Pathophysiology Underlying Demographic and Obesity Determinants of Sleep Apnea Severity

Differences in Positive Airway Pressure Requirements in Obstructive Sleep Apnea Between Black and White Patients

OBJECTIVE

There are disparities between Black and White patients in the utilization of positive airway pressure (PAP) alternatives for obstructive sleep apnea (OSA). Given low utilization rates among Black patients, there is limited knowledge of PAP alternative outcomes in this group. Therapeutic PAP levels are clinically accessible measures that have been shown to predict PAP alternative outcomes. Herein, we examined differences in PAP requirements between Black and White patients in a large clinical sample.

STUDY DESIGN

Cross-sectional.

SETTING

Academic sleep center.

METHODS

We included OSA patients prescribed autoadjusting PAP between January 2018 and 2020 with baseline apnea-hypopnea index (AHI) ≥ 10. Mean and 90th percentile PAP levels were compared between White and Black patients who used PAP for ≥1 hour daily using linear regression controlling for age, sex, body mass index (BMI), AHI, oxygen saturation nadir, and mask type.

RESULTS

There were 157 Black and 234 White patients who were generally obese (BMI, 37.3 ± 8.7) with severe OSA (AHI, 36.9 ± 25.6). Black patients had a 0.68 cm higher (95% confidence interval [CI]: 0.36, 1.35) mean PAP level and 0.85 cm H2O higher (95% CI: 0.36, 1.35) 90th percentile PAP level than white patients. Although statistically significant, differences were small and not clinically meaningful.

CONCLUSION

Black and White OSA patients had clinically insignificant differences in PAP requirements, suggesting comparable upper airway collapsibility. Considering the predictive value of therapeutic PAP levels, our findings suggest Black and White patients may have comparable PAP alternative responses from a collapsibility standpoint. Future studies should explore reasons for low utilization of PAP alternatives among Black patients.

Obstructive sleep apnea and obesity: A review of epidemiology, pathophysiology and the effect of weight-loss treatments

Despite the commonly-accepted paradigm that patients with obstructive sleep apnea (OSA) also invariably have obesity, OSA prevalence extends beyond obesity. This necessitates a reevaluation of screening strategies, biomarkers of increased OSA risk, and heightened awareness among healthcare providers about the array of OSA treatments for diverse adult populations. While obesity contributes importantly to OSA pathogenesis, there is substantial evidence that non-anatomical factors also play a crucial role, especially in patients who do not have obesity. In recent years, notwithstanding the recognition of diverse contributors to OSA pathogenesis, research has frequently focused on weight reduction to address OSA. Insights from past experiences with bariatric surgery in OSA serve as a lens to anticipate potential outcomes of emerging anti-obesity pharmacotherapies. Pharmacological alternatives, particularly incretin agonists, exhibit promise in weight reduction and OSA improvement, but encounter obstacles such as potential side effects and high costs. With this comprehensive narrative review, we delve into the complex epidemiological and pathophysiological connections between OSA and obesity. Additionally, we emphasize the importance of a multifaceted approach to OSA treatment, recognizing that while weight management is crucial, there is a need for comprehensive strategies that go beyond traditional weight-centric perspectives.

Sex differences in sleep and sleep-disordered breathing

PURPOSE OF REVIEW

There is increasing evidence for relevant sex differences in pathophysiology, symptom presentation and outcomes in obstructive sleep apnoea (OSA). However, research on sex differences and sex-specific phenotypes in sleep-disordered breathing (SDB) is still in its infancy and data on sex differences in other SDB is still very scarce.

RECENT FINDINGS

While OSA is more common in men than in premenopausal women, the prevalence of OSA doubles postmenopausally and becomes comparable to that of men. Women have a lower collapsibility of the upper airway and a lower arousal threshold. In addition, the rapid eye movement (REM)-apnoea-hypopnoea index (AHI) is typically higher in women than in men, but the non-REM-AHI and thus the total AHI is often lower. Women are often symptomatic at lower AHI and present more frequently with symptoms of sleep fragmentation and poor sleep quality. Both certain forms of OSA (e.g. REM-OSA) and certain phenotypes (e.g. COMISA) are more common in women. Men have a higher risk of high loop gain central sleep apnoea.

SUMMARY

For a better understanding of sex-typical phenotypes with the aim of a more targeted treatment approach of SDB, adequately powered studies on sex differences in SDB should be conducted.

Tirzepatide for the treatment of obstructive sleep apnea: Rationale, design, and sample baseline characteristics of the SURMOUNT -OSA phase 3 trial

BACKGROUND

Weight reduction is a standard recommendation for obstructive sleep apnea (OSA) treatment in people with obesity or overweight; however, weight loss can be challenging to achieve and maintain without bariatric surgery. Currently, no approved anti-obesity medication has demonstrated effectiveness in OSA management. This study is evaluating the efficacy and safety of tirzepatide for treatment of moderate to severe OSA in people with obesity.

METHODS

SURMOUNT-OSA, a randomized, placebo -controlled, 52-week phase 3 trial, is investigating the efficacy and safety of tirzepatide for treatment of moderate to severe OSA (apnea hypopnea- index ≥15 events/h) in participants with obesity (body mass index ≥30 kg/m2) and an established OSA diagnosis. SURMOUNT-OSA is made of 2 intervention-specific appendices (ISAs): ISA-1 includes participants with no current OSA treatment, and ISA-2 includes participants using positive airway pressure therapy. Overall, 469 participants have been randomized 1:1 to receive tirzepatide or placebo across the master protocol (ISA-1, n = 234; ISA-2, n = 235). All participants are also receiving lifestyle intervention for weight reduction.

RESULTS

The primary endpoint for the individual ISAs is the difference in apnea hypopnea- index response, as measured by polysomnography, between tirzepatide and placebo arms at week 52. Secondary endpoints include sleep apnea-specific hypoxic burden, functional outcomes, and cardiometabolic biomarkers. The trial employs digital wearables, including home sleep testing to capture time to improvement and accelerometry for daily physical activity assessment, to evaluate exploratory outcomes.

CONCLUSION

SURMOUNT-OSA brings a novel design to investigate if tirzepatide provides clinically meaningful improvement in obesity-related OSA by targeting the underlying etiology.

TRIAL REGISTRATION

ClinicalTrials.gov, NCT05412004.

2024 Heart Disease and Stroke Statistics: A Report of US and Global Data From the American Heart Association

BACKGROUND

The American Heart Association (AHA), in conjunction with the National Institutes of Health, annually reports the most up-to-date statistics related to heart disease, stroke, and cardiovascular risk factors, including core health behaviors (smoking, physical activity, nutrition, sleep, and obesity) and health factors (cholesterol, blood pressure, glucose control, and metabolic syndrome) that contribute to cardiovascular health. The AHA Heart Disease and Stroke Statistical Update presents the latest data on a range of major clinical heart and circulatory disease conditions (including stroke, brain health, complications of pregnancy, kidney disease, congenital heart disease, rhythm disorders, sudden cardiac arrest, subclinical atherosclerosis, coronary heart disease, cardiomyopathy, heart failure, valvular disease, venous thromboembolism, and peripheral artery disease) and the associated outcomes (including quality of care, procedures, and economic costs).

METHODS

The AHA, through its Epidemiology and Prevention Statistics Committee, continuously monitors and evaluates sources of data on heart disease and stroke in the United States and globally to provide the most current information available in the annual Statistical Update with review of published literature through the year before writing. The 2024 AHA Statistical Update is the product of a full year's worth of effort in 2023 by dedicated volunteer clinicians and scientists, committed government professionals, and AHA staff members. The AHA strives to further understand and help heal health problems inflicted by structural racism, a public health crisis that can significantly damage physical and mental health and perpetuate disparities in access to health care, education, income, housing, and several other factors vital to healthy lives. This year's edition includes additional global data, as well as data on the monitoring and benefits of cardiovascular health in the population, with an enhanced focus on health equity across several key domains.

RESULTS

Each of the chapters in the Statistical Update focuses on a different topic related to heart disease and stroke statistics.

CONCLUSIONS

The Statistical Update represents a critical resource for the lay public, policymakers, media professionals, clinicians, health care administrators, researchers, health advocates, and others seeking the best available data on these factors and conditions.

Racial differences in upper airway collapsibility and loop gain in young adult males

STUDY OBJECTIVES

Previous studies reported that the apnea-hypopnea index was similar in young adult Black and White participants. However, whether this similarity reflects an analogous combination of apneas and hypopneas is unknown. Likewise, the physiological mechanisms underlying this similarity has not been explored.

METHODS

60 Black and 48 White males completed the study. After matching for age and body mass index, 41 participants remained in each group. All participants completed a sleep study. Subsequently, standard sleep indices along with loop gain and the arousal threshold were determined. In addition, airway collapsibility (24 of 60 and 14 of 48 participants) and the hypoxic ventilatory response during wakefulness (30 of 60 and 25 of 48 participants) was measured.

RESULTS

The apnea-hypopnea index was similar in Blacks and Whites (p = .140). However, the index was comprised of more apneas (p = .014) and fewer hypopneas (p = .025) in Black males. These modifications were coupled to a reduced loop gain (p = .0002) and a more collapsible airway (p = .030). These differences were independent of whether or not the groups were matched. For a given hypoxic response, loop gain was reduced in Black compared to White males (p = .023).

CONCLUSIONS

Despite a similar apnea-hypopnea index, more apneas and fewer hypopneas were evident in young adult Black compared to White males. The physiological mechanisms that contribute to these events were also different between groups. Addressing these differences may be important when considering novel therapeutic approaches to eliminate apnea in Black and White participants.

Annual review of selected scientific literature: A report of the Committee on Scientific Investigation of the American Academy of Restorative Dentistry

The Scientific Investigation Committee of the American Academy of Restorative Dentistry offers this review of the 2022 dental literature to briefly touch on several topics of interest to modern restorative dentistry. Each committee member brings discipline-specific expertise in their subject areas that include (in order of the appearance in this report): prosthodontics; periodontics, alveolar bone, and peri-implant tissues; dental materials and therapeutics; occlusion and temporomandibular disorders; sleep-related breathing disorders; oral medicine and oral and maxillofacial surgery; and dental caries and cariology. The authors focused their efforts on reporting information likely to influence the daily dental treatment decisions of the reader with an emphasis on innovations, new materials and processes, and future trends in dentistry. With the tremendous volume of literature published daily in dentistry and related disciplines, this review cannot be comprehensive. Instead, its purpose is to update interested readers and provide valuable resource material for those willing to subsequently pursue greater detail on their own. Our intent remains to assist colleagues in navigating the tremendous volume of newly minted information produced annually. Finally, we hope that readers find this work helpful in managing patients.

Obstructive sleep apnoea heterogeneity and cardiovascular disease

Obstructive sleep apnoea (OSA), characterized by recurrent periods of upper airway obstruction and intermittent hypoxaemia, is prevalent in patients with cardiovascular disease (CVD), and is therefore important to consider in the prevention and management of CVD. Observational studies indicate that OSA is a risk factor for incident hypertension, poorly controlled blood pressure, stroke, myocardial infarction, heart failure, cardiac arrhythmias, sudden cardiac death and all-cause death. However, clinical trials have not provided consistent evidence that treatment with continuous positive airway pressure (CPAP) improves cardiovascular outcomes. These overall null findings might be explained by limitations in trial design and low levels of adherence to CPAP. Studies have also been limited by the failure to consider OSA as a heterogeneous disorder that consists of multiple subtypes resulting from variable contributions from anatomical, physiological, inflammatory and obesity-related risk factors, and resulting in different physiological disturbances. Novel markers of sleep apnoea-associated hypoxic burden and cardiac autonomic response have emerged as predictors of OSA-related susceptibility to adverse health outcomes and treatment response. In this Review, we summarize our understanding of the shared risk factors and causal links between OSA and CVD and emerging knowledge on the heterogeneity of OSA. We discuss the varied mechanistic pathways that result in CVD that also vary across subgroups of OSA, as well as the potential role of new biomarkers for CVD risk stratification.