57%. In the logistic regression analysis, DR was associated with increased HbA1c (OR 2.63, 95% CI 1.35-5.16, p = 0.004) but not with any PSG parameter. In the DR group, PSG parameters were not associated with the severity of ocular disease (non-proliferative, proliferative, presence/absence of macular edema). The proliferative aspect of DR was correlated with age (p = 0.017). DR occurred more frequently in uncontrolled diabetes compared to well-controlled diabetes (80% vs 38%, p = 0.029).

CONCLUSIONS

In patients with T2D, the presence of DR is not associated with OSA, but with poorly controlled T2D.

Respiratory effort during sleep and prevalent hypertension in obstructive sleep apnoea

BACKGROUND

Mechanisms underlying blood pressure changes in obstructive sleep apnoea (OSA) are incompletely understood. Increased respiratory effort is one of the main features of OSA and is associated with sympathetic overactivity, leading to increased vascular wall stiffness and remodelling. This study investigated associations between a new measure of respiratory effort (percentage of total sleep time spent with increased respiratory effort based on measurement of mandibular jaw movements (MJM): REMOV, %TST) and prevalent hypertension in adults referred for evaluation of suspected OSA.

METHODS

A machine learning model was built to predict hypertension from clinical data, conventional polysomnography (PSG) indices and MJM-derived parameters (including REMOV). The model was evaluated in a training subset and a test subset.

RESULTS

The analysis included 1127 patients: 901 (80%) in the training subset and 226 (20%) in the test subset. The prevalence of hypertension was 31% and 30%, respectively, in the training and test subsets. A risk stratification model based on 18 input features including REMOV had good accuracy for predicting prevalent hypertension (sensitivity 0.75 and specificity 0.83). Using the Shapley additive explanation method, REMOV was the best predictor of hypertension after clinical risk factors (age, sex, body mass index and neck circumference) and time with oxygen saturation <90%, ahead of standard PSG metrics (including the apnoea-hypopnoea index and oxygen desaturation index).

CONCLUSION

The proportion of sleep time spent with increased respiratory effort automatically derived from MJM was identified as a potential new reliable metric to predict prevalent hypertension in patients with OSA.

Nocturnal hypoxia indexes are associated with left ventricular remodeling and diastolic dysfunction in obstructive sleep apnea patients

BACKGROUND AND OBJECTIVE

Obstructive sleep apnea (OSA) is associated with heart derangements detected at echocardiography as higher left ventricular mass index (LVMI), higher left ventricular end-diastolic diameter, lower left ventricular ejection fraction (LVEF), and impaired diastolic function. However, the currently used parameter to define OSA diagnosis and severity, the apnea/hypopnea index (AHI), poorly predicts cardiovascular damage, cardiovascular events, and mortality. Our study aimed to assess if other polygraphic indices of OSA presence and severity, in addition to AHI, might better predict echocardiographic cardiac remodeling.

METHODS AND RESULTS

We enrolled two cohorts of individuals referred for suspected OSA to the outpatient facilities of the IRCCS Istituto Auxologico Italiano, Milano, and of the Clinica Medica 3, Padova. All patients underwent home sleep apnea testing and echocardiography. Based on the AHI the cohort was divided into no-OSA (AHI<15 events/hour) and moderate-severe OSA (AHI≥15 events/hour). We recruited 162 patients and found that compared to patients with no-OSA, those with moderate-severe OSA showed higher LV remodeling [left ventricular end-diastolic volume (LVEDV) 48.4 ± 11.5 ml/m2 vs. 54.1 ± 14.0 ml/m2, respectively, p = 0.005] and lower LVEF (65.3 ± 5.8% vs. 61.6 ± 7.8%, respectively, p = 0.002), whereas we could not find any difference in LVMI and early and late ventricular filling velocity ratio (E/A). At multivariate linear regression analysis two polygraphic hypoxic burden-related markers were independent predictors of LVEDV and E/A, i.e., the percentage of time with O2 saturation below 90% (β = 0.222) and ODI (β = -0.422), respectively.

CONCLUSIONS

Our study shows that nocturnal hypoxia-related indexes were associated with left ventricular remodeling and diastolic dysfunction in OSA patients.

Effects of the combination of atomoxetine and oxybutynin in Japanese patients with obstructive sleep apnoea: A randomized controlled crossover trial

BACKGROUND AND OBJECTIVE

The possibility of combination therapy with atomoxetine (ATO) and oxybutynin (OXY) has been suggested for obstructive sleep apnoea (OSA). However, the effectiveness of this treatment remains uninvestigated in Japanese OSA patients. Therefore, we performed a randomized, crossover, phase II, single-centre prospective trial to examine the effects of ATO-OXY therapy in Japanese OSA patients.

METHODS

In total, 17 OSA patients participated in this study. The effects of one night of 80-mg ATO plus 5-mg OXY administration were compared with those of no medication administered before sleep. The primary and secondary outcomes comprised the apnoea-hypopnoea index (AHI) and nadir SpO₂ , SpO₂ drop time and sleep architecture, respectively. The safety endpoints included drug side effects and adverse events.

RESULTS

The values of AHI, nadir SpO₂ , 3% oxygen desaturation index (ODI), 4% ODI, and SpO₂ drop time of <90% did not significantly differ between patients receiving ATO-OXY administration and no medication. Sleep architecture exhibited a significant change: ATO-OXY increased sleep stage N1 (p < 0.0001) and decreased stage N2 (p = 0.03), rapid eye movement (p < 0.0001) and sleep efficiency (p = 0.02). However, the subanalysis demonstrated an obvious decrease in AHI in five responder patients. Total sleep time and basal sleep efficiency tended to be lower in the responders compared with nonresponders (p = 0.065). No patients experienced severe adverse events or side effects.

CONCLUSION

Overall, ATO-OXY therapy does not reduce AHI in Japanese OSA patients, although AHI was decreased in a proportion of patients. Future studies for identifying treatment response group characteristics are warranted.

Implication of a novel measure of obstructive sleep apnea severity for cardiovascular morbidity

OBJECTIVE

To evaluate the association between cardiovascular morbidity and obstructive sleep apnea (OSA) severity quantified using the sleep breathing impairment index (SBII), a novel measure that captures both respiratory events and event-associated hypoxia.

PATIENTS AND METHODS

This retrospective follow-up study included 737 participants with OSA who were diagnosed based on an apnea-hypopnea index of >5/h in polysomnography from January 1, 2012 to December 31, 2015. Data on baseline clinical characteristics and polysomnography parameters were collected. SBII was determined as the sum of products of respiratory events and event-related desaturation areas, and was categorized based on its quintiles. The outcomes were any hospital admission for cardiovascular diseases, including coronary heart disease, stroke, peripheral vascular disease, or heart failure after the diagnosis of OSA. Logistic regression models were constructed to estimate the potential association between SBII and cardiovascular morbidity after adjusting for confounders.

RESULTS

A total of 60 cardiovascular events were recorded. Compared with the first quintile of SBII, the odds ratio (95% confidence interval [CI]) of cardiovascular morbidity for the second, third, and fourth quintiles were 4.01 (95% CI, 1.22-13.24), 3.91 (95% CI, 1.05-14.53), and 7.57 (95% CI, 1.70-33.68) after adjusting for covariables, including anthropometric variables, medical conditions, and sleep parameters.

CONCLUSION

In patients with OSA, higher SBII was associated with an increased cardiovascular risk. These findings suggest that a more comprehensive measure, such as SBII incorporating the respiratory event and related hypoxia during sleep, may better capture the disease burden and reflect the OSA-associated adverse outcomes.

[Effect of Objective Daytime Sleepiness on Heart Rate Variability in Patients With Obstructive Sleep Apnea]

Objective

Excessive daytime sleepiness (EDS) is associated with cardiovascular events in patients with obstructive sleep apnea (OSA). Our study explored the correlation between objective daytime sleepiness assessed with daytime multiple sleep latency tests (MSLT) and heart rate variability (HRV) in OSA patients. The results may provide insight into possible mechanisms underlying increased risk of cardiovascular events in patients with OSA.

Methods

A retrospective analysis was conducted with the data of 139 patients with OSA and 35 patients with primary snoring. All subjects underwent polysomnography (PSG) and MSLT at West China Hospital between January 2019 and May 2022. We used mean sleep latency (MSL) to measure the severity of EDS and to categorize OSA patients into three groups, severe EDS, light EDS, and non-EDS, with MSL of less than 5 minutes, 5 to 10 minutes, and greater than 10 minutes as the respective defining criteria for classification. A comparison of sleep structure, clinical characteristics, and HRV parameters was performed in order to evaluate the difference between OSA subgroups with varying levels of objective EDS and the primary snoring group. In addition, we also analyzed the correlation between MSL and HRV parameters.

Results

Severe EDS patients had higher values of standard deviation of all N-N intervals (SDNN), total spectral power (TOT), and low-frequency power (LF) as compared to non-EDS patients, which was indicative of sympathetic stimulation ( P<0.05). Additionally, high-frequency power (HF) was also higher in severe EDS patients, which indicated decreased parasympathetic drive. A significantly positive correlation was found between MSL and the values of SDNN, TOT, LF, and HF in OSA patients.

Conclusion

OSA patients with objective EDS have elevated sympathetic drive and decreased parasympathetic drive. A positive correlation was found between this change in neural activity and the shortening of MSL.

Exercise capacity remains supernormal, though mildly reduced in middle-aged military personnel with Moderate to Severe Obstructive Sleep Apnea

INTRODUCTION

The relationship between moderate to severe OSA and exercise capacity remains unclear. Prior studies showing a reduction in VO₂ max in this population have mostly involved middle-aged, overweight patients. We aimed to study this relationship in a similarly aged population of military personnel with previously undiagnosed moderate to severe OSA.

METHODS

We studied late-career male military personnel who underwent CPET and polysomnography (PSG). Patients were categorized either into an OSA group (apnea-hypopnea index (AHI) ≥ 15 events/h) or a control group (AHI < 15 events/h). VO₂ max was compared between groups.

RESULTS

170 male military personnel met criteria for the study. Mean AHI was 29.0/h in the OSA group (n = 58) versus 7.4/h in the controls (n = 112) while SpO₂ nadir was slightly lower (86.0% vs. 89.0%). Patients were of similar age (53.1 vs. 53.7 years), and BMI was slightly higher in the OSA group (27.5 kg/m² vs. 26.3 kg/m²). Percent-predicted VO₂ max was supernormal in both groups, though it was comparatively lower in the OSA group (117% vs. 125%; p < 0.001).

CONCLUSIONS

Military personnel with moderate to severe OSA were able to achieve supernormal VO₂ max values, yet had an 8% decrement in exercise capacity compared to controls. These findings suggest that OSA without significant hypoxemia may not significantly influence exercise capacity. It remains likely that the effects of untreated OSA on exercise capacity are complex and are affected by several variables including BMI, degree of associated hypoxemia, and regularity of exercise. Statistically lower VO₂ max noted in this study may suggest that untreated OSA in less fit populations may lead to significant decrements in exercise capacity.

Impact of reboxetine plus oxybutynin treatment for obstructive sleep apnea on cardiovascular autonomic modulation

The combination of noradrenergic (reboxetine) plus antimuscarinic (oxybutynin) drugs (reb-oxy) reduced obstructive sleep apnea (OSA) severity but no data are available on its effects on cardiac autonomic modulation. We sought to evaluate the impact of 1-week reb-oxy treatment on cardiovascular autonomic control in OSA patients. OSA patients were randomized to a double-blind, crossover trial comparing 4 mg reboxetine plus 5 mg oxybutynin to a placebo for OSA treatment. Heart rate (HR) variability (HRV), ambulatory blood pressure (BP) monitoring (ABPM) over 24 h baseline and after treatment were performed. Baroreflex sensitivity was tested over beat-to-beat BP recordings. 16 subjects with (median [interquartile range]) age 57 [51-61] years and body mass index 30 [26-36]kg/m² completed the study. The median nocturnal HR was 65 [60-69] bpm at baseline and increased to 69 [64-77] bpm on reb-oxy vs 66 [59-70] bpm on placebo (p = 0.02). The mean 24 h HR from ABPM was not different among treatment groups. Reb-oxy administration was not associated with any modification in HRV or BP. Reb-oxy increased the baroreflex sensitivity and did not induce orthostatic hypotension. In conclusion, administration of reb-oxy did not induce clinically relevant sympathetic overactivity over 1-week and, together with a reduction in OSA severity, it improved the baroreflex function.

Sleep Irregularity and Subclinical Markers of Cardiovascular Disease: The Multi-Ethnic Study of Atherosclerosis

Background Sleep irregularity has been linked to incident cardiovascular disease. Less is known about associations of sleep regularity with atherosclerosis. We examined cross-sectional associations of actigraphy-assessed sleep duration and sleep timing regularity with subclinical atherosclerosis in the community-based MESA (Multi-Ethnic Study of Atherosclerosis). Methods and Results MESA Sleep Ancillary Study participants (N=2032; mean age, 68.6±9.2 years; 37.9% White) completed 7-day wrist actigraphy. Participants underwent assessments of coronary artery calcium, carotid plaque presence, carotid intima-media thickness, and the ankle-brachial index. Sleep regularity was quantified by the 7-day with-in person SD of sleep duration and sleep onset timing. Relative risk regression models were used to calculate prevalence ratios and 95% CIs. Models are adjusted for demographics, cardiovascular disease risk factors, and other objectively assessed sleep characteristics including obstructive sleep apnea, sleep duration, and sleep fragmentation. After adjustment, compared with participants with more regular sleep durations (SD ≤60 minutes), participants with greater sleep duration irregularity (SD >120 minutes) were more likely to have high coronary artery calcium burden (>300; prevalence ratio, 1.33 [95% CI, 1.03-1.71]) and abnormal ankle-brachial index (<0.9; prevalence ratio, 1.75 [95% CI, 1.03-2.95]). Compared with participants with more regular sleep timing (SD ≤30 minutes), participants with irregular sleep timing (SD >90 minutes) were more likely to have high coronary artery calcium burden (prevalence ratio, 1.39 [95% CI, 1.07-1.82]). Associations persisted after adjustment for cardiovascular disease risk factors and average sleep duration, obstructive sleep apnea, and sleep fragmentation. Conclusions Sleep irregularity, particularly sleep duration irregularity, was associated with several measures of subclinical atherosclerosis. Sleep regularity may be a modifiable target for reducing atherosclerosis risk. Future investigation into cardiovascular risk reduction interventions targeting sleep irregularity may be warranted.

Prevalence of sleep apnoea in patients with type 1 diabetes and its association with comorbidities and diabetic complications: A French nationwide prospective study

AIM

To investigate sleep apnoea prevalence, factors influencing severity, and associations between sleep apnoea severity and micro-/macrovascular complications in a large population of patients with type 1 diabetes.

MATERIALS AND METHODS

This French multicentre prospective cohort study was conducted between July 2016 and June 2020. Adults with type 1 diabetes using an insulin pump were eligible. Home care provider nurses collected demographic and clinical data and set up oximetry to determine the oxygen desaturation index (ODI). No, mild-moderate and severe sleep apnoea were defined as ODI <15 events/h, 15 to <30 events/h and ≥30 events/h, respectively. Univariate and multivariate analyses were performed to identify factors associated with sleep apnoea, and associations between sleep apnoea severity and micro-/macrovascular complications were determined using logistic regression.

RESULTS

Of 769 participants, 12.4% and 3.4% had mild-to-moderate or severe sleep apnoea, respectively. Factors significantly associated with sleep apnoea on multivariate analysis were age, sex, body mass index (BMI) and hypertension. After adjustment for age, sex and BMI, presence of severe sleep apnoea was significantly associated with macrovascular complications (odds ratio vs. no sleep apnoea: 3.96 [95% confidence interval 1.43-11.11]; P < 0.01), while mild-to-moderate sleep apnoea was significantly associated with presence of diabetic retinopathy (odds ratio 2.09 [95% confidence interval 1.10-3.74]; P < 0.01).

CONCLUSION

Sleep apnoea is a significant comorbidity in patients with type 1 diabetes, especially with respect to diabetic complications. This highlights the need for sleep apnoea screening and management in these individuals.

Prognostic Implications of OSA in Acute Coronary Syndrome by Obesity Status

BACKGROUND

A close relationship exists between OSA and obesity. The impact of obesity on the prognostic significance of OSA in patients with acute coronary syndrome (ACS) remains unclear.

RESEARCH QUESTION

Do the effects of OSA on subsequent cardiovascular events in patients with ACS vary with obesity status?

STUDY DESIGN AND METHODS

This is a prospective cohort study. Patients 18 to 85 years of age and hospitalized for ACS were consecutively enrolled and underwent portable sleep monitoring after clinical stabilization. OSA was defined as an apnea hypopnea index ≥ 15 events/h. The primary end point was major adverse cardiovascular and cerebrovascular event (MACCE), including cardiovascular death, hospitalization for ACS, stroke, ischemia-driven revascularization, or hospitalization for heart failure.

RESULTS

Among 1,920 patients enrolled (84.5% men; mean age ± SD, 56.4 ± 10.5 years), 1,013 (52.8%) had OSA, and 718 (37.4%) were obese (BMI ≥ 28 kg/m²). During 2.9 years (1.5, 3.6) follow up, the incidence of MACCE was significantly higher in patients with obesity than in patients without obesity (hazard ratio [HR], 1.29; 95% CI, 1.06-1.58; P = .013). Although the prevalence of OSA was lower in patients without obesity than in those with obesity (43.9% vs 67.5%, P < .001), OSA independently predicted the incidence of MACCE only in patients without obesity (adjusted HR, 1.34; 95% CI, 1.03-1.75; P = .03), but not in patients with obesity (adjusted HR, 1.10; 95% CI, 0.78-1.55; P = .58). No significant interaction between obesity and OSA was noted (P for interaction = .35). The incremental risk associated with OSA in patients without obesity might be explained by more hospitalization for ACS and ischemia-driven revascularization.

INTERPRETATION

For patients with ACS, OSA was independently associated with an increased risk of subsequent events, particularly among patients without obesity. These findings highlight the importance of identifying OSA in nonobese patients with ACS.

CLINICAL TRIAL REGISTRATION

ClinicalTrials.gov; No.: NCT03362385; URL: www.

CLINICALTRIALS

gov.

Depression with obstructive sleep apnea lead to high cardiovascular disease morbidity/all-cause mortality: Findings from the SHHS cohort

The aim of this study is to explore the association between depression and obstructive sleep apnea, and cardiovascular disease morbidity/all-cause mortality using Sleep Heart Health Study data. This post hoc analysis of a prospective study used patient data from the Sleep Heart Health Study conducted between 1995 and 1998. The association between depression and obstructive sleep apnea, and cardiovascular disease morbidity/all-cause mortality was explored using multivariable Cox proportional hazard models. A total of 4918 participants, 656 (13.3%) with obstructive sleep apnea (obstructive sleep apnea group), 1614 (32.8%) with depression (depression group), 482 (9.8%) with depression and obstructive sleep apnea (depression and obstructive sleep apnea group), and 2166 (44%) with neither obstructive sleep apnea nor depression (health group), were included. The incidence of cardiovascular disease was 24.5%, 31.0%, 31.6% and 41.7% for healthy, depression, obstructive sleep apnea, and depression and obstructive sleep apnea groups, respectively. The risk of cardiovascular disease in depression and obstructive sleep apnea participants was increased compared with that in healthy participants, which was consistent across various definitions of obstructive sleep apnea (hazard ratio [95% confidence interval]: 1.24 [1.06-1.47]; 1.25 [1.05-1.49]; 1.28 [1.06-1.54]; 1.55 [1.22-1.96] for apnea-hypopnea index ≥ 10 per hr, 15 per hr, 20 per hr, 30 per hr, respectively). The risk of all-cause mortality was increased in the depression and obstructive sleep apnea participants (hazard ratio: 1.46; 95% confidence interval: 1.07-1.99) compared with that in healthy participants when the definition of obstructive sleep apnea was apnea-hypopnea index ≥ 30. Participants with depression and obstructive sleep apnea might be at a greater risk of cardiovascular disease, and those with higher apnea-hypopnea index might be at a greater risk of all-cause mortality.

Influence of obstructive sleep apnea syndrome on the contralateral optic nerve in patients with unilateral nonarteritic anterior ischemic optic neuropathy

STUDY OBJECTIVES

The aim was to quantitatively evaluate the influence of obstructive sleep apnea syndrome (OSAS) on the morphology and function of the contralateral optic nerve in patients with unilateral nonarteritic anterior ischemic optic neuropathy (NAION).

METHODS

Fifty patients with unilateral NAION were divided into non-OSAS (n = 16), mild OSAS (n = 15), and moderate-severe OSAS (n = 19) groups based on their apnea-hypopnea index (AHI) scores. Systemic and ocular characteristics were compared between these groups. Spearman correlation and multiple linear regression analyses were used to determine the independent factors that most influenced the thickness of the peripapillary retinal nerve fiber layer (pRNFL).

RESULTS

Body mass index and hypertension occurrence were higher in the moderate-severe OSAS group than in the non-OSAS group. Temporal pRNFL was thinner in the moderate-severe group than in the mild and non-OSAS groups, whereas no difference was found between the mild and non-OSAS groups. Spearman correlation showed that the AHI (r = -.469, P = .001) and the percentage of total sleep time with oxygen saturation < 90% (T90%; r = -.477, P = .001) correlated with temporal pRNFL thickness. Multiple linear regression showed that the AHI was negatively associated with temporal pRNFL thickness (β = -0.573, P = .003).

CONCLUSIONS

OSAS may cause subclinical temporal pRNFL thinning in the contralateral optic nerve among patients with unilateral NAION without any significant change in visual function. Advanced optic nerve observation and intervention may be warranted in patients with moderate-severe OSAS.

CITATION

Li X, Zhang Y, Guo T, et al. Influence of obstructive sleep apnea syndrome on the contralateral optic nerve in patients with unilateral nonarteritic anterior ischemic optic neuropathy. J Clin Sleep Med. 2023;19(2):347-353.

Effects of the combination of novel eye mask sleep position therapy device and oral appliance on positional OSA: A multi-arm, parallel-group randomized controlled trial

OBJECTIVES

We explored whether a new combination of eye mask sleep position therapy (SPT) and oral appliance therapy (OAT) was more effective at treating positional obstructive sleep apnea (POSA) than was the use of either device alone.

METHODS

In this randomized controlled trial, 60 POSA subjects diagnosed by standard polysomnography (PSG) were divided into three groups (ratio 1:1:1): SPT, OAT, and SPT combined with OAT (SOT). Participants underwent hospital-based follow-ups during months 1 and 6 after beginning treatment. The primary outcome was the decline in the apnea hypopnea index (AHI) at month 6. The secondary outcomes were changes in oxygen-derived parameters and the curative effect at month 6.

RESULTS

After 6 months of treatment, PSG showed that SPT, OAT, and SOT all improved the AHI and oxygen-derived parameters. The AHI decline was significantly better in the SOT group than in the OAT or SPT group (71.58% [50.56-84.84%] for SOT, 44.42% [21.23-67.52%] for OAT, and 33.24% [19.03-54.62%] for SPT at 6 months) (P = 0.018 and P < 0.001 for the comparisons of SOT with OAT and SOT with SPT, respectively). In terms of oxygen-derived parameters, only the sleep apnea-specific hypoxic burden (SASHB) improved more in the SOT group (76.89% [57.43-85.91%]) than in the other groups (44.73% [32.38-72.69%] for OAT and 41.82% [15.40-65.24%] for SPT, P = 0.002 and P < 0.001 for the comparisons of SOT with OAT and SOT with SPT, respectively). The efficacies of SPT, OAT, and SOT were 36.84%, 50%, and 80% at 6 months; the SOT group evidenced the highest value (rate ratio [95% confidence interval] 1.78 (1.05-3.03), P = 0.048 and 2.17 (1.16-4.07), P = 0.010, for the comparisons of SOT with OAT and SOT with SPT, respectively).

CONCLUSION

The combination of SPT and OAT was better than either treatment alone and may represent a good option for the treatment of POSA.

TRIAL REGISTRATION

Chinese Clinical Trial Registry; URL: http://www.chictr.org.cn/showproj.aspx?proj=42,852; No. ChiCTR1900025584.

Implication of prolonged nocturnal hypoxemia and obstructive sleep apnea for pulmonary hemodynamics in patients being evaluated for pulmonary hypertension: a retrospective study

STUDY OBJECTIVES

The unique pathophysiologic contributions of obstructive sleep apnea (OSA) toward pulmonary hypertension and right ventricular (RV) dysfunction still represent an understudied area. We aimed to investigate the impacts of various respiratory parameters on pulmonary hemodynamics and RV performance in OSA.

METHODS

Data of consecutive patients with OSA who completed right heart catheterization for evaluation of pulmonary hemodynamics were retrospectively reviewed and analyzed. Univariable and multivariable regression analyses were used to determine the significant respiratory parameter associated with right heart catheterization metrics.

RESULTS

Of 205 patients with OSA (43.4% male), 134 (65.4%) had pulmonary hypertension. Among various sleep parameters, the time percentage spent with SpO2 below 90% (T90) was the sole and the strongest independent factor associated with mean pulmonary artery pressure (mPAP) (β = 0.467, P < .001), pulmonary vascular resistance (PVR) (β = 0.433, P < .001), and RV stroke work index (RVSWI) (β = 0.338, P < .001). For every 5-unit increase in T90, there was approximately 36% greater risk of mPAP ≥ 25 mmHg (odds ratio [OR] 1.36, 95% confidence interval [CI] 1.16-1.59, P < .001), and 45% greater risk of PVR > 3 Woods units (OR 1.45, 95% CI 1.21-1.74, P < .001), respectively. T90 per 5-unit increment was also related to a nearly 1.2-fold higher risk of RVSWI ≥ 12 g/m2/beat (OR 1.19, 95% CI 1.11-1.28, P < .001). These associations remained significant even after multivariable adjustment for confounding factors (all P < .05).

CONCLUSIONS

Increased mPAP, PVR, and RVSWI were associated with prolonged T90 in patients with OSA. Assessment of OSA with insights into hypoxemic duration may aid in early recognition of impaired pulmonary hemodynamics and RV dysfunction.

CITATION

Huang Z, Duan A, Hu M, et al. Implication of prolonged nocturnal hypoxemia and obstructive sleep apnea for pulmonary hemodynamics in patients being evaluated for pulmonary hypertension: a retrospective study. J Clin Sleep Med. 2023;19(2):213-223.

The effectiveness of sleep breathing impairment index in assessing obstructive sleep apnea severity

STUDY OBJECTIVES

Using the apnea-hypopnea index (AHI) and the sleep breathing impairment index (SBII) to assess the severity of obstructive sleep apnea (OSA) to study how effective SBII is in assessing the severity and cardiovascular disease (CVD) prognosis.

METHODS

This study comprised a total of 147 patients with diagnosed OSA. The AHI and SBII were calculated from the polysomnography. Patients were enrolled in the cluster analysis using 20 symptoms and the SBII. The prognostic indicator was determined as the moderate-to-high Framingham 10-year CVD risk.

RESULTS

Cluster analysis revealed 3 separate groups: cluster 1 (n = 45, 30.61%) had the lowest symptoms complaints yet the highest PSQI score; cluster 2 (n = 70, 47.62%) had considerably increased symptom complaints but the lowest Epworth Sleepiness Scale score, intermediate PSG indices, a higher low arousal threshold possibility, and a lower SBII quantile; cluster 3 (n = 32, 21.77%) had the largest percentage of smokers, a predominant symptom of restless sleep, severe PSG characteristics, a lower low arousal threshold likelihood, a greater SBII quantile and a higher Framingham CVD risk. There were no differences in severity indicated by AHI between groups. Higher SBII rather than AHI is associated with an increased 10-year CVD risk.

CONCLUSIONS

SBII provides higher sensitivity when evaluating OSA severity and better predictive capabilities for CVD outcomes. SBII may be a more effective substitute for AHI in the future.

CITATION

Dai L, Cao W, Luo J, Huang R, Xiao Y. The effectiveness of sleep breathing impairment index in assessing obstructive sleep apnea severity. J Clin Sleep Med. 2023;19(2):267-274.

Sleep Arousal-Related Ventricular Repolarization Lability Is Associated With Cardiovascular Mortality in Older Community-Dwelling Men

BACKGROUND

Sleep is fragmented by brief arousals, and excessive arousal burden has been linked to increased cardiovascular (CV) risk, but mechanisms are poorly understood.

RESEARCH QUESTION

Do arousals trigger cardiac ventricular repolarization lability that may predispose people to long-term cardiovascular mortality?

STUDY DESIGN AND METHODS

This study analyzed 407,541 arousals in the overnight polysomnograms of 2,558 older men in the Osteoporotic Fractures in Men sleep study. QT and RR intervals were measured beat-to-beat starting 15 s prior to arousal onset until 15 s past onset. Ventricular repolarization lability was quantified by using the QT variability index (QTVi).

RESULTS

During 10.1 ± 2.5 years of follow-up, 1,000 men died of any cause, including 348 CV deaths. During arousals, QT and RR variability increased on average by 5 and 55 ms, respectively, resulting in a paradoxical transient decrease in QTVi from 0.07 ± 1.68 to -1.00 ± 1.68. Multivariable Cox proportional hazards analysis adjusted for age, BMI, cardiovascular and respiratory risk factors, sleep-disordered breathing and arousal, diabetes, and Parkinson disease indicated that excessive QTVi during arousal was independently associated with all-cause and CV mortality (all-cause hazard ratio, 1.20 [95% CI, 1.04-1.38; P = .012]; CV hazard ratio, 1.29 [95% CI, 1.01 -1.65; P = .043]).

INTERPRETATION

Arousals affect ventricular repolarization. A disproportionate increase in QT variability during arousal is associated with an increased all-cause and CV mortality and may reflect ventricular repolarization maladaptation to the arousal stimulus. Whether arousal-related QTVi can be used for more tailored risk stratification warrants further study, including evaluating whether arousal suppression attenuates ventricular repolarization lability and reduces subsequent mortality.

CLINICAL TRIAL REGISTRATION

ClinicalTrials.gov; No.: NCT00070681; URL: www.

CLINICALTRIALS

gov.

Association of alternative polysomnographic features with patient outcomes in obstructive sleep apnea: a systematic review

STUDY OBJECTIVES

Polysomnograms (PSGs) collect a plethora of physiologic signals across the night. However, few of these PSG data are incorporated into standard reports, and hence, ultimately, under-utilized in clinical decision making. Recently, there has been substantial interest regarding novel alternative PSG metrics that may help to predict obstructive sleep apnea (OSA)-related outcomes better than standard PSG metrics such as the apnea-hypopnea index. We systematically review the recent literature for studies that examined the use of alternative PSG metrics in the context of OSA and their association with health outcomes.

METHODS

We systematically searched EMBASE, MEDLINE, and the Cochrane Database of Systematic Reviews for studies published between 2000 and 2022 for those that reported alternative metrics derived from PSG in adults and related them to OSA-related outcomes.

RESULTS

Of the 186 initial studies identified by the original search, data from 31 studies were ultimately included in the final analysis. Numerous metrics were identified that were significantly related to a broad range of outcomes. We categorized the outcomes into 2 main subgroups: (1) cardiovascular/metabolic outcomes and mortality and (2) cognitive function- and vigilance-related outcomes. Four general categories of alternative metrics were identified based on signals analyzed: autonomic/hemodynamic metrics, electroencephalographic metrics, oximetric metrics, and respiratory event-related metrics.

CONCLUSIONS

We have summarized the current landscape of literature for alternative PSG metrics relating to risk prediction in OSA. Although promising, further prospective observational studies are needed to verify findings from other cohorts, and to assess the clinical utility of these metrics.

CITATION

Hajipour M, Baumann B, Azarbarzin A, et al. Association of alternative polysomnographic features with patient outcomes in obstructive sleep apnea: a systematic review. J Clin Sleep Med. 2023;19(2):225-242.

Personalized multimodal management for severe obstructive sleep apnea in a patient intolerant of positive airway pressure with hypoglossal nerve stimulator and mandibular advancement device

Treatment of moderate to severe obstructive sleep apnea poses clinical challenges in persons with intolerance or inadequate response to traditional treatment modalities, including positive airway pressure and mandibular advancement devices. Hypoglossal nerve stimulation is a new treatment option, but few management guidelines exist when it is intolerable or ineffective. Combining several treatment modalities has been an effective strategy for improving symptoms, tolerance, and efficacy. We describe a patient intolerant to positive airway pressure therapy who had continued sleepiness, morning headaches, and snoring with a mandibular advancement device. He underwent hypoglossal nerve stimulation implantation but was intolerant of the voltages required to adequately control his obstructive sleep apnea. Multimodal management with hypoglossal nerve stimulation, mandibular advancement device, and positional therapy was successfully implemented to improve sleepiness, nocturnal symptoms, and the apnea-hypopnea index. This case highlights the personalization and adaptability of combination therapy to suit patient needs while effectively controlling obstructive sleep apnea.

CITATION

Lowery MM, Rundo JV, Walia HK, Shah V. Personalized multimodal management for severe obstructive sleep apnea in a patient intolerant of positive airway pressure with hypoglossal nerve stimulator and mandibular advancement device. J Clin Sleep Med. 2023;19(2):403-408.

Single-Night Diagnosis of Sleep Apnea Contributes to Inconsistent Cardiovascular Outcome Findings

BACKGROUND

Single-night disease misclassification of OSA due to night-to-night variability may contribute to inconsistent findings in OSA trials.

RESEARCH QUESTION

Does multinight quantification of OSA severity provide more precise estimates of associations with incident hypertension?

STUDY DESIGN AND METHODS

A total of 3,831 participants without hypertension at baseline were included in simulation analyses. Included participants had ≥ 28 days of nightly apnea-hypopnea index (AHI) recordings via an under-mattress sensor and ≥ 3 separate BP measurements over a 3-month baseline period followed by ≥ 3 separate BP measurements 6 to 9 months postbaseline. Incident hypertension was defined as a mean systolic BP ≥ 140 mm Hg or a mean diastolic BP ≥ 90 mm Hg. Simulated trials (1,000) were performed, using bootstrap methods to investigate the effect of variable numbers of nights (x = 1-56 per participant) to quantify AHI and the ability to detect associations between OSA and incident hypertension via logistic regression adjusted for age, sex, and BMI.

RESULTS

Participants were middle-aged (mean ± SD, 52 ± 12 y), mostly men (91%), and overweight (BMI, 28 ± 5 kg/m²). Single-night quantification of OSA failed to detect an association with hypertension risk in 42% of simulated trials (α = 0.05). Conversely, 100% of trials detected an association when AHI was quantified over ≥ 28 nights. Point estimates of hypertension risk were also 50% higher and uncertainty was 5 times lower during multinight vs single-night simulation trials.

INTERPRETATION

Multinight monitoring of OSA allows for better estimates of hypertension risk and potentially other adverse health outcomes associated with OSA. These findings have important implications for clinical care and OSA trial design.

Sleep Apnea and Incident Unprovoked Venous Thromboembolism: Data from the Pays de la Loire Sleep Cohort

BACKGROUND

 Previous studies have reported inconsistent findings regarding the association between obstructive sleep apnea (OSA) and incident venous thromboembolism (VTE). More specifically, the association between OSA and unprovoked VTE was barely evaluated. We aimed to evaluate whether apnea hypopnea index (AHI) and nocturnal hypoxemia markers were associated with unprovoked VTE incidence in patients investigated for OSA.

STUDY DESIGN AND METHODS

 Data from the Pays de la Loire Sleep Cohort were linked to the French health administrative data to identify incident unprovoked VTE in patients suspected for OSA and no previous VTE disease. Cox proportional hazards models were used to evaluate the association of unprovoked VTE incidence with AHI and nocturnal hypoxemia markers including the time spent under 90% of saturation (T90), oxygen desaturation index, and hypoxic burden (HB), a more specific marker of respiratory events related to hypoxia. The impact of continuous positive airway pressure (CPAP) was evaluated in the subgroup of patients who were proposed the treatment.

RESULTS

 After a median [interquartile range] follow-up of 6.3 [4.3-9.0] years, 104 of 7,355 patients developed unprovoked VTE, for an incidence rate of 10.8 per 1,000 patient-years. In a univariate analysis, T90 and HB predicted incident VTE. In the fully adjusted model, T90 was the only independent predictor (hazard ratio: 1.06; 95% confidence interval: [1.01-1.02]; p = 0.02). The CPAP treatment has no significant impact on VTE incidence.

CONCLUSION

 Patients with more severe nocturnal hypoxia are more likely to have incident unprovoked VTE.

Shorter respiratory event duration is related to prevalence of type 2 diabetes

BACKGROUND

Obstructive sleep apnea (OSA) is a heterogeneous sleep disorder often comorbid with metabolic diseases, and type 2 diabetes (T2DM) is one of them. Although apnea hypopnea index (AHI) is currently the diagnostic criteria for OSA severity, a controversial relationship between AHI and T2DM has been found. On the other hand, the duration of apnea-hypopnea events has been shown to be a useful metric for predicting mortality. This study aimed to test whether average respiratory event duration was associated with prevalence of T2DM.

METHODS

Patients referred to the sleep clinic were recruited in the study. Baseline clinical characteristics and polysomnography parameters including average respiratory event duration were collected. The association of average respiratory event duration with the prevalence of T2DM was evaluated by univariate and multivariate logistic regression analyses.

RESULTS

A total of 260 participants were enrolled, and 92 (35.4%) had T2DM. Univariate analysis revealed that age, body mass index (BMI), total sleep time, sleep efficiency, history of hypertension, and shorter average respiratory event duration were associated with T2DM. In multivariate analysis, only age and BMI remained significant. While average respiratory event duration was insignificant in multivariate analysis, subtype event analysis showed that shorter average apnea duration was both significant in univariate (OR, 0.95; 95% CI, 0.92-0.98) and multivariate analyses (OR, 0.95; 95% CI, 0.91-0.99). Neither average hypopnea duration nor AHI was associated with T2DM. Significant association (OR, 1.19; 95% CI, 1.12-1.25) was observed between shorter average apnea duration and lower respiratory arousal threshold after multivariate adjustment. However, causal mediation analysis revealed no mediating effect of arousal threshold on average apnea duration and T2DM.

CONCLUSION

The average apnea duration may be a useful metric in the diagnosis of OSA comorbidity. Shorter average apnea duration indicating poor sleep quality and augmented autonomic nervous system responses might be the potential pathological mechanisms leading to T2DM.

The norepinephrine reuptake inhibitor reboxetine alone reduces obstructive sleep apnea severity: a double-blind, placebo-controlled, randomized crossover trial

STUDY OBJECTIVES

Recent findings indicate that noradrenergic and muscarinic processes are crucial for pharyngeal muscle control during sleep. However, to date, reductions in obstructive sleep apnea (OSA) severity have only been detected when noradrenergic agents are combined with an antimuscarinic. Accordingly, this study aimed to determine if reboxetine alone and combined with oxybutynin reduces OSA severity. The pathophysiological mechanisms underpinning the effects of these agents were also investigated via endotyping analysis.

METHODS

Sixteen people (6 women) with OSA completed 3 polysomnograms (∼1-week washout) according to a double-blind, placebo-controlled, three-way crossover design across 2 sites. Single doses of 4 mg reboxetine, placebo, or 4 mg reboxetine + 5 mg oxybutynin were administered before sleep (order randomized).

RESULTS

Reboxetine reduced the apnea-hypopnea index (primary outcome) by 5.4 (95% confidence interval -10.4 to -0.3) events/h, P = .03 (-24 ± 27% in men; -0.7 ± 32% in women). Oxybutynin did not cause additional reductions in apnea-hypopnea index. Reboxetine alone reduced the 4% oxygen desaturation index by (mean ± standard deviation) 5.2 ± 7.2 events/h and reboxetine+oxybutynin by 5.1 ± 10.6 events/h vs placebo, P = .02. Nadir oxygen saturation also increased by 7 ± 11% with reboxetine and 5 ± 9% with reboxetine+oxybutynin vs placebo, P = .01. Mechanistically, reboxetine and reboxetine+oxybutynin improved pharyngeal collapsibility and respiratory control (loop gain). Larger reductions in apnea-hypopnea index with reboxetine in men were associated with higher baseline loop gain.

CONCLUSIONS

These findings show the first evidence that reboxetine alone reduces OSA severity. The data provide novel insight into the role of norepinephrine reuptake inhibitors on upper airway stability during sleep and are important to inform future pharmacotherapy development for OSA.

CLINICAL TRIAL REGISTRATION

Registry: Australian New Zealand Clinical Trials Registry; Name: Reboxetine and Combination Therapy with AD128 in Sleep Apnoea Trial: A Double-Blind, 3-Way Cross-Over Study; URL: https://www.anzctr.org.au/Trial/Registration/TrialReview.aspx?id=374614&isReview=true; Identifier: ACTRN12620000662965.

CITATION

Altree TJ, Aishah A, Loffler KA, Grunstein RR, Eckert DJ. The norepinephrine reuptake inhibitor reboxetine alone reduces obstructive sleep apnea severity: a double-blind, placebo-controlled, randomized crossover trial. J Clin Sleep Med. 2023;19(1):85-96.

Associations Between Amyloid Burden, Hypoxemia, Sleep Architecture, and Cognition in Obstructive Sleep Apnea

BACKGROUND

Obstructive sleep apnea (OSA) is associated with an increased risk of amyloid-β (Aβ) burden, the hallmark of Alzheimer's disease, and cognitive decline.

OBJECTIVE

To determine the differential impacts of hypoxemia and slow-wave sleep disruption on brain amyloid burden, and to explore the effects of hypoxemia, slow-wave sleep disruption, and amyloid burden on cognition in individuals with and without OSA.

METHODS

Thirty-four individuals with confirmed OSA (mean±SD age 57.5±4.1 years; 19 males) and 12 healthy controls (58.5±4.2 years; 6 males) underwent a clinical polysomnogram, a NAV4694 positron emission tomography (PET) scan for Aβ burden, assessment of APOEɛ status and cognitive assessments. Linear hierarchical regressions were conducted to determine the contributions of demographic and sleep variables on amyloid burden and cognition.

RESULTS

Aβ burden was associated with nocturnal hypoxemia, and impaired verbal episodic memory, autobiographical memory and set shifting. Hypoxemia was correlated with impaired autobiographical memory, and only set shifting performance remained significantly associated with Aβ burden when controlling for sleep variables.

CONCLUSIONS

Nocturnal hypoxemia was related to brain Aβ burden in this sample of OSA participants. Aβ burden and hypoxemia had differential impacts on cognition. This study reveals aspects of sleep disturbance in OSA that are most strongly associated with brain Aβ burden and poor cognition, which are markers of early Alzheimer's disease. These findings add weight to the possibility that hypoxemia may be causally related to the development of dementia; however, whether it may be a therapeutic target for dementia prevention in OSA is yet to be determined.

Cardiovascular outcomes in obstructive sleep apnoea and implications of clinical phenotyping on effect of CPAP treatment

BACKGROUND

There is a growing awareness of the heterogeneity of obstructive sleep apnoea (OSA). Clinical trials of CPAP treatment on cardiovascular protection have been mostly negative. We aimed to assess the association between polysomnographic parameters and incident major adverse cardiovascular events (MACEs), and to investigate if the CPAP effect could be better delineated among clinical subgroups.

METHODS

This sleep cohort study was conducted using a clinical database and territory-wide electronic health administration data in Hong Kong. Cox regressions were used to calculate HRs. Latent class analysis was used to cluster patients with OSA according to clinical and polysomnographic features.

RESULTS

Of 1860 eligible Chinese subjects who underwent polysomnography (2006-2013), 1544 (83%) had OSA. Over median follow-up of 8.3 years, 278 (14.9%) experienced MACEs. Apnoea-hypopnoea index (AHI) did not predict MACEs (HR: 0.95; 95% CI 0.76 to 1.17), whereas sleep time with oxygen saturation <90% (TST90) (HR: 1.41; 95% CI 1.10 to 1.81) was an independent predictor of MACEs, as were wake and nocturnal heart rate. In moderate-severe OSA (n=1108) who were indicated for CPAP treatment, regular CPAP was not associated with reduction of incident MACEs. Further cluster analysis identified a subgroup (n=333) who was younger, more obese, had more severe OSA (higher AHI and TST90) and more cardiovascular risks, in whom regular CPAP was associated with a lower risk of MACEs (HR:0.49, 95% CI 0.25 to 0.95).

CONCLUSIONS

OSA-related TST90 and mean heart rate, but not AHI, were robust predictors of MACEs. A clinical phenotype subgroup who demonstrated beneficial effect of CPAP treatment was identified.

Role of precision medicine in obstructive sleep apnoea

Obstructive sleep apnoea is a substantial clinical and public health problem because it contributes to harmful effects on quality of life, daytime symptoms, road traffic incidents, and cardiometabolic disease. Increasingly, obstructive sleep apnoea is recognised as a heterogeneous disease, and patients have varied susceptibility to long term complications and different responses to treatment. This narrative review summarises the current knowledge of precision medicine in obstructive sleep apnoea, particularly the role of symptom clusters, polysomnogram phenotypes, physiological endotypes, and circulating biomarkers in defining subtypes. In the near future, the prognostic accuracy of these measures in predicting long term complications in obstructive sleep apnoea will likely be improved, together with better matching of treatments to disease subtypes.

New Metrics from Polysomnography: Precision Medicine for OSA Interventions

Obstructive sleep apnea (OSA) is a highly preventable disease accompanied by multiple comorbid conditions. Despite the well-established cardiovascular and neurocognitive sequelae with OSA, the optimal metric for assessing the OSA severity and response to therapy remains controversial. Although overnight polysomnography (PSG) is the golden standard for OSA diagnosis, the abundant information is not fully exploited. With the development of deep learning and the era of big data, new metrics derived from PSG have been validated in some OSA consequences and personalized treatment. In this review, these metrics are introduced based on the pathophysiological mechanisms of OSA and new technologies. Emphasis is laid on the advantages and the prognostic value against apnea-hypopnea index. New classification criteria should be established based on these metrics and other clinical characters for precision medicine.

Hypoxic Burden in Obstructive Sleep Apnea: Present and Future

Conventional measures of obstructive sleep apnea (OSA) severity, such as the apnea-hypopnea index (AHI) and oxygen desaturation index (ODI) are commonly used to quantify OSA severity and guide therapeutical decision-making processes. However, it is widely recognized that both AHI and ODI have important limitations and novel physiologically-informed metrics are needed to better capture the severity of OSA and characterize its physiological consequences, particularly the severity of recurrent nocturnal hypoxemia, ensuing the respiratory events. According to recent studies, the sleep apnea-specific "hypoxic burden (HB)", defined as the sum of individual areas under the oxygen desaturation curve, has shown some promise in identifying high risk individuals with OSA. In addition to the frequency of respiratory events, HB capture the depth and duration of OSA-related hypoxemia that may prove to be important disease characterizing features, not captured by the conventional "frequency-based" metrics, such as AHI and ODI. In this "perspective" paper the methods to quantify the HB, its characteristics, associations with health outcomes, and its limitations will be discussed.

Should we treat with continuous positive airway pressure severe non-sleepy obstructive sleep apnea individuals without underlying cardiovascular disease?

The majority of the current international obstructive sleep apnea (OSA) guidelines base the recommendation to treat OSA with continuous positive airway pressure (CPAP) on the presence of symptoms (principally, albeit not exclusively on daytime hypersomnolence). In nonsleepy patients, even with severe OSA, controversies remain, as clear evidence supporting CPAP treatment of this subgroup of OSA patients is lacking. However, given the nonnegligible proportion of non-sleepy OSA patients, clinicians often face a serious dilemma since CPAP treatment in these patients may prove to be not cost-effective. Here, we propose a simple three-step-based algorithm that attempts to better phenotype non-sleepy OSA patients prior to reaching a CPAP treatment decision while also considering a series of clinically relevant elements in the process that may improve with CPAP therapy. Such algorithm focuses on the presence of several OSA symptoms that are susceptible to benefit from treatment and also relies on OSA phenotypes that need to be considered in an effort to achieve optimal cardiovascular prevention. Here, we attempt to establish a framework for clinicians who are evaluating severe nonsleepy OSA patients in their practices. However, the algorithm proposal needs to be extensively validated before being systematically implemented in clinical settings.

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.

Obstructive sleep apnea‐related intermittent hypoxaemia is associated with impaired vigilance

Obstructive sleep apnea (OSA)-related intermittent hypoxaemia is a potential risk factor for different OSA comorbidities, for example cardiovascular disease. However, conflicting results are found as to whether intermittent hypoxaemia is associated with impaired vigilance. Therefore, we aimed to investigate how desaturation characteristics differ between the non-impaired vigilance and impaired vigilance patient groups formed based on psychomotor vigilance task (PVT) performance and compared with traditional OSA severity parameters. The study population comprised 863 patients with suspected OSA who underwent a PVT test before polysomnography. The conventional OSA parameters, for example, the apnea-hypopnea index, oxygen desaturation index, and arousal index were computed. Furthermore, the median desaturation area, fall area, recovery area, and desaturation depth were computed with the pre-event baseline reference and with reference to the 100% oxygen saturation level. Patients were grouped into best- and worst-performing quartiles based on the number of lapses in PVT (Q1: PVT lapses <5 and Q4: PVT lapses >36). The association between parameters and impaired vigilance was evaluated by cumulative distribution functions (CDFs) and binomial logistic regression. Based on the CDFs, patients in Q4 had larger desaturation areas, recovery areas, and deeper desaturations when these were referenced to 100% saturation compared with Q1. The odds ratio (OR) of the median desaturation area (OR = 1.56), recovery area (OR = 1.71), and depth (OR = 1.65) were significantly elevated in Q4 in regression models. However, conventional OSA parameters were not significantly associated with impaired vigilance (ORs: 0.79-1.09). Considering desaturation parameters with a 100% SpO₂ reference in the diagnosis of OSA could provide additional information on the severity of OSA and related daytime vigilance impairment.

Nocturnal hypoxemia is related to morning negative affectivity in untreated patients with severe obstructive sleep apnea

The relationship between sleep apnea and morning affectivity remains unclear. We aimed to clarify how sleep disturbance in patients with obstructive sleep apnea (OSA) influences their affectivity. The enrolled participants underwent the Positive and Negative Affect Schedule on their beds immediately before and after overnight polysomnography. Thirty patients with OSA were divided into two groups according to the apnea-hypopnea index (AHI): mild to moderate OSA (5 ≤ AHI < 30/h) and severe OSA (AHI ≥ 30/h) groups. Additionally, 11 healthy participants (AHI < 5/h) were included as the control group. No independent association was found between affectivity and OSA severity markers in the whole population; however, the severe OSA group had a significantly higher cumulative percentage of sleep time at saturations < 90% (CT90) and worsened morning negative affectivity. Multiple regression analysis showed that CT90 was an independent factor for increasing negative affectivity in the severe OSA group (p = 0.0422). In patients with OSA, the receiver operating characteristic curve analysis showed that the best cutoff value for CT90 for predicting no decrease in negative affectivity after sleep was 1.0% (sensitivity = 0.56, specificity = 0.86); the corresponding area under the curve was 0.71. Worsening of negative affectivity in the morning was influenced by nocturnal hypoxemia in patients with severe OSA.

Personalized Medicine and Obstructive Sleep Apnea

Obstructive sleep apnea (OSA) is a common disease that is often under-diagnosed and under-treated in all ages. This is due to differences in morphology, diversity in clinical phenotypes, and differences in diagnosis and treatment of OSA in children and adults, even among individuals of the same age. Therefore, a personalized medicine approach to diagnosis and treatment of OSA is necessary for physicians in clinical practice. In children and adults without serious underlying medical conditions, polysomnography at sleep labs may be an inappropriate and inconvenient testing modality compared to home sleep apnea testing. In addition, the apnea-hypopnea index should not be considered as a single parameter for making treatment decisions. Thus, the treatment of OSA should be personalized and based on individual tolerance to sleep-quality-related parameters measured by the microarousal index, harmful effects of OSA on the cardiovascular system related to severe hypoxia, and patients' comorbidities. The current treatment options for OSA include lifestyle modification, continuous positive airway pressure (CPAP) therapy, oral appliance, surgery, and other alternative treatments. CPAP therapy has been recommended as a cornerstone treatment for moderate-to-severe OSA in adults. However, not all patients can afford or tolerate CPAP therapy. This narrative review seeks to describe the current concepts and relevant approaches towards personalized management of patients with OSA, according to pathophysiology, cluster analysis of clinical characteristics, adequate combined therapy, and the consideration of patients' expectations.

Desaturation event scoring criteria affect the perceived severity of nocturnal hypoxic load

OBJECTIVES/BACKGROUND

Interest in using blood oxygen desaturations in the diagnostics of sleep apnea has risen in recent years. However, no standardized criteria for desaturation scoring exist which complicates the drawing of solid conclusions from literature.

PATIENTS/METHODS

We investigated how different desaturation scoring criteria affect the severity of nocturnal hypoxic load and the prediction of impaired daytime vigilance in 845 patients. Desaturations were scored based on three features: 1) minimum oxygen saturation drop during the event (2-20%, 1% interval), 2) minimum duration of the event (2-20s, 1s interval), and 3) maximum plateau duration within the event (5-60s, 5s interval), resulting in 4332 different scoring criteria. The hypoxic load was described with oxygen desaturation index (ODI), desaturation severity (DesSev), and desaturation duration (DesDur) parameters. Association between hypoxic load and impaired vigilance was investigated with covariate-adjusted area under curve (AUC) analyses by dividing patients into normal (≤5 lapses) and impaired (≥36 lapses) vigilance groups based on psychomotor vigilance task performance.

RESULTS

The severity of hypoxic load varied greatly between different scoring criteria. For example, median ODI ranged between 0.4 and 12.9 events/h, DesSev 0.01-0.23 %-point, and DesDur 0.3-9.6 %-point when the minimum transient drop criterion of 3% was used and other two features were altered. Overall, the minimum transient drop criterion had the largest effect on parameter values. All models with differently determined parameters predicted impaired vigilance moderately (AUC = 0.722-0.734).

CONCLUSIONS

Desaturation scoring criteria greatly affected the severity of hypoxic load. However, the difference in the prediction of impaired vigilance between different criteria was rather small.

Effect of Pimavanserin on the Respiratory Arousal Threshold from Sleep: A Randomized Trial

Rationale: A low respiratory arousal threshold is a key endotype responsible for obstructive sleep apnea (OSA) pathogenesis. Pimavanserin is an antiserotoninergic capable of suppressing CO2-mediated arousals without affecting the respiratory motor response in animal models, and thus it holds potential for increasing the arousal threshold in OSA and subsequently reducing OSA severity. Objectives: We measured the effect of pimavanserin on arousal threshold (primary outcome), OSA severity, arousal index, and other OSA endotypes (secondary outcomes). Methods: A total of 18 OSA participants were studied in a randomized, double-blind, crossover study. Patients received a single dose of placebo or pimavanserin 34 mg 4 hours before in-lab polysomnography. Airflow was measured with an oronasal mask attached to a pneumotachograph, and ventilatory drive was recorded with an intraesophageal electromyography catheter. Results are presented as mean or median changes (Δ) and 95% confidence intervals (CIs). Results: Pimavanserin did not increase the arousal threshold, nor did it decrease OSA severity or arousal index. It, however, prolonged total sleep time (Δ[confidence interval (CI)], 39.5 [95%CI, -1.2 to 80.1] min). In an exploratory analysis, a subgroup of seven patients who had a 10% or more increase in arousal threshold on pimavanserin exhibited a decrease in AHI4 (hypopneas associated with 4% desaturation) (Δ[CI], 5.6 [95%CI, 3.6-11.1] events/h) and hypoxic burden (Δ[CI], 22.3 [95%CI, 6.6-32.3] %min/h). Conclusions: A single dose of pimavanserin did not have a significant effect on arousal threshold or OSA severity. However, in a post hoc analysis, a subset of patients who exhibited an increase in arousal threshold on pimavanserin showed a small decrease in OSA severity. Thus, if the arousal threshold could be increased with pimavanserin, perhaps with longer dosing to reach higher drug blood concentrations, then the desired effect on OSA severity might be achievable. Clinical trial registered with ClinicalTrials.gov (NCT04538755).

Associations between sleep apnea risk and cardiovascular disease indicators among Chinese and Korean Americans

STUDY OBJECTIVES

While sleep apnea has been associated with cardiovascular disease (CVD) risk factors in white individuals in the U.S., these associations in Chinese and Korean Americans are less well-understood, particularly how these associations vary by age, gender, Asian origin, obesity, chronic conditions, and daytime sleepiness.

METHODS

We used a sample of Chinese and Korean Americans ages 50-75 (n = 394) from the Baltimore-Washington DC Metropolitan Area to examine the associations of high risk (HR) sleep apnea with diagnoseable hypercholesterolemia and diabetes, as well as the following biomarkers: total cholesterol, low-density lipoprotein cholesterol (LDL-C), high-density lipoprotein cholesterol (HDL-C), total cholesterol/HDL-C ratio, triglycerides, and glucose (non-fasting). Poisson models included demographic factors, socioeconomic status, and body mass index (BMI). We tested for potential effect modifiers.

RESULTS

HR-sleep apnea was associated with higher LDL-C level (β = 14.56, p < 0.05) and higher total cholesterol/HDL ratio (β = 0.64, p < 0.01). Younger respondents had higher levels of triglycerides associated with HR-sleep apnea than older respondents. For men, HR-sleep apnea was associated with higher total cholesterol, total cholesterol/HDL-C ratio, and triglycerides. Obese and overweight respondents had positive associations between HR-sleep apnea and total cholesterol, total cholesterol/HDL ratio, and triglycerides, while underweight/normal weight individuals did not. The interactions between snoring and daytime sleepiness were associated with hypercholesterolemia and diabetes.

CONCLUSIONS

This study demonstrates associations between sleep apnea risk and dyslipidemia among Chinese and Korean Americans. Associations were particularly pronounced among younger, male, overweight/obese, and sicker individuals. Future research should examine how to improve sleep health in Asian American populations to improve CVD risk.

Positive Airway Pressure Adherence, Mortality, and Cardiovascular Events in Patients with Sleep Apnea

Rationale: Randomized controlled trials showed no effect of positive airway pressure (PAP) therapy for obstructive sleep apnea (OSA) on cardiovascular (CV) risk. However, patient selection and low PAP adherence preclude the generalization of their data to clinical samples. Objectives: To evaluate the association between hours of PAP use, mortality, and CV morbidity in real-life conditions. Methods: Data from the Pays de la Loire Cohort were linked to health administrative data to identify incident major adverse cardiovascular events (MACEs; a composite outcome of mortality, stroke, and cardiac diseases) in patients with OSA who were prescribed PAP. Cox proportional hazards analyses were conducted to evaluate the association between MACEs and quartiles of average daily PAP use over the study period. Measurements and Main Results: After a median follow-up of 6.6 years, 961 of 5,138 patients experienced MACEs. Considering nonadherent patients (0-4 h/night) as the reference group, adjusted hazard ratios (95% confidence intervals) for MACEs were 0.87 (0.73-1.04) for the 4-6 h/night group, 0.75 (0.62-0.92) for the 6-7 h/night group, and 0.78 (0.65-0.93) for the ⩾7 h/night group (P = 0.0130). Sensitivity analyses using causal inference approaches confirmed the association of PAP use with MACEs. The association was stronger in male patients (P value for interaction = 0.0004), patients without overt CV disease at diagnosis (P < 0.0001), and those belonging to the excessively sleepy symptom subtype (P = 0.060). Conclusions: These real-life clinical data demonstrate a dose-response relationship between PAP adherence and incident MACEs in OSA. Patient support programs may help improve PAP adherence and CV outcomes in patients with OSA.

Effectiveness of Tonsillectomy vs Modified Uvulopalatopharyngoplasty in Patients With Tonsillar Hypertrophy and Obstructive Sleep Apnea: The TEAMUP Randomized Clinical Trial

Importance

Modified uvulopalatopharyngoplasty (mUPPP) is a surgical treatment for selected adults with obstructive sleep apnea (OSA). Tonsillectomy (TE) alone is a less extensive alternative treatment.

Objective

To investigate whether mUPPP is more effective than TE alone in treating adult patients with tonsillar hypertrophy and moderate to severe OSA.

Design, Setting, and Participants

This blinded randomized clinical trial compared the effectiveness of mUPPP with TE alone before surgery and 6 months postsurgery in adults with tonsillar hypertrophy (sizes 2, 3, or 4 according to the Friedman staging) and moderate to severe OSA in a university hospital in Stockholm, Sweden. Participants underwent surgery from January 2016 to February 2021; the last postsurgery follow-up was completed in September 2021. Data analyses were performed from January to September 2022.

Interventions

mUPPP vs TE alone.

Main Outcomes and Measures

Between-group differences on the apnea-hypopnea index (AHI) and Epworth sleepiness scale (ESS).

Results

The study cohort comprised 93 patients (mean [SD] age, 41.6 [9.4] years; 80 [86%] men; race/ethnicity were not considered) with a mean (SD) body mass index of 29.0 (2.8), calculated as weight in kg divided by height in m2. Of these, 90 participants (97%) completed the protocol (mUPPP, n = 45; TE, n = 45). The mean (SD) AHI score (number of events per hour [events/h]) for the mUPPP group decreased by 43%, from 51.0 (22.6) to 28.0 (20.0) events/h; and for the TE group, 56%, from 56.9 (25.1) to 24.7 (22.6) events/h. The mean between-group difference in AHI score was 9.2 events/h (95% CI, 0.5 to 17.9), with a small effect size (Cohen d = 0.44) in favor of TE. For ESS scores, the between-group difference was also small, only 1.1 (95% CI, -1.3 to 3.4; Cohen d = 0.21). Neither difference was considered to be clinically relevant.

Conclusions and Relevance

This randomized clinical trial demonstrated that mUPPP was not more effective than TE alone in treating patients with tonsillar hypertrophy and moderate to severe OSA. However, there was a small difference in favor of TE. Because TE alone is less extensive, it could be considered as an alternative to mUPPP in this selected group of patients with OSA.

Trial Registration

ClinicalTrials.gov Identifier: NCT02523248.

Combination of atomoxetine with the novel antimuscarinic aroxybutynin improves mild to moderate OSA

STUDY OBJECTIVE

Obstructive sleep apnea is a common and serious sleep disorder for which treatment remains challenging due to lack of adherence to approved therapies. Previous pharmacological studies addressing sleep-related upper airway muscle hypotonia suggested that the combination of atomoxetine and oxybutynin is effective in treating obstructive sleep apnea. The current study is with aroxybutynin (AD109), a new enantiomerically pure form of oxybutynin with better safety profile compared to racemic oxybutynin.

METHODS

This was a randomized, double-blind, placebo-controlled, crossover study in patients with mild to moderate obstructive sleep apnea. Each received low-dose AD109 (37.5/2.5 mg), high-dose AD109 (75/2.5 mg), and placebo at bedtime across 3 overnight periods in a randomized order. Adverse events were collected by telephone contact with participants during each washout period. The primary endpoint was change in hypoxic burden and secondary endpoint was apnea-hypopnea index.

RESULTS

Patients treated with both the high and low doses of AD109 had a statistically significant and clinically meaningful difference from placebo in hypoxic burden. Median [interquartile range] hypoxic burden for participants on placebo was 13.9[4.5-21.9] (%min)/h vs 2.3[0.1-10.5] (%min)/h for patients on the high dose (P < .001) and to 7.3[2-12.5] (%min)/h on the low dose (P < .01). Apnea-hypopnea index went from a median of 13.2[8.0-19.1] events/h on placebo reduced to 5.5[2.2 to 9.6] events/h on the high dose (P < .001) and to 7.8[4-13.7] events/h on the low dose (P < .05). AD109 demonstrated a favorable safety profile.

CONCLUSIONS

This study provides additional support that a pharmacological intervention for obstructive sleep apnea, namely the combination of atomoxetine and aroxybutynin, offers promising results. Additional development of this compound and others is warranted.

CLINICAL TRIAL REGISTRATION

Registry: ClinicalTrials.gov; Name: AD109 Dose Finding in Mild to Moderate OSA; URL: https://clinicaltrials.gov/ct2/show/NCT04631107; Identifier: NCT04631107.

CITATION

Rosenberg R, Abaluck B, Thein S. Combination of atomoxetine with the novel antimuscarinic aroxybutynin improves mild to moderate OSA. J Clin Sleep Med. 2022;18(12):2837-2844.