The Effect of Continuous Positive Airway Pressure on Vascular Function and Cardiac Structure in Diabetes and Sleep Apnea. A Randomized Controlled Trial

Effects of Age and Sex on Systemic Inflammation and Cardiometabolic Function in Individuals with Type 2 Diabetes

Objective

Systemic inflammation, aging, and type 2 diabetes (T2DM) all contribute to the development of cardiovascular dysfunction and impaired aerobic exercise capacity but their interplay remains unclear. This study evaluates the impact of age, sex, and inflammation on coronary and peripheral vascular function and exercise capacity in elderly individuals with and without type 2 diabetes (T2DM).

Research Design and Methods

Elderly individuals (age ≥65 years) underwent biochemical and tissue inflammatory phenotyping, cardiopulmonary exercise testing (CPET), cardiovascular magnetic resonance (CMR) imaging, and vascular reactivity testing. Correlation and regression analyses determined the effects of systemic inflammation, older age, and sex on cardiovascular health, stratified by T2DM status.

Results

For the 133 recruited individuals (44% female; median age 71, IQR=7 years, 41% with T2DM) the presence of T2DM did not have an effect on most blood serum inflammatory markers and skin biopsies. Hyperemic myocardial blood flow (hMBF), flow-mediated, and flow-independent nitroglycerin induced brachial artery dilation were significantly impaired in males, but not females with T2DM. Peak VO2 was lower with T2DM (p=0.022), mostly because of the effect of T2DM in females. Females showed more adverse myocardial remodeling assessed by extracellular volume (p=0.008), independent of T2DM status.

Conclusions

Our findings suggest that the pathophysiological manifestations of T2DM on vascular function and aerobic exercise capacity are distinct in elderly males and females and this may reflect underlying differences in vascular and myocardial aging in the presence of T2DM.

The association between the effective apnea-hypopnea index and blood pressure reduction efficacy following CPAP/oxygen treatment

BACKGROUND

The effect of sleep apnea treatment on reducing cardiovascular disease risk remains inconclusive. This study aims to assess if the effective apnea hypopnea index (eAHI), a measure of residual sleep apnea burden post-treatment, is a factor in determining blood pressure (BP) response to continuous positive airway pressure therapy. The eAHI integrates time on therapy, residual apnea, and % of sleep time untreated.

METHODS

A secondary analysis of the Heart Biomarker Evaluation in Apnea Treatment (HeartBEAT) study, a randomized, controlled, parallel group assessment of continuous positive airway pressure (CPAP), oxygen and sleep hygiene. The Delta-AHI (▲AHI) was defined as the difference between baseline AHI and effective AHI at 12 weeks. Logistic and linear regression models estimated the predictors for nocturnal systolic BP change following sleep apnea therapy.

RESULTS

One hundred and sixty-nine subjects with a mean age of 62.82 ± 6.99 years were included in the final analysis. Fifty subjects had ▲AHI ≤8/hour of sleep and 119 subjects were higher. After adjustment, baseline mean nighttime systolic blood pressure (OR 1.036, 95% CI 1.015-1.058, p: 0.001) and ▲AHI ≥8/hour (OR 2.406, 95% CI 1.116-5.185, p:0.025) were independent predictors for mean nighttime systolic blood pressure change >3 mm Hg. The higher effective AHI was negatively related with BNP (β: -2.564, SE: 1.167, p: 0.029) and positively related with troponin change (β: 0.703, SE: 0.256, p: 0.007).

CONCLUSION

The ▲AHI was an independent predictor of the blood pressure response to sleep apnea treatment.

REGISTER NUMBER

NCT01086800.

The lived experience of positive airway pressure therapy in patients with obstructive sleep apnea across the lifespan: a qualitative study

STUDY OBJECTIVES

Although treatment of obstructive sleep apnea (OSA) with positive airway pressure (PAP) therapy is effective, adherence is often poor. Understanding the patient perspective is needed to inform adherence-promoting interventions. This qualitative study assessed the experiences, preferences, facilitators, and barriers surrounding PAP therapy for the management of OSA in patients from adolescence to older adulthood.

METHODS

Eligible participants ages 19 and older were identified from administrative health care claims; adolescent participants ages 12-18 and their parents/caregivers were identified via electronic health records of a tertiary sleep specialty clinic at a large children's hospital. Forty English-speaking patients and 10 parents of adolescents diagnosed with OSA and prescribed PAP therapy completed semistructured 60-minute telephone interviews conducted by a trained facilitator. Common themes and illustrative quotes were identified.

RESULTS

Themes around OSA diagnosis, initiating OSA treatment, learning about OSA/PAP, decision to start PAP, PAP benefits and challenges, and reasons for nonadherence were identified. Participants suggested design and delivery changes to improve PAP devices. Issues unique to adolescents and their parents were discussed.

CONCLUSIONS

The unique perspectives of patients regarding PAP therapy should be taken into consideration when developing interventions to increase PAP adherence and improve clinical care. Based on identified themes, opportunities for intervention may exist at all stages of care, from diagnosis to treatment initiation. Involving partners, parents, and other caregivers in PAP therapy may be beneficial for optimizing adherence.

CITATION

Simon SL, Stephenson JJ, Haynes K, et al. The lived experience of positive airway pressure therapy in patients with obstructive sleep apnea across the lifespan: a qualitative study. J Clin Sleep Med. 2024;20(3):407-416.

The causality between obstructive sleep apnea and ventricular structure and function: a bidirectional Mendelian randomization study

Background: Multiple observational studies have discovered a substantial link between obstructive sleep apnea (OSA) and ventricular dysfunction. However, conventional observational studies are vulnerable to causal reversal and confounding, making it challenging to infer the causes of effects and their direction. Methods: With the help of a bidirectional, two-sample Mendelian randomization (MR) study, we assessed the potential causality between OSA and left and right ventricular (LV, RV) structure and function. We conducted our analysis utilizing summary data from genome-wide association studies of OSA (16,761 cases and 201,194 controls) in the FinnGen Study, as well as LV (36,041 participants) and RV (29,506 participants) in the UK Biobank cardiovascular magnetic resonance research. The inverse variance weighted (IVW) was selected as the main strategy, with the MR-Egger and weighted median methods serving as supplements. Other methods were employed as sensitivity analysis tools to look at heterogeneity and pleiotropy, including MR-Egger intercept, Cochran Q statistic, MR-PRESSO, and leave-one-out analysis. Results: In the primary IVW analysis, genetically predicted OSA was strongly causative on LV end-diastolic volume (β = 0.114, 95% CI = 0.034-0.194, p = 0.006) and LV stroke volume (β = 0.111, 95% CI = 0.031-0.191, p = 0.007), and genetically predicted LV ejection fraction was linked to an increased risk of OSA (OR = 1.161, 95% CI = 1.029-1.309, p = 0.015). However, there was no connection found between OSA and any RV parameters. Conclusion: Our genetic analysis raises a potential causative link between OSA and ventricular structure and function, which may improve the knowledge of OSA as a risk factor for cardiovascular disease by demonstrating a direct impact on cardiac structure and function.

Effects of continuous positive airway pressure therapy on glucose metabolism in patients with obstructive sleep apnoea and type 2 diabetes: a systematic review and meta-analysis

Obstructive sleep apnoea is a highly prevalent chronic disorder and has been shown to be associated with disturbed glucose metabolism and type 2 diabetes. However, the evidence from individual clinical trials on the effect of continuous positive airway pressure (CPAP) treatment on glycaemic control in patients with co-existing obstructive sleep apnoea and type 2 diabetes remains controversial. A systematic review of randomised controlled trials assessing the effect of CPAP on glycaemic control in patients with obstructive sleep apnoea and type 2 diabetes was conducted using the databases MEDLINE, Embase, Cochrane and Scopus up to December 2022. Meta-analysis using a random-effect model was performed for outcomes that were reported in at least two randomised controlled trials. From 3031 records screened, 11 RCTs with a total of 964 patients were included for analysis. CPAP treatment led to a significant reduction in haemoglobin A1c (HbA1c) (mean difference -0.24%, 95% CI -0.43- -0.06%, p=0.001) compared to inactive control groups. Meta-regression showed a significant association between reduction in HbA1c and hours of nightly CPAP usage. CPAP therapy seems to significantly improve HbA1c and thus long-term glycaemic control in patients with type 2 diabetes and obstructive sleep apnoea. The amount of improvement is dependent on the hours of usage of CPAP and thus optimal adherence to CPAP should be a primary goal in these patients.

Defining the impact of continuous positive airway pressure therapy on diastolic function in adults with moderate-to-severe obstructive sleep apnea

Although studies have shown that continuous positive airway pressure (CPAP) therapy to treat obstructive sleep apnea improves left ventricular diastolic function, modifiers of improvement are unknown. We explored race and pre-treatment 24-h non-dipping blood pressure status as modifiers of improved diastolic function. Participants (N = 220) with obstructive sleep apnea (apnea-hypopnea index ≥15 events/h) and hypertension were recruited to a cohort study that examined effects of 3-month CPAP therapy on 24-h blood pressure. Those who completed echocardiogram at baseline and follow-up were included in this analysis. Diastolic function parameters (E, A, e', E/A, E/e') were assessed. Race was categorised to African American versus others. Participants were categorised as nocturnal dippers (night-time blood pressure decrease by ≥10%) versus non-dippers. We compared changes in parameters of diastolic function by race and nocturnal dipping status. A total of 92 participants were included. They were men (86%), African American (67.4%), and current smoker (29.5%). Mean apnea-hypopnea index was 32.9 events/h. Mean CPAP usage was 3.15 h/day. After 3 months of CPAP treatment, there were significant improvements in measures of diastolic function: a median (interquartile range [IQR]) increase in E velocity by 4.00 (-5.75 to 13.75) cm/s, an increase in e' by 2.00 (0-4.00) cm/s, and a decrease in the E/e' ratio by 1.74 (-4.27 to 0.00) at follow-up (p < 0.05). These changes did not differ by race or nocturnal dipping status. Improvements in diastolic function after CPAP therapy did not differ by race or nocturnal dipping status. Further studies are needed to understand predictors of CPAP effects on diastolic function.

Placebo response in objective and subjective measures of hypersomnia in randomized clinical trials on obstructive sleep apnea. A systematic review and meta-analysis

Sleepiness is one of the outcomes most used in randomized clinical trials (RCT) on the effect of treatments for obstructive sleep apnea (OSA). Furthermore, it is known that there is a placebo effect, especially in subjective measures. Therefore, given that sleepiness is a subjective measure, the objective of this systematic review with meta-analysis and three-level meta-regression was to assess the response to different placebos (pills and sham-CPAP) used in RCTs in OSA, both on subjective (Epworth Sleepiness Scale [ESS]) and objective (Multiple Sleep Latency Test [MSLT], Maintenance Wake Test [MWT], the Osler test and the Psychomotor Vigilance Task [PVT]). We observed a statistically significant placebo effect in both subjective and objective measures of hypersomnia, and in both sham-CPAP and pills. This placebo effect was greater, even clinically significant, in subjective measures (ESS: -2.84 points) and in those RCTs that used pills as a placebo. In the meta-regression, only a higher baseline value of the ESS and Osler test was related to the placebo effect.

Does Obstructive Sleep Apnoea Syndrome Influence the Development and Treatment of Diabetic Foot? A Brief Narrative Review

Both obstructive sleep apnoea syndrome (OSAS) and diabetes mellitus (DM) are common conditions that often coexist and share many similar risk factors. Diabetic foot is a common complication of DM, which may lead to lower-limb amputation. OSAS is considered a risk factor for type 2 DM (T2DM). There is also evidence that OSAS may be linked with the development, as well as the healing of diabetic foot. Multiple mechanisms triggered by sleep fragmentation and intermittent hypoxaemia in OSAS could contribute to the development of diabetic foot ulcers (DFUs). More interestingly, emerging evidence implies a favourable impact of continuous positive airway pressure (CPAP) treatment on DFU healing. Healing DFUs and minimising recurrence rates remains a challenge for health care professionals. In this context, management of OSAS might prove a useful therapeutic adjunct for DFUS. However, data is still limited and randomised controlled trials are needed to further explore this interesting potential.

Endothelial Function and Arterial Stiffness Should Be Measured to Comprehensively Assess Obstructive Sleep Apnea in Clinical Practice

Objective: An effective clinical tool to assess endothelial function and arterial stiffness in patients with obstructive sleep apnea (OSA) is lacking. This study evaluated the clinical significance of subclinical markers for OSA management in males without serious complications.

Patients/Methods: Males without serious complications were consecutively recruited. Clinical data, biomarker tests, reactive hyperemia index (RHI), and augmentation index at 75 beats/min (AIx75) measured by peripheral arterial tonometry were collected. An apnea hypopnea index (AHI) cutoff of ≥15 events/h divided the patients into two groups.

Results: Of the 75 subjects, 42 had an AHI ≥15 events/h. Patients with an AHI ≥15 events/h had higher high-sensitivity C-reactive protein, tumor necrosis factor-alpha (TNF-α), vascular endothelial growth factor, and AIx75 values than the control group but no statistical difference in RHI was observed. After controlling for confounders, TNF-α was negatively correlated with the average oxygen saturation (r = −0.258, P = 0.043). RHI was correlated with the rapid eye movement (REM) stage percentage (r = 0.306, P = 0.016) but not with AHI (P > 0.05). AIx75 was positively correlated with the arousal index (r = 0.289, P = 0.023) but not with AHI (r = 0.248, P = 0.052).

Conclusions: In males with OSA without severe complications, TNF-α and AIx75 are independently related to OSA. The role of RHI in OSA management requires further elucidation. These markers combined can comprehensively evaluate OSA patients to provide more evidence for the primary prevention of coronary heart disease and treatment response assessment.

Cardiovascular Disorders Triggered by Obstructive Sleep Apnea-A Focus on Endothelium and Blood Components

Obstructive sleep apnea (OSA) is known to be an independent cardiovascular risk factor. Among arousal from sleep, increased thoracic pressure and enhanced sympathetic activation, intermittent hypoxia is now considered as one of the most important pathophysiological mechanisms contributing to the development of endothelial dysfunction. Nevertheless, not much is known about blood components, which justifies the current review. This review focuses on molecular mechanisms triggered by sleep apnea. The recurrent periods of hypoxemia followed by reoxygenation promote reactive oxygen species (ROS) overproduction and increase inflammatory response. In this review paper we also intend to summarize the effect of treatment with continuous positive airway pressure (CPAP) on changes in the profile of the endothelial function and its subsequent potential clinical advantage in lowering cardiovascular risk in other comorbidities such as diabetes, atherosclerosis, hypertension, atrial fibrillation. Moreover, this paper is aimed at explaining how the presence of OSA may affect platelet function and exert effects on rheological activity of erythrocytes, which could also be the key to explaining an increased risk of stroke.

Benefits of continuous positive airway pressure on glycaemic control and insulin resistance in patients with type 2 diabetes and obstructive sleep apnoea: A meta-analysis

AIM

To conduct a meta-analysis to determine the effects of continuous positive airway pressure (CPAP) treatment on glycaemic control and insulin resistance in patients with type 2 diabetes and obstructive sleep apnoea (OSA).

METHODS

A systematic search was made of the MEDLINE, SCOPUS, ISI Web of Science, Cochrane databases, and clinicaltrials.gov, without language restrictions. Randomized controlled trials on treatment of type 2 diabetes and OSA with CPAP, compared with sham CPAP or no CPAP, were reviewed. Studies were pooled to obtain standardized mean differences (SMDs), with 95% confidence intervals (CIs).

RESULTS

Seven trials (enrolling 691 participants) met the inclusion criteria. CPAP showed significant effects on glycated haemoglobin (HbA1c; SMD -0.32, 95% CI -0.60 to -0.03; P = 0.029), fasting glucose (SMD -0.39, 95% CI -0.76 to -0.02; P = 0.040), homeostatic model assessment of insulin resistance (HOMA-IR; SMD -1.05, 95% CI -1.91 to -0.19; P = 0.016), systolic blood pressure (SMD -1.18, 95% CI -2.29 to -0.07 mm Hg; P = 0.037), and diastolic blood pressure (SMD -1.29, 95% CI -2.48 to -0.09; P = 0.035).

CONCLUSIONS

Continuous positive airway pressure treatment significantly improved glycaemic control and insulin resistance, as shown by the decreased HbA1c levels, fasting glucose levels and HOMA-IR values in patients with type 2 diabetes and OSA.

Effect of Obstructive Sleep Apnea and Positive Airway Pressure Therapy on Cardiac Remodeling as Assessed by Cardiac Biomarker and Magnetic Resonance Imaging in Nonobese and Obese Adults

It is unknown whether obesity modifies the effect of obstructive sleep apnea (OSA) and positive airway pressure (PAP) therapy on cardiac remodeling and NT-proBNP (N-terminal pro-B-type natriuretic peptide) levels. We compared NT-proBNP and cardiac magnetic resonance imaging in adults without OSA (n=56) and nonobese (n=73; body mass index <30 kg/m²) and obese (n=136; body mass index ≥30 kg/m²) adults with OSA. We also investigated these traits in nonobese (n=45) and obese (n=78) participants with OSA adherent to 4 months of PAP treatment. At baseline, left ventricular mass to end-diastolic volume ratio, a measure of left ventricular concentricity, was greater in both nonobese and obese participants with OSA compared with those without OSA. Participants with OSA and obesity exhibited reduced phasic right atrial function. No significant differences in baseline NT-proBNP were observed across groups. The effect of PAP treatment on NT-proBNP and left atrial volume index was significantly modified by obesity. In nonobese participants, PAP therapy was associated with a decrease in NT-proBNP (P<0.0001) without a change in left atrial volume index, whereas in obese participants, PAP was associated with an increase in left atrial volume index (P=0.006) without a change in NT-proBNP. OSA was associated with left ventricular concentric remodeling independent of obesity and right atrial dysfunction in participants who were obese. PAP treatment was associated with reduced NT-proBNP in nonobese participants with OSA, but left atrial enlargement in obese participants with OSA, suggesting that PAP-induced reduction in BNP release (which is known to occur during obstructive apnea episodes) may lead to volume retention in obese participants with OSA. Registration: URL: https://www.clinicaltrials.gov; Unique identifier: NCT01578031.