Continuous positive airway pressure improves sleepiness but not calculated vascular risk in patients with minimally symptomatic obstructive sleep apnoea: the MOSAIC randomised controlled trial

Long-term effects on clinical event, mental health, and related outcomes of CPAP for obstructive sleep apnea: a systematic review

STUDY OBJECTIVES

We performed a systematic review of long-term health outcomes of continuous positive airway pressure (CPAP) use in adults with obstructive sleep apnea.

METHODS

We updated prior systematic reviews with searches in multiple databases through January 3, 2023. We included randomized controlled trials (RCTs) and adjusted nonrandomized comparative studies that reported prespecified long-term (mostly > 1 year) health outcomes. We assessed risk of bias, conducted meta-analyses, and evaluated strength of evidence.

RESULTS

We found 38 eligible studies (16 trials, 22 observational). All conclusions were of low strength of evidence given study and data limitations. RCTs found no evidence of effect of CPAP on mortality (summary effect size [ES] 0.89; 95% confidence interval [CI] 0.66, 1.21); inclusion of adjusted nonrandomized comparative studies yields an association with reduced risk of death (ES 0.57; 95% CI 0.44, 0.73). RCTs found no evidence of effects of CPAP for cardiovascular death (ES 0.99; 95% CI 0.64, 1.53), stroke (ES 0.99; 95% CI 0.73, 1.35), myocardial infarction (ES 1.05; 95% CI 0.78, 1.41), incident atrial fibrillation (ES 0.89; 95% CI 0.48, 1.63), or composite cardiovascular outcomes (all statistically nonsignificant). RCTs found no evidence of effects for incident diabetes (ES 1.02; 95% CI 0.69, 1.51) or accidents (all nonsignificant) and no clinically significant effects on depressive symptoms, anxiety symptoms, or cognitive function.

CONCLUSIONS

Whether CPAP use for obstructive sleep apnea affects long-term health outcomes remains largely unanswered. RCTs and nonrandomized comparative studies are inconsistent regarding the effect of CPAP on mortality. Current studies are underpowered, with relatively short duration follow-up and methodological limitations.

CITATION

Balk EM, Adam GP, Cao W, Bhuma MR, D'Ambrosio C, Trikalinos TA. Long-term effects on clinical event, mental health, and related outcomes of CPAP for obstructive sleep apnea: a systematic review. J Clin Sleep Med. 2024;20(6):895-909.

Effects of Adaptive Servo-Ventilation on Quality of Life: The READ-ASV Registry

Rationale: Adaptive servo-ventilation (ASV) effectively treats sleep-disordered breathing, including central sleep apnea (CSA) and coexisting obstructive sleep apnea (OSA).Objectives: The prospective, multicenter European READ-ASV (Registry on the Treatment of Central and Complex Sleep-Disordered Breathing with Adaptive Servo-Ventilation) registry investigated the effects of first-time ASV therapy on disease-specific quality of life (QoL).Methods: The registry enrolled adults with CSA with or without OSA who had ASV therapy prescribed between September 2017 and March 2021. The primary endpoint was change in disease-specific QoL (Functional Outcomes of Sleep Questionnaire [FOSQ]) score between baseline and 12-month follow-up. Sleepiness determined using the Epworth Sleepiness Scale (ESS) score was a key secondary outcome. For subgroup analysis, participants were classified as symptomatic (FOSQ score < 17.9 and/or ESS score > 10) or asymptomatic (FOSQ score ⩾ 17.9 and/or ESS score ⩽ 10).Results: A total of 801 individuals (age, 67 ± 12 yr; 14% female; body mass index, 31 ± 5 kg/m2; apnea-hypopnea index, 48 ± 22/h) were enrolled; analyses include those with paired baseline and follow-up data. After 12 ± 3 months on ASV, median (interquartile range) FOSQ score had increased significantly from baseline (+0.8 [-0.2 to 2.2]; P < 0.001; n = 499). This was due to a significantly increased FOSQ score in symptomatic participants (+1.69 [0.38 to 3.05]), with little change in asymptomatic individuals (+0.11 [-0.39 to 0.54]). The median ESS score also improved significantly from baseline during ASV (-2.0 [-5.0 to 0.0]; P < 0.001).Conclusions: ASV treatment of CSA with or without coexisting OSA was associated with improvements in disease-specific QoL and daytime sleepiness, especially in individuals with sleep-disordered breathing symptoms before therapy initiation. These improvements in patient-reported outcomes support the use of ASV in this population.

Obstructive Sleep Apnea and Stroke: Determining the Mechanisms Behind their Association and Treatment Options

Sleep-disordered breathing (SDB) can be a sequela of stroke caused by vascular injury to vital respiratory centers, cerebral edema, and increased intracranial pressure of space-occupying lesions. Likewise, obstructive sleep apnea (OSA) contributes to increased stroke risk through local mechanisms such as impaired ischemic cerebrovascular response and systemic effects such as promoting atherosclerosis, hypercoagulability, cardiac arrhythmias, vascular-endothelial dysfunction, and metabolic syndrome. The impact of OSA on stroke outcomes has been established, yet it receives less attention in national guidelines on stroke management than hyperglycemia and blood pressure dysregulation. Furthermore, whether untreated OSA worsens stroke outcomes is not well-described in the literature. This scoping review provides an updated investigation of the correlation between OSA and stroke, including inter-relational pathophysiology. This review also highlights the importance of OSA treatment and its role in stroke outcomes. Knowledge of pathophysiology, the inter-relationship between these common disorders, and the impact of OSA therapy on outcomes affect the clinical management of patients with acute ischemic stroke. In addition, understanding the relationship between stroke outcomes and pre-existing OSA will allow clinicians to predict outcomes while treating acute stroke.

Large variability in definitions of sleep apnea indices used in clinical studies

STUDY OBJECTIVES

We explored the variability of sleep apnea indices and definitions of obstructive sleep apnea in clinical studies of continuous positive airway pressure.

METHODS

In a systematic review of the long-term clinical effects of continuous positive airway pressure, we noted variability across studies in how sleep apnea was defined. We, thus, sought to quantify the heterogeneity.

RESULTS

Across 57 comparative studies of long-term clinical outcomes of continuous positive airway pressure, only 40% fully and explicitly reported their definitions of apnea and hypopnea. Most studies defined apnea as 100% airflow cessation, but a minority used 90% or even down to 75% thresholds. Almost half of the studies defined hypopnea as ≥ 50% airflow cessation, but the majority used 30% or even 25% thresholds. Similarly, about half of the studies used a 4% desaturation threshold to define oxygen desaturation and about half used a 3% threshold, with 2 studies using both thresholds for different purposes. Randomized trials were no more consistent or better-reported than observational studies. Studies that cited published criteria generally reported definitions that were different from the cited criteria.

CONCLUSIONS

The criteria used to define sleep apnea indices (apnea, hypopnea, and oxygen desaturation) were highly variable, even among studies stating that definitions were based on the same standard criteria. It was often difficult to discern the actual criteria used. The great variability across studies and lack of transparency about their sleep study methods hampers the interpretability and utility of the studies and calls into question whether studies are generalizable from one setting to another.

CITATION

Balk EM, Adam GP, D'Ambrosio CM. Large variability in definitions of sleep apnea indices used in clinical studies. J Clin Sleep Med. 2024;20(3):461-468.

Effects of CPAP and Mandibular Advancement Devices on depressive symptoms in patients with obstructive sleep apnea: a meta-analysis of randomized controlled trials

PURPOSE

Studies show that patients with obstructive sleep apnea (OSA) are more likely than the general population to have psychological disorders such as depression. However, it is less clear how OSA treatment affects this association. This meta-analysis aimed to assess whether or not continuous positive airway pressure (CPAP) and mandibular advancement devices (MADs) reduce depression symptoms in patients with OSA.

METHODS

We searched Pubmed, Embase, Web of Science, and Cochrane Library from creating the databases until November 2022. Our analysis included RCTs that examined CPAP and MAD treatment effectiveness for depression in patients with OSA.

RESULTS

We identified 17 CPAP studies comprising 1,931 patients for inclusion in the meta-analysis. The results of the meta-analysis using a fixed effects model found that CPAP improved depressed mood in patients with OSA relative to controls (SMD = 0.27;95% CI:0.18,0.36), with small heterogeneity among trials (I2 = 8.1% < 50%, P = 0.359). We performed subgroup analyses on three factors: the length of trial follow-up, patient adherence data, and depression assessment scales. The meta-analysis also identified six MAD studies involving 315 patients. According to this analysis, there was no heterogeneity between studies (I2 = 0%, P = 0.748). MADs did not significantly improve depression symptoms compared to controls, indicating a combined effect of SMD = 0.07 (95% CI: - 0.15,0.29), P > 0.05.

CONCLUSION

The present findings confirm that CPAP may improve depressive symptoms in patients with OSA. However, the review results suggest that MADs have no significant effect on depressive symptoms in patients with OSA, a finding that is different from the results of previous meta-analyses.

Efficacy of vibrotactile positional therapy devices on patients with positional obstructive sleep apnoea: a systematic review and meta-analysis

INTRODUCTION

Vibrotactile positional therapy (PT) devices are a new treatment modality for positional obstructive sleep apnoea (POSA). This review aimed to determine the effect of vibrotactile PT on the Apnoea Hypopnoea Index (AHI) and the percentage of time spent in the supine position (%Tsupine) in patients with POSA, compared with baseline. Secondary aims were to investigate the effect on daytime sleepiness, quality of life and sleep quality.

METHODS

A systematic review and meta-analysis was performed of randomised controlled trials (RCTs) and cohort studies that investigated the effect of vibrotactile PT in POSA patients. Searches were performed via MEDLINE, CENTRAL and Embase up to 29 October 2022.

RESULTS

1119 studies were identified, 18 studies met the inclusion criteria (10 RCTs, 8 cohort studies). The use of vibrotactile PT significantly reduced the AHI at follow-up compared with baseline (mean difference (95% CI) -9.19 events/hour (-11.68 to -6.70); p<0.00001). The mean %Tsupine was also significantly reduced (mean difference (95% CI) -32.79% (-38.75% to -26.83%); p<0.00001). The percentage changes in the AHI and %Tsupine were 43% and 70%, respectively. Secondary outcomes were daytime sleepiness, quality of life and sleep indices. These showed minimal change, although follow-up was short.

CONCLUSION

Vibrotactile PT devices are effective in treating POSA; reducing both AHI and %Tsupine. The effect on sleep quality, daytime sleepiness and disease-specific quality of life was minimal. However, there were limited data and follow-up was often brief, meaning that further research is needed to determine the effect of vibrotactile PT on patient-centred outcomes.

PROSPERO REGISTRATION NUMBER

CRD42020188617.

Efficacy and safety of liraglutide in patients with type 2 diabetes mellitus and severe obstructive sleep apnea

OBJECTIVES

To observe the efficacy and side effects of liraglutide in the treatment of type 2 diabetes mellitus (T2DM) patients with severe obstructive sleep apnea (OSA).

METHODS

The study conducted in an outpatient setting was a two-center, prospective randomized controlled study. T2DM patients with severe OSA were randomized to the control group (continuous positive airway pressure [CPAP] and drug treatment without liraglutide) or the liraglutide group (CPAP and drug treatment including liraglutide). Demographic and clinical characteristics, sleep-disordered breathing indices, cardiac function indices, and side effects were evaluated and compared between the two groups before and after 3 months.

RESULTS

Of 90 patients, 45 were randomized to the intervention arm (with liraglutide) and 45 to the control arm (without liraglutide). One patient in the liraglutide group dropped out of the study on day 8 after enrollment due to obvious gastrointestinal symptoms. No significant differences were found between the two groups in baseline demographics, clinical characteristics, cardiac function indicators, or sleep disorder respiratory indices (P > 0.05). After 3 months, the body mass index (BMI), apnea hypopnea index (AHI), and mean systolic blood pressure in the liraglutide treatment group were significantly lower than those in the control group (P < 0.05). The minimum oxygen saturation was significantly higher in the liraglutide group compared with that in the control group after 3 months of follow-up (P < 0.05). No difference was found between the two groups in the summary of side effects (P > 0.05).

CONCLUSIONS

Liraglutide combined with CPAP can effectively reduce BMI, lower mean systolic blood pressure, and improve AHI scores and hypoxia in T2DM patients with severe OSA. Liraglutide did not increase side effects.

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.

Endotyping, phenotyping and personalised therapy in obstructive sleep apnoea: are we there yet?

Obstructive sleep apnoea (OSA) was traditionally thought to be mainly caused by obesity and upper airway crowding, and hence OSA management was not personalised according to particular characteristics, with most symptomatic patients receiving continuous positive airway pressure therapy. Recent advances in our understanding have identified additional potential and distinct causes of OSA (endotypes), and subgroups of patients (phenotypes) with increased risk of cardiovascular complications. In this review, we discuss the evidence to date as to whether there are distinct clinically useful endotypes and phenotypes of OSA, and the challenges to the field in moving towards delivering personalised therapy in OSA.

Effect of positive airway pressure compliance on laryngopharyngeal reflux in obstructive sleep apnea patients

OBJECTIVES

To determine the effect of continuous positive airway pressure (CPAP) compliance on symptoms and signs of laryngopharyngeal reflux (LPR) in patients with obstructive sleep apnea (OSA).

RESULTS

Thirty patients were included. The participants were divided into good compliance (n = 21) and poor compliance (n = 9) groups. After 6-month CPAP treatment, the reflux symptom index score significantly decreased in both the good compliance group (20 (17,24) vs. 14 (10,18), p < 0.001) and the poor compliance group (21 (18,25) vs. 10 (5,16), p < 0.05). Reflux finding score was significantly reduced in both the good compliance group (8 (6,9) vs. 4 (3,5), p < 0.001) and the poor compliance group (6 (4,8) vs. 3 (2,4), p < 0.05). However, there were no statistically significant differences between the groups. CPAP treatment reduces the symptoms and signs of LPR. However, CPAP compliance does not correlate with improvement in LPR in patients with OSA.

Obstructive Sleep Apnea and Its Management: A Narrative Review

Obstructive sleep apnea (OSA) is a disorder in which there is repeated collapse of the upper airway when the person is in sleep, which causes oxygen desaturation and interrupted sleep. While asleep, airway blockages and collapse are accompanied by awakenings with or without oxygen desaturation. OSA is a prevalent disorder, especially in people with known risk factors and other illnesses. Pathogenesis is variable, and the risk factors include low chest volume, erratic respiratory regulation, and muscular dysfunction in the upper airway dilators. The high-risk factors include overweight, male sex, aging, adenotonsillar hypertrophy, interruption of the menstrual cycle, preservation of liquids, and smoking. The signs are snoring, drowsiness, and apneas. A sleep history, assessment of symptoms, and physical examination are all part of the screening process for OSA, and the data can help determine which people need to be tested for the condition. The results of the polysomnogram or at-home sleep apnea test assist in determining the presence and severity of OSA. Still, it is seen many times that the accuracy of home sleep apnea tests is significantly less, so one should take an expert opinion for the same. OSA results in systemic hypertension, drowsiness, and driving accidents. It is additionally related to diabetes mellitus, congestive heart failure (CHF), cerebral infarction, and myocardial infarction, but the exact mechanism is not known. The preferred treatment is continuous positive airway pressure with 60-70% adherence. Other management options include reducing weight, therapy of oral appliances, and correcting any anatomical obstruction (narrow pharyngeal airway, adenoid hypertrophy, and mass in the pharynx). OSA indirectly causes headaches just after awakening and daytime sleepiness. However, there are no age boundaries in OSA as it can occur in any age group. Still, more prevalence is seen in individuals of more than 60 years of age.

Effect of Continuous Positive Airway Pressure on Glucose and Lipid Profiles in Patients With Obstructive Sleep Apnoea: A Systematic Review and Meta-Analysis of Randomized Controlled Trials

BACKGROUND AND AIM

Continuous Positive Airway Pressure (CPAP) is the most effective therapy for symptomatic obstructive sleep apnoea (OSA). However, uncertainty remains about the effectiveness of CPAP in improving OSA-related metabolic dysregulation. This meta-analysis of randomized controlled trials (RCTs) aimed to investigate whether CPAP, compared to other control treatments, could improve glucose or lipid metabolism in OSA patients.

METHODS

Relevant articles were searched in three different databases (MEDLINE, EMBASE and Web of Science) from inception to 6th Feb 2022 through specific search terms and selection criteria.

RESULTS

From a total of 5553 articles, 31 RCTs were included. CPAP modestly improved insulin sensitivity as determined by mean fasting plasma insulin and Homeostasis Model Assessment of Insulin Resistance reduction of 1.33mU/L and 0.287, respectively. In subgroup analyses pre-diabetic/type 2 diabetic patients as well as those with sleepy OSA showed a greater response to CPAP. Regarding lipid metabolism, CPAP was associated with a mean total cholesterol reduction of 0.064mmol/L. In subgroup analyses, the benefit was higher in patients that showed more severe OSA and oxygen desaturations at the baseline sleep study as well as in younger and obese subjects. Neither glycated haemoglobin nor triglycerides, HDL- and LDL-cholesterol were reduced by CPAP.

CONCLUSION

CPAP treatment may improve insulin sensitivity and total cholesterol levels in OSA patients but with low effect size. Our results suggest that CPAP does not substantially improve metabolic derangements in an unselected OSA population, but the effect may be higher in specific subgroups of OSA patients.

Right ventricular responses to CPAP therapy in obstructive sleep apnea: CMR analysis of the MOSAIC randomized trial

Effects of continuous positive airway pressure (CPAP) on right ventricular (RV) function in patients with untreated mild-to-moderate obstructive sleep apnea (OSA) are unclear. In this exploratory analysis of cardiac magnetic resonance (CMR)-derived indices of RV function in patients with minimally symptomatic OSA from the MOSAIC randomized control trial we found no effect of CPAP on RV CMR parameters. In those with lower RV ejection fraction and higher RV end-diastolic volume (EDV) at baseline, CPAP treatment appeared to improve RV function with a significant reduction in both RV EDV and RV end-systolic volume although between-group effects were not observed. These data suggest potential merit in a larger randomized study of CPAP in patients with mild-to-moderate OSA and a greater breadth of RV dysfunction.

Screening for Obstructive Sleep Apnea in Adults: Updated Evidence Report and Systematic Review for the US Preventive Services Task Force

IMPORTANCE

Obstructive sleep apnea (OSA) is associated with adverse health outcomes.

OBJECTIVE

To review the evidence on screening for OSA in asymptomatic adults or those with unrecognized OSA symptoms to inform the US Preventive Services Task Force.

DATA SOURCES

PubMed/MEDLINE, Cochrane Library, Embase, and trial registries through August 23, 2021; surveillance through September 23, 2022.

STUDY SELECTION

English-language studies of screening test accuracy, randomized clinical trials (RCTs) of screening or treatment of OSA reporting health outcomes or harms, and systematic reviews of treatment reporting changes in blood pressure and apnea-hypopnea index (AHI) scores.

DATA EXTRACTION AND SYNTHESIS

Dual review of abstracts, full-text articles, and study quality. Meta-analysis of intervention trials.

MAIN OUTCOMES AND MEASURES

Test accuracy, excessive daytime sleepiness, sleep-related and general health-related quality of life (QOL), and harms.

RESULTS

Eighty-six studies were included (N = 11 051). No study directly compared screening with no screening. Screening accuracy of the Multivariable Apnea Prediction score followed by unattended home sleep testing for detecting severe OSA syndrome (AHI ≥30 and Epworth Sleepiness Scale [ESS] score &gt;10) measured as the area under the curve in 2 studies (n = 702) was 0.80 (95% CI, 0.78 to 0.82) and 0.83 (95% CI, 0.77 to 0.90). Five studies assessing the accuracy of other screening tools were heterogeneous and results were inconsistent. Compared with inactive control, positive airway pressure was associated with a significant improvement in ESS score from baseline (pooled mean difference, -2.33 [95% CI, -2.75 to -1.90]; 47 trials; n = 7024), sleep-related QOL (standardized mean difference, 0.30 [95% CI, 0.19 to 0.42]; 17 trials; n = 3083), and general health-related QOL measured by the 36-Item Short Form Health Survey (SF-36) mental health component summary score change (pooled mean difference, 2.20 [95% CI, 0.95 to 3.44]; 15 trials; n = 2345) and SF-36 physical health component summary score change (pooled mean difference, 1.53 [95% CI, 0.29 to 2.77]; 13 trials; n = 2031). Use of mandibular advancement devices was also associated with a significantly larger ESS score change compared with controls (pooled mean difference, -1.67 [95% CI, 2.09 to -1.25]; 10 trials; n = 1540). Reporting of other health outcomes was sparse; no included trial found significant benefit associated with treatment on mortality, cardiovascular events, or motor vehicle crashes. In 3 systematic reviews, positive airway pressure was significantly associated with reduced blood pressure; however, the difference was relatively small (2-3 mm Hg).

CONCLUSIONS AND RELEVANCE

The accuracy and clinical utility of OSA screening tools that could be used in primary care settings were uncertain. Positive airway pressure and mandibular advancement devices reduced ESS score. Trials of positive airway pressure found modest improvement in sleep-related and general health-related QOL but have not established whether treatment reduces mortality or improves most other health outcomes.

Influence of continuous positive airway pressure on lipid profiles of obstructive sleep apnea: A systematic review and meta-analysis

BACKGROUND

To investigate the influence of continuous positive airway pressure (CPAP) on lipid profiles of the patients with obstructive sleep apnea (OSA) in this meta-analysis.

METHODS

Relevant studies reporting the correlation between CPAP and lipid profiles of OSA patients were searched in Pubmed, Cochrane Library and Embase before January 1, 2021. Data of eligible studies were extracted and analyzed using the fixed-effect or random-effect model. Standard mean difference (SMD) and 95% confidence interval (95% CI) were calculated to assess such influence. Subgroup analysis based on CPAP duration was further performed. STATA 12.0 was used in this meta-analysis.

RESULTS

A total of 12 independent randomized controlled studies involved 1129 OSA patients were recruited in this meta-analysis. The analyzed lipid profiles included total cholesterol (TC), triglyceride (TG), low density lipoprotein (LDL) and high density lipoprotein (HDL). CPAP was not correlated to TC (SMD = -0.07, 95% CI = -0.33 to 0.19), TG (SMD = -0.01, 95% CI = -0.19 to 0.17), LDL (SMD = -0.01, 95% CI = -0.23 to 0.21) and HDL (SMD = 0.10, 95% CI = -0.03 to 0.22) in OSA patients. Moreover, CPAP duration (=12 weeks; >12 weeks; <12 weeks) also did not influence lipid profiles of OSA patients as well.

CONCLUSIONS

Regardless of the treatment in CPAP duration, it doses does not influence lipid profiles of OSA patients, including TC, TG, LDL and HDL. The results are inconsistent with previous findings, which should be further validated in the multi-center, long-term randomized controlled trials.

Sex differences in Epworth Sleepiness Scale normalization with continuous positive airway pressure

STUDY OBJECTIVES

Continuous positive airway pressure (CPAP) improves sleepiness in patients with obstructive sleep apnea, but some patients remain sleepy. The objective of this study was to identify determinants that are associated with improvements in self-reported sleepiness in patients with obstructive sleep apnea on CPAP therapy.

METHODS

A retrospective cohort study was performed in a clinic-based population to determine which variables contributed to the improvement in the Epworth Sleepiness Scale (ESS) in patients on CPAP therapy for OSA, stratified by baseline ESS score (< 11 or ≥ 11). Variables associated with ESS scores normalizing with CPAP were also assessed.

RESULTS

Patients with a baseline high ESS score showed greater improvements in the ESS with CPAP. When looking at interactions between baseline ESS classification and changes in ESS, we found that a higher apnea-hypopnea index was only associated with improvement in the ESS among patients with a high baseline ESS. Other assessed factors or covariates were not significantly different. When looking at ESS normalization, we found that female sex and lower body mass index were associated with a lower likelihood of ESS normalization. The difference in the rate of ESS normalization between females and males was higher with more days on CPAP.

CONCLUSIONS

Of all the assessed factors and covariates, only the apnea-hypopnea index was associated with the change in the ESS differently in patients with a high or normal baseline ESS score. ESS normalization rates were lower in females than in males, and this disparity was amplified by more days on CPAP.

CITATION

Scharf MT, Zhang P, Walker NA, et al. Sex differences in Epworth Sleepiness Scale normalization with continuous positive airway pressure. J Clin Sleep Med. 2022;18(9):2273-2279.

Effect of an Interdisciplinary Weight Loss and Lifestyle Intervention on Obstructive Sleep Apnea Severity: The INTERAPNEA Randomized Clinical Trial

IMPORTANCE

Obesity is the leading cause of obstructive sleep apnea (OSA); however, the effects of weight loss and lifestyle interventions on OSA and comorbidities remain uncertain.

OBJECTIVE

To evaluate the effect of an interdisciplinary weight loss and lifestyle intervention on OSA and comorbidities among adults with moderate to severe OSA and overweight or obesity.

DESIGN, SETTING, AND PARTICIPANTS

The Interdisciplinary Weight Loss and Lifestyle Intervention for OSA (INTERAPNEA) study was a parallel-group open-label randomized clinical trial conducted at a hospital-based referral center in Granada, Spain, from April 1, 2019, to October 23, 2020. The study enrolled 89 Spanish men aged 18 to 65 years with moderate to severe OSA and a body mass index (calculated as weight in kilograms divided by height in meters squared) of 25 or greater who were receiving continuous positive airway pressure (CPAP) therapy. The sole inclusion of men was based on the higher incidence and prevalence of OSA in this population, the differences in OSA phenotypes between men and women, and the known effectiveness of weight loss interventions among men vs women.

INTERVENTIONS

Participants were randomized to receive usual care (CPAP therapy) or an 8-week weight loss and lifestyle intervention involving nutritional behavior change, aerobic exercise, sleep hygiene, and alcohol and tobacco cessation combined with usual care.

MAIN OUTCOMES AND MEASURES

The primary end point was the change in the apnea-hypopnea index (AHI) from baseline to the intervention end point (8 weeks) and 6 months after intervention. Secondary end points comprised changes in other OSA sleep-related outcomes, body weight and composition, cardiometabolic risk, and health-related quality of life.

RESULTS

Among 89 men (mean [SD] age, 54.1 [8.0] years; all of Spanish ethnicity; mean [SD] AHI, 41.3 [22.2] events/h), 49 were randomized to the control group and 40 were randomized to the intervention group. The intervention group had a greater decrease in AHI (51% reduction; change, -21.2 events/h; 95% CI, -25.4 to -16.9 events/h) than the control group (change, 2.5 events/h; 95% CI, -2.0 to 6.9 events/h) at the intervention end point, with a mean between-group difference of -23.6 events/h (95% CI, -28.7 to -18.5 events/h). At 6 months after intervention, the reduction in AHI was 57% in the intervention group, with a mean between-group difference of -23.8 events/h (95% CI, -28.3 to -19.3 events/h). In the intervention group, 18 of 40 participants (45.0%) no longer required CPAP therapy at the intervention end point, and 6 of 40 participants (15.0%) attained complete OSA remission. At 6 months after intervention, 21 of 34 participants (61.8%) no longer required CPAP therapy, and complete remission of OSA was attained by 10 of 34 participants (29.4%). In the intervention vs control group, greater improvements in body weight (change, -7.1 kg [95% CI, -8.6 to -5.5 kg] vs -0.3 kg [95% CI, -1.9 to 1.4 kg]) and composition (eg, change in fat mass, -2.9 kg [95% CI, -4.5 to -1.3 kg] vs 1.4 kg [95% CI, -0.3 to 3.1 kg]), cardiometabolic risk (eg, change in blood pressure, -6.5 mm Hg [95% CI, -10.3 to -2.6 mm Hg] vs 2.2 mm Hg [95% CI, -2.1 to 6.6 mm Hg]), and health-related quality of life (eg, change in Sleep Apnea Quality of Life Index, 0.8 points [95% CI, 0.5-1.1 points] vs 0.1 points [95% CI, -0.3 to 0.4 points]) were also found at the intervention end point.

CONCLUSIONS AND RELEVANCE

In this study, an interdisciplinary weight loss and lifestyle intervention involving Spanish men with moderate to severe OSA and had overweight or obesity and were receiving CPAP therapy resulted in clinically meaningful and sustainable improvements in OSA severity and comorbidities as well as health-related quality of life. This approach may therefore be considered as a central strategy to address the substantial impact of this increasingly common sleep-disordered breathing condition.

TRIAL REGISTRATION

ClinicalTrials.gov Identifier: NCT03851653.

Sleep Apnea Syndrome (SAS) Clinical Practice Guidelines 2020

The prevalence of sleep disordered breathing (SDB) is reportedly very high. Among SDBs, the incidence of obstructive sleep apnea (OSA) is higher than previously believed, with patients having moderate-to-severe OSA accounting for approximately 20% of adult males and 10% of postmenopausal women not only in Western countries but also in Eastern countries, including Japan. Since 1998, when health insurance coverage became available, the number of patients using continuous positive airway pressure (CPAP) therapy for sleep apnea has increased sharply, with the number of patients about to exceed 500,000 in Japan. Although the "Guidelines for Diagnosis and Treatment of Sleep Apnea Syndrome (SAS) in Adults" was published in 2005, a new guideline was prepared in order to indicate the standard medical care based on the latest trends, as supervised by and in cooperation with the Japanese Respiratory Society and the "Survey and Research on Refractory Respiratory Diseases and Pulmonary Hypertension" Group, of Ministry of Health, Labor and Welfare and other related academic societies, including the Japanese Society of Sleep Research, in addition to referring to the previous guidelines. Because sleep apnea is an interdisciplinary field covering many areas, this guideline was prepared including 36 clinical questions (CQs). In the English version, therapies and managements for SAS, which were written from CQ16 to 36, were shown. The Japanese version was published in July 2020 and permitted as well as published as one of the Medical Information Network Distribution Service (Minds) clinical practice guidelines in Japan in July 2021.

Obstructive sleep apnea

Obstructive sleep apnea (OSA) is a disease that results from loss of upper airway muscle tone leading to upper airway collapse during sleep in anatomically susceptible persons, leading to recurrent periods of hypoventilation, hypoxia, and arousals from sleep. Significant clinical consequences of the disorder cover a wide spectrum and include daytime hypersomnolence, neurocognitive dysfunction, cardiovascular disease, metabolic dysfunction, respiratory failure, and pulmonary hypertension. With escalating rates of obesity a major risk factor for OSA, the public health burden from OSA and its sequalae are expected to increase, as well. In this chapter, we review the mechanisms responsible for the development of OSA and associated neurocognitive and cardiometabolic comorbidities. Emphasis is placed on the neural control of the striated muscles that control the pharyngeal passages, especially regulation of hypoglossal motoneuron activity throughout the sleep/wake cycle, the neurocognitive complications of OSA, and the therapeutic options available to treat OSA including recent pharmacotherapeutic developments.

Sleep Apnea Syndrome (SAS) Clinical Practice Guidelines 2020

The prevalence of sleep-disordered breathing (SDB) is reportedly very high. Among SDBs, the incidence of obstructive sleep apnea (OSA) is higher than previously believed, with patients having moderate-to-severe OSA accounting for approximately 20% of adult males and 10% of postmenopausal women not only in Western countries but also in Eastern countries, including Japan. Since 1998, when health insurance coverage became available, the number of patients using continuous positive airway pressure (CPAP) therapy for sleep apnea has increased sharply, with the number of patients about to exceed 500,000 in Japan. Although the "Guidelines for Diagnosis and Treatment of Sleep Apnea Syndrome (SAS) in Adults" was published in 2005, a new guideline was prepared to indicate the standard medical care based on the latest trends, as supervised by and in cooperation with the Japanese Respiratory Society and the "Survey and Research on Refractory Respiratory Diseases and Pulmonary Hypertension" Group, of Ministry of Health, Labor and Welfare and other related academic societies, including the Japanese Society of Sleep Research, in addition to referring to the previous guidelines. Since sleep apnea is an interdisciplinary field covering many areas, this guideline was prepared including 36 clinical questions (CQs). In the English version, therapies and managements for SAS, which were written from CQ16 to 36, were shown. The Japanese version was published in July 2020 and permitted as well as published as one of the Medical Information Network Distribution Service (Minds) clinical practice guidelines in Japan in July 2021.

Low-Calorie Ketogenic Diet with Continuous Positive Airway Pressure to Alleviate Severe Obstructive Sleep Apnea Syndrome in Patients with Obesity Scheduled for Bariatric/Metabolic Surgery: a Pilot, Prospective, Randomized Multicenter Comparative Study

Obstructive sleep apnea syndrome (OSAS) and obesity are frequently associated with hypertension (HTN), dyslipidemia (DLP), and insulin resistance (IR). In patients with obesity and OSAS scheduled for bariatric surgery (BS), guidelines recommend at least 4 weeks of preoperative continuous positive airway pressure (CPAP). Low-calorie ketogenic diets (LCKDs) promote pre-BS weight loss (WL) and improve HTN, DLP, and IR. However, it is unclear whether pre-BS LCKD with CPAP improves OSAS more than CPAP alone. We assessed the clinical advantage of pre-BS CPAP and LCKD in patients with obesity and OSAS. Seventy patients with obesity and OSAS were randomly assigned to CPAP or CPAP+LCKD groups for 4 weeks. The effect of each intervention on the apnea–hypopnea index (AHI) was the primary endpoint. WL, C-reactive protein (CRP) levels, HTN, DLP, and IR were secondary endpoints. AHI scores improved significantly in both groups (CPAP, p=0.0231; CPAP+LCKD, p=0.0272). However, combining CPAP and LCKD registered no advantage on the AHI score (p=0.863). Furthermore, body weight, CRP levels, and systolic/diastolic blood pressure were significantly reduced in the CPAP+LCKD group after 4 weeks (p=0.0052, p=0.0161, p=0.0008, and p=0.0007 vs baseline, respectively), and CPAP+LCKD had a greater impact on CRP levels than CPAP alone (p=0.0329). The CPAP+LCKD group also registered a significant reduction in serum cholesterol, LDL, and triglyceride levels (p=0.0183, p=0.0198, and p<0.001, respectively). Combined with CPAP, LCKD-induced WL seems to not have a significant incremental effect on AHI, HTN, DLP, and IR but lower CRP levels demonstrated a positive impact on chronic inflammatory status.

Obstructive sleep apnea and stroke: The mechanisms, the randomized trials, and the road ahead

When considered separately from cardiovascular disease, stroke is the third leading cause of death in the U.S. and is the leading cause of long-term disability in adults. New approaches that can be offered to the majority of ischemic stroke patients, can be continued throughout post-stroke care, can limit stroke severity, and can complement or even enhance rehabilitation, would transform ischemic stroke recovery. The treatment of obstructive sleep apnea (OSA) in patients with acute ischemic stroke may represent one such approach. This manuscript reviews the epidemiologic studies of the bidirectional association between OSA and stroke, and the mechanisms and molecular signatures of OSA leading to transient ischemic attack and stroke as well as the randomized controlled trials and observational cohort studies examining continuous positive airway treatment efficacy on the impact of stroke outcomes. Finally, the insights these studies provide on future research are also discussed.

Impact of continuous positive airway pressure ventilation on cardiovascular outcomes among patients with obstructive sleep apnea: A meta-analysis of randomized trials

Background

The impact of continuous positive airway pressure (CPAP) on cardiovascular outcomes among patients with obstructive sleep apnea (OSA) is controversial.

Objective

To evaluate the impact of CPAP on reducing cardiovascular outcomes in patients with OSA.

Methods

We performed a computerized search of MEDLINE, EMBASE and COCHRANE databases through April 2021 for randomized trials evaluating the impact of CPAP versus control on cardiovascular outcomes in patients with OSA. Summary estimates were reported using both fixed and random effects model. The main study outcome was major adverse cardiac events (MACE).

Results

The final analysis included 8 randomized trials with total of 5684 patients. The weighted mean follow-up was 42.6 months. There was no difference between the CPAP and control groups in the risk of MACE (14.4% versus 14.8%, risk ratio [RR]: 0.97; 95% confidence interval [CI]: 0.85 to 1.10; p = 0.60; I2 = 21%). Subgroup analysis suggested that CPAP was associated with lower MACE (by 36%) in CPAP-adherent patients (≥4 h/night) (Pinteraction = 0.08). There was no difference between the CPAP and control groups in the risk of all-cause mortality, cardiovascular mortality, acute stroke, acute myocardium infarction or hospitalizations for angina.

Conclusions and relevance

CPAP use might not be associated with lower cardiovascular events among patients with OSA. However, patients adherent to CPAP (≥4 h/night) might derive a benefit on cardiovascular outcomes. Future studies are warranted to evaluate the impact of CPAP in reducing cardiovascular events among patients with severe OSA and with optimal adherence rates to CPAP therapy.

OSA patients not treated with PAP - Evolution over 5 years according to the Baveno classification and cardiovascular outcomes

INTRODUCTION

The evolution of patients with obstructive sleep apnea (OSA) non-eligible for PAP-therapy at diagnosis is unknown. Currently, the severity of OSA is based on the apnea-hypopnea index (AHI), but its prognostic relevance has raised concerns. The Baveno classification may allow a better stratification of severity and therapeutic guidance in OSA.

METHODS

Patients with AHI≥5/h in 2015, classified into Baveno groups A and B and non-eligible for PAP therapy at diagnosis and over 5 years, were analyzed. Patients were reclassified into Baveno groups (A-D) and changes in groups over 5 years were explored. Patients in Baveno groups C and D, who developed major cardiovascular comorbidities (CVC) or end-organ damage (EOD group), were compared with patients in Baveno groups A and B (non-EOD group). To identify predictors of the development of major CVC or EOD, a logistic regression analysis was performed.

RESULTS

There were 76 patients, 58% male, mean age 51.9 ± 10.1 years, mean body mass index (BMI) of 30.3 ± 5.0 kg/m2 and median AHI of 8.9 (5.9-12.0) events/h. At diagnosis, 46% and 54% of patients were classified into Baveno group A and group B, respectively. In total, 21% of patients developed major CVC or EOD (Baveno group C or D); higher age (p = 0.011) and BMI (p = 0.004) and a higher percentage of central apneas (p = 0.012) at diagnosis significantly predicted it, while sex, sleepiness, insomnia, AHI, ODI and T90 were not.

CONCLUSIONS

A significant percentage of patients non-eligible for PAP-therapy at diagnosis of OSA developed CVC or EOD; higher age and BMI and a higher percentage of central apneas were significant predictors.

Positionspapier „Schlafmedizin in der Kardiologie“, Update 2021

Es hat sich viel getan in der Welt der Schlafmedizin in der Kardiologie, weshalb eine vollwertige Überarbeitung des Positionspapiers „Schlafmedizin in der Kardiologie“ erforderlich wurde. In der aktuellen neuartigen Version finden sich nicht nur alle verfügbaren Studien, Literaturstellen und Updates zu Pathophysiologie, Diagnostik- und Therapieempfehlungen, sondern auch Ausblicke auf neue Entwicklungen und zukünftige Forschungserkenntnisse. Dieses überarbeitete Positionspapier gibt Empfehlungen für Diagnostik und Therapie von Patienten mit kardiovaskulären Erkrankungen mit schlafassoziierten Atmungsstörungen und erteilt darüber hinaus einen fundierten Überblick über verfügbare Therapien und Evidenzen, gibt aber ebenso Ratschläge wie mit Komorbiditäten umzugehen ist. Insbesondere enthält dieses überarbeitete Positionspapier aktualisierte Stellungnahmen zu schlafassoziierten Atmungsstörungen bei Patienten mit koronarer Herzerkrankung, Herzinsuffizienz, arterieller Hypertonie, aber auch für Patienten mit Vorhofflimmern. Darüber hinaus finden sich erstmals Empfehlungen zur Telemedizin als eigenes, neues Kapitel. Dieses Positionspapier bietet Kardiologen sowie Ärzten in der Behandlung von kardiovaskulären Patienten die Möglichkeit einer evidenzbasierten Behandlung der wachsend bedeutsamen und mit zunehmender Aufmerksamkeit behafteten Komorbidität schlafassoziierter Atmungsstörungen. Und nicht zuletzt besteht mit diesem neuen Positionspapier eine enge Verknüpfung mit dem neuen Curriculum Schlafmedizin der Deutschen Gesellschaft für Kardiologie, weshalb dieses Positionspapier eine Orientierung für die erworbenen Fähigkeiten des Curriculums im Umgang von kardiovaskulären Patienten mit schlafassoziierten Atmungsstörungen darstellt.

Symptomatic response to CPAP in obstructive sleep apnea versus COPD- obstructive sleep apnea overlap syndrome: Insights from a large national registry

Background

The symptomatic response to continuous positive airway pressure (CPAP) therapy in COPD-obstructive sleep apnea overlap syndrome (OVS) compared to OSA syndrome (OSA) alone has not been well studied so far. The aim of this study is to explore main differences in the clinical response to CPAP treatment in OVS compared to OSA alone.

Study design and methods

Using prospective data from the French National Sleep Apnea Registry, we conducted an observational study among 6320 patients with moderate-to-severe OSA, available spirometry, and at least one follow-up visit under CPAP therapy.

Results

CPAP efficacy measured on the residual apnea-hypopnea index and median adherence were similar between OVS and OSA patients. In both groups, the overall burden of symptoms related to sleep apnea improved with CPAP treatment. In a multivariable model adjusted for age, gender, body mass index, adherence to treatment and residual apnea-hypopnea index, OVS was associated with higher odds for persistent morning headaches (OR: 1.37 [95% CI; 1.04; 1.79]; P = 0.02), morning tiredness (OR: 1.33 [95% CI: 1.12; 1.59]; P<0.01), daytime sleepiness (OR; 1.24 [95% CI: 1.4; 1.46]: P<0.01) and exertional dyspnea (OR: 1.26 [95% CI: 1.00;1.58]; P = 0.04) when compared with OSA alone.

Interpretation

CPAP therapy was effective in normalizing the apnea-hypopnea index and significantly improved OSA-related symptoms, regardless of COPD status. CPAP should be offered to patients with OVS on a trial basis as a significant improvement in OSA-related symptoms can be expected, although the range of response may be less dramatic than in OSA alone.

Referral of adults with obstructive sleep apnea for surgical consultation: an American Academy of Sleep Medicine systematic review, meta-analysis, and GRADE assessment

INTRODUCTION

This systematic review provides supporting evidence for the accompanying clinical practice guideline on the referral of adults with obstructive sleep apnea (OSA) for surgical consultation.

METHODS

The American Academy of Sleep Medicine commissioned a task force of experts in sleep medicine. A systematic review was conducted to identify studies that compared the use of upper airway sleep apnea surgery or bariatric surgery to no treatment as well as studies that reported on patient-important and physiologic outcomes pre- and postoperatively. Statistical analyses were performed to determine the clinical significance of using surgery to treat obstructive sleep apnea in adults. Finally, the Grading of Recommendations Assessment, Development, and Evaluation (GRADE) process was used to assess the evidence for making recommendations.

RESULTS

The literature search resulted in 274 studies that provided data suitable for statistical analyses. The analyses demonstrated that surgery as a rescue therapy results in a clinically significant reduction in excessive sleepiness, snoring, blood pressure (BP), apnea-hypopnea index (AHI), respiratory disturbance index (RDI), oxygen desaturation index (ODI), increase in lowest oxygen saturation (LSAT), sleep quality, and improvement in quality of life in adults with OSA who are intolerant or unaccepting of positive airway pressure (PAP) therapy. The analyses demonstrated that surgery as an adjunctive therapy results in a clinically significant reduction in optimal PAP pressure and improvement in PAP adherence in adults with OSA who are intolerant or unaccepting of PAP due to side effects associated with high pressure requirements. The analyses also demonstrated that surgery as an initial treatment results in a clinically significant reduction in AHI/RDI, sleepiness, snoring, BP, and ODI, and increase in LSAT in adults with OSA and major anatomical obstruction. Analysis of bariatric surgery data showed a clinically significant reduction in BP, AHI/RDI, sleepiness, snoring, optimal PAP level, BMI, ODI, and an increase in LSAT in adults with OSA and obesity. Analyses of very limited evidence suggest that upper airway surgery does not result in a clinically significant increase in risk of serious persistent adverse events and suggested that bariatric surgery may result in a clinically significant risk of iron malabsorption that may be managed with iron supplements. The task force provided a detailed summary of the evidence along with the quality of evidence, the balance of benefits and harms, patient values and preferences, and resource use considerations.

Period-to-Period Variability of Moderate/Severe Obstructive Sleep Apnoea

INTRODUCTION

The severity of obstructive sleep apnoea (OSA) is highly variable on a night-to-night basis. Patients are commonly categorised based on the severity of their OSA, and this is then used to influence management and reimbursement, including continuous positive airway pressure (CPAP). We aimed to establish to what extent the OSA severity category changes during two periods of OSA, based on mean and maximum oxygen desaturation index (ODI).

METHODS

Patients with a diagnosis of moderate to severe OSA who had been on CPAP for greater than 1 year were included in this study. Subjects underwent two periods of CPAP withdrawal for four nights each.

RESULTS

Twenty-five patients completed the study. Based on the mean ODI of the four nights, 14 (56%) patients changed OSA severity categorisation, with three (12%) changing category to mild. Based on the maximum ODI of the four nights, nine (36%) patients changed OSA severity categorisation, with one (4%) changing category to mild. One third to a half of patients' OSA severity category changed between the two periods of four night's CPAP withdrawal.

CONCLUSIONS

OSA is highly variable on a period-to-period basis as well as on a night-to-night basis. We believe the concept of patients having a definable and 'real' level of OSA severity is therefore flawed. OSA severity should be based mainly on symptoms, as these are the dominant reasons for treatment, and the sleep study should be used qualitatively to ascertain whether respiratory events are the likely cause of the symptoms.

TRIAL REGISTRATION

ISRCTN17987510.

Randomized clinical trials of cardiovascular disease in obstructive sleep apnea: understanding and overcoming bias

Three recent randomized control trials (RCTs) found that treatment of obstructive sleep apnea (OSA) with continuous positive airway pressure (CPAP) did not reduce rates of future cardiovascular events. This article discusses the biases in these RCTs that may explain their negative results, and how to overcome these biases in future studies. First, sample selection bias affected each RCT. The subjects recruited were not patients typically presenting for treatment of OSA. In particular, subjects with excessive sleepiness were excluded due to ethical concerns. As recent data indicate that the excessively sleepy OSA subtype has increased cardiovascular risk, subjects most likely to benefit from treatment were excluded. Second, RCTs had low adherence to therapy. Reported adherence is lower than found clinically, suggesting it is in part related to selection bias. Each RCT showed a CPAP benefit consistent with epidemiological studies when restricting to adherent patients, but was underpowered. Future studies need to include sleepy individuals and maximize adherence. Since it is unethical and impractical to randomize very sleepy subjects to no therapy, alternative designs are required. Observational designs using propensity scores, which are accepted by FDA for studies of medical devices, provide an opportunity. The design needs to ensure covariate balance, including measures assessing healthy user and healthy adherer biases, between regular users of CPAP and non-users. Sensitivity analyses can evaluate the robustness of results to unmeasured confounding, thereby improving confidence in conclusions. Thus, these designs can robustly assess the cardiovascular benefit of CPAP in real-world patients, overcoming biases in RCTs.

The impact of sleep disorders on microvascular complications in patients with type 2 diabetes (SLEEP T2D): the protocol of a cohort study and feasibility randomised control trial

BACKGROUND

Obstructive sleep apnoea (OSA) is very common in patients with type 2 diabetes (T2D). We and others have shown that OSA was associated with diabetes-related microvascular complications in patients with T2D in cross-sectional and longitudinal studies and that compliance with continuous positive airway pressure (CPAP) reduced the progression of microvascular complications. Hence, we hypothesised that adequate CPAP reduces the development of microvascular complication in patients with T2D.

METHODS

SLEEP T2D is a cohort study with embedded feasibility, open-label, parallel-arm, randomised control trial (RCT) over 2 years. The primary aim is the feasibility of conducting a definitive RCT assessing the impact of CPAP on chronic kidney disease and other microvascular complications in patients with T2D. The main parameters are to assess willingness of participants to be randomised, follow-up rates, CPAP adherence/compliance, to optimise the choice of outcome measures for a substantive trial, and to identify the parameters for sample size calculations. The secondary aims of the study are related to the impact of CPAP, sleep-related disorders, and sleep chronotype on a variety of diabetes-related end points. The study participants were recruited from the T2D services in multiple NHS trusts across England. The main exclusion criteria for the cohort study are as follows: T1D, eGFR < 15 mL/min/1.73 m², known OSA, active malignancy or chronic kidney disease from reasons other than diabetes, pregnancy, professional drivers, and a history of falling asleep whilst driving within last 2 years. The main exclusion criteria from the RCT were as follows: Apnoea-Hypopnoea Index < 10 and Epworth Sleepiness Score ≥ 11. Study participants were extensively phenotyped clinically and biochemically. The OSA diagnosis was based on multichannel portable device (ApneaLink Air^TM, Resmed).

DISCUSSION

The feasibility RCT will help us design the future RCT to assess the impact of CPAP on diabetes-related microvascular complications. The cohort study will generate preliminary data regarding the impact of sleep quality, duration, and chronotype on diabetes-related outcomes which could lead to further mechanistic and interventional studies.

TRIAL REGISTRATION

ISRCTN, ISRCTN12361838 . Registered 04 April 2018, Protocol version: v5.0 02.12.19.

Impact of continuous positive airway pressure mode on adherence to treatment in obstructive sleep apnea patients awaiting bariatric surgery

Obstructive sleep apnea is prevalent in the bariatric population, and is associated with various complications. Despite increasing popularity, automatic positive airway pressure has not yet been studied in this population. The objective was to compare treatment adherence between automatic positive airway pressure and fixed positive airway pressure (continuous positive airway pressure) in obstructive sleep apnea patients awaiting bariatric surgery. This randomized controlled trial involved obese patients newly diagnosed with severe obstructive sleep apnea and awaiting bariatric surgery. The primary outcome was the difference in adherence between automatic positive airway pressure and continuous positive airway pressure pre-operatively. Secondary outcomes included positive airway pressure efficacy, adherence at 1 month, adverse effects, quality of life and peri-operative complications. Analyses were conducted using a modified intention-to-treat methodology. Fifty patients were randomized. Baseline characteristics and duration of positive airway pressure therapy were comparable between groups. At the time of surgery, the percentage of overall nights positive airway pressure used was 96.9% [95% confidence interval: 93.5-100] and 86.0% [95% confidence interval: 66.9-100] in the automatic positive airway pressure and continuous positive airway pressure groups, respectively (p = .047). Average use was 6.3 hr per night [95% confidence interval: 5.1-7.2] and 5.9 hr per night [95% confidence interval: 3.0-8.8], with a difference of 0.4 hr favouring automatic positive airway pressure (p = .75). Nightly use ≥ 4 hr per night was 86.4% and 74.0% in the automatic positive airway pressure and fixed continuous positive airway pressure groups, respectively (p = .22). There were no statistically significant differences regarding adherence at 1 month, efficacy parameters, adverse effects, quality of life and peri-operative complications. With no difference on the safety profile and efficiency parameters, treatment adherence is not improved with automatic positive airway pressure compared with fixed continuous positive airway pressure in obstructive sleep apnea patients awaiting bariatric surgery.

Where to Next for Optimizing Adherence in Large-Scale Trials of Continuous Positive Airway Pressure?

Large-scale randomized trials of positive airway pressure (PAP) efficacy have been largely negative but PAP adherence was notably suboptimal across the trials. To address this limitation, evidence-based PAP adherence protocols embedded within the larger trial protocol are recommended. The complexity of such protocols depends on adequacy of resources, including funding and inclusion of behavioral scientist experts on the scientific team, and trial-specific considerations (eg, target population) and methods. Recommendations for optimizing PAP adherence in large-scale trials are set forth that address rigor and reproducibility.

Effect of CPAP on cardiovascular events in minimally symptomatic OSA: long-term follow-up of the MOSAIC randomised controlled trial

The effect of continuous positive airway pressure (CPAP) on cardiovascular events is uncertain in minimally symptomatic obstructive sleep apnoea. Previous 2-year follow-up data from the Multicentre Obstructive Sleep Apnoea Intervention Cardiovascular (MOSAIC) trial showed a marginal reduction in cardiovascular events with CPAP therapy. We now present long-term MOSAIC study follow-up data. Median (first quartile, third quartile) follow-up was 5.0 (2.2, 5.0) and 3.7 (1.5, 5.0) years for CPAP and standard care, respectively. Compared to standard care, CPAP had no statistically significant effect on the risk of cardiovascular events (HR=0.83, p=0.54, 95% CI 0.46–1.51).

Randomised, cOntrolled Multicentre trial of 26 weeks subcutaneous liraglutide (a glucagon-like peptide-1 receptor Agonist), with or without contiNuous positive airway pressure (CPAP), in patients with type 2 diabetes mellitus (T2DM) and obstructive sleep apnoEa (OSA) (ROMANCE): study protocol assessing the effects of weight loss on the apnea-hypnoea index (AHI)

INTRODUCTION

Obstructive sleep apnoea (OSA) and type 2 diabetes mellitus (T2DM) often occur concurrently, and untreated OSA may potentially amplify the high risk of cardiovascular disease in T2DM. Compliance with continuous positive airway pressure (CPAP), the conventional treatment for OSA, can be poor and considering weight loss is the most effective treatment for OSA. This trial examines whether the glucagon-like peptide-1 receptor agonist liraglutide, a glucose-lowering therapy associated with significant weight loss used in T2DM, can improve the severity and symptoms of OSA.

METHODS AND ANALYSIS

This is an outpatient, single-centred, open-labelled, prospective, phase IV randomised controlled trial in a two-by-two factorial design. One hundred and thirty-two patients with newly diagnosed OSA (apnoea-hypopnoea index (AHI) ≥15 events/hour), and existing obesity and T2DM (glycated haemoglobin (HbA_1c) ≥47 mmol/mol), will be recruited from diabetes and sleep medicine outpatient clinics in primary and secondary care settings across Liverpool. Patients will be allocated equally, using computer-generated random, permuted blocks of unequal sizes, to each of the four treatment arms for 26 weeks: (i) liraglutide (1.8 mg once per day) alone, (ii) liraglutide 1.8 mg once per day with CPAP, (iii) CPAP alone (conventional care) or (iv) no treatment (control). The primary outcome measure is change in OSA severity, determined by AHI. Secondary outcome measures include effects on glycaemic control (glycated haemoglobin (HbA1c)), body weight and quality of life measures. Exploratory measures include measures of physical activity, MRI-derived measures of regional body composition including fat mass (abdominal subcutaneous, visceral, neck and liver fat) and skeletal muscle mass (cross-sectional analysis of thigh), indices of cardiac function (using transthoracic echocardiography) and endothelial function.

ETHICAL APPROVAL

The study has been approved by the North West Liverpool Central Research Ethics Committee (14/NW/1019) and it is being conducted in accordance with the Declaration of Helsinki and Good Clinical Practice.

TRIAL REGISTRATION NUMBERS

ISRCTN16250774. EUDRACT No. 2014-000988-41. UTN U1111-1139-0677.

Advances and challenges in pursuing biomarkers for obstructive sleep apnea: Implications for the cardiovascular risk

Obstructive sleep apnea (OSA) is a common clinical condition associated with increased cardiovascular morbidity and mortality. Recent evidence from clinical studies and animal models suggest that OSA can promote cardiovascular disease by inducing autonomic, hemodynamic, inflammatory and metabolic dysregulation. However, most of the evidence addressing hard endpoints in humans is derived from observational studies. Several challenges have been noted in the pursuit of a comprehensive knowledge base about the impact of OSA including: 1) the precise mechanisms by which OSA causes metabolic and cardiovascular consequences are not clear, which limits our current ability to address potential targets in OSA; 2) several patients with OSA, even with severe forms, present with no or mild daytime symptoms. Beyond the obvious challenges for obtaining good adherence for conventional OSA treatments, there is evidence that symptomatic vs. asymptomatic patients with OSA do not necessarily have the same metabolic and cardiovascular outcomes; and 3) the cardiovascular response to OSA treatment may vary even in those patients with good adherence. In this scenario, there is an obvious need to develop biomarkers in the OSA research area. This review focuses on describing the advances that have occurred so far in exploring potential OSA biomarkers with clear emphasis for the cardiovascular risk. Particular attention will be devoted to discuss molecular biomarkers including the potential role of microRNAs, proteomics and metabolomics. We also discuss the major challenges and perspectives in this growing research field.

Obstructive sleep apnoea treatment and blood pressure: which phenotypes predict a response? A systematic review and meta-analysis

The treatment for obstructive sleep apnoea (OSA) with continuous positive airway pressure (CPAP) or mandibular advancement devices (MADs) is associated with blood pressure (BP) reduction; however, the overall effect is modest. The aim of this systematic review and meta-analysis of randomised controlled trials (RCTs) comparing the effect of such treatments on BP was to identify subgroups of patients who respond best to treatment.The article search was performed in three different databases with specific search terms and selection criteria. From 2289 articles, we included 68 RCTs that compared CPAP or MADs with either passive or active treatment. When all the studies were pooled together, CPAP and MADs were associated with a mean BP reduction of -2.09 (95% CI -2.78- -1.40) mmHg for systolic BP and -1.92 (95% CI -2.40- -1.43) mmHg for diastolic BP and -1.27 (95% CI -2.34- -0.20) mmHg for systolic BP and -1.11 (95% CI -1.82- -0.41) mmHg for diastolic BP, respectively. The subgroups of patients who showed a greater response were those aged <60 years (systolic BP -2.93 mmHg), with uncontrolled BP at baseline (systolic BP -4.14 mmHg) and with severe oxygen desaturations (minimum arterial oxygen saturation measured by pulse oximetry <77%) at baseline (24-h systolic BP -7.57 mmHg).Although this meta-analysis shows that the expected reduction of BP by CPAP/MADs is modest, it identifies specific characteristics that may predict a pronounced benefit from CPAP in terms of BP control. These findings should be interpreted with caution; however, they are particularly important in identifying potential phenotypes associated with BP reduction in patients treated for OSA.

Continuous positive airway pressure can improve depression in patients with obstructive sleep apnoea syndrome: a meta-analysis based on randomized controlled trials

Objective

Substantial research indicates a clear relationship between obstructive sleep apnoea syndrome (OSAS) and depression. The study aim was to quantitatively evaluate whether continuous positive airway pressure (CPAP) therapy improves mood symptoms in OSAS patients.

Methods

PubMed and Embase databases were systematically searched up to 2017 for publications on the impact of CPAP on mood symptoms in OSAS patients.

Results

For the final analysis, nine randomized controlled trials comprising 1,052 patients were selected. The pooled standard mean difference (SMD) of the effect of CPAP on depression was 0.31 (95% confidence interval 0.18, 0.43). A subgroup analysis showed that when CPAP use was greater than 4 hours per night, it tended to be effective in improving patients’ mood symptoms (SMD = 0.38; confidence interval 0.23, 0.54). Analysis of publication bias using Egger’s test found no evidence of publication bias.

Conclusion

CPAP treatment can improve depression in OSAS patients.

Nocturnal bilevel positive airway pressure for the treatment of asthma

Nocturnal worsening of asthma may be due to reduced lung volumes and fewer sigh breaths, which have been shown to increase airway resistance and bronchoreactivity. We hypothesized that mimicking deep inspiration using nocturnal mechanical support would improve symptoms in patients with asthma. Subjects with asthma underwent usual care and bilevel positive airway pressure (PAP) therapy for 4 weeks, separated by 4 weeks, and methacholine challenge (PC20) and subjective assessments. 13 patients with asthma alone and 8 with asthma + OSA completed the protocol. Change in bronchoreactivity (ratio of Post/Pre PC20) was not significantly different during usual care and bilevel PAP [0.86 (IQR 0.19, 1.82) vs 0.94 (IQR 0.56, 2.5), p = 0.88], nor was the change in Asthma Control Test different: 0.1 ± 2.2 vs. -0.2 ± 2.9, p = 0.79, respectively. Bilevel PAP therapy for four weeks did not improve subjective or objective measures of asthma severity in patients with asthma or those with asthma and OSA, although there was heterogeneity in response.

Obstructive sleep apnea and dyslipidemia: from animal models to clinical evidence

Lipid metabolism deregulation constitutes the pathogenic basis for the development of atherosclerosis and justifies a high incidence of cardiovascular-related morbidity and mortality. Some data suggest that dyslipidemia may be associated with sleep-disordered breathing, mainly obstructive sleep apnea (OSA), due to alterations in fundamental biochemical processes, such as intermittent hypoxia (IH). The aim of this systematic review was to identify and critically evaluate the current evidence supporting the existence of a possible relationship between OSA and alterations in lipid metabolism. Much evidence shows that, during the fasting state, OSA and IH increase lipid delivery from the adipose tissue to the liver through an up-regulation of the sterol regulatory element-binding protein-1 and stearoyl-CoA desaturase-1, increasing the synthesis of cholesterol esters and triglycerides. In the postprandial state, lipoprotein clearance is delayed due to lower lipoprotein lipase activity, probably secondary to IH-up-regulation of angiopoietin-like protein 4 and decreased activity of the peroxisome proliferator-activated receptor alpha. Moreover, oxidative stress can generate dysfunctional oxidized lipids and reduce the capacity of high-density lipoproteins (HDL) to prevent low-density lipoprotein (LDL) oxidation. In the clinical field, several observational studies and a meta-regression analysis support the existence of a link between OSA and dyslipidemia. Although there is evidence of improved lipid profile after apnea-hypopnea suppression with continuous positive airway pressure (CPAP), the majority of the data come from observational studies. In contrast, randomized controlled trials evaluating the effects of CPAP on lipid metabolism present inconclusive results and two meta-analyses provide contradictory evidence.

Ten-year adherence to continuous positive airway pressure treatment in patients with moderate-to-severe obstructive sleep apnea

Purpose

This study aimed to evaluate the 10-year adherence to and identify the predictors of dropout from continuous positive airway pressure (CPAP) treatment for patients with moderate-to-severe obstructive sleep apnea (OSA).

Methods

We retrospectively analyzed the continuity, dropout, or other behaviors of 181 patients who initiated CPAP treatment at the Tokyo Dental College Ichikawa General Hospital from January 2003 to June 2005.

Results

Among a total of 181 patients, 56 (30.9%) dropped out of the treatment. Among the 125 patients who did not dropout, 54 continued CPAP treatment for > 10 years, 16 completed the treatment with OSA improvement, and 7 could not complete the treatment owing to unavoidable reasons such as death, dementia, hospitalization for serious illness, or migration to other countries. Further, 47 patients moved to another facility, whereas 1 patient purchased a CPAP device and stopped visiting our facility. Among the 56 patients who dropped out, approximately 50% of the patients dropped out within a year, and all dropped out within 76 months. Comparing demographics, OSA parameters, and CPAP parameters between the patients who did and did not drop out of the treatment, Cox regression analysis indicated that body mass index (BMI) and the first-month utilization rate were clinical variables that were independently associated with discontinuation of CPAP treatment.

Conclusion

The results of this study show that BMI and the first-month utilization rate of CPAP treatment are the predictors of the long-term adherence to this treatment.

Electronic supplementary material

The online version of this article (10.1007/s11325-020-02033-0) contains supplementary material, which is available to authorized users.

Development and validation of a Chinese version of the Sleep Apnea Quality of Life Index

OBJECTIVE

A Chinese version of the Sleep Apnea Quality of Life Index (SAQLI) for patients with obstructive sleep apnea (OSA) undergoing treatment with continuous positive airway pressure (CPAP) was developed and validated. No Chinese versions of the SAQLI have been previously validated.

METHODS

A convenience sample of 78 patients with OSA who received CPAP therapy at a Taiwanese teaching hospital was enrolled. The SAQLI is organized into four domains: daily functioning, social interactions, emotional functioning, and symptoms. This study evaluated the equivalence (forward translation and back translation), validity, and reliability of a Chinese version of the SAQLI.

RESULTS

The content validity index (CVI) values of the daily functioning, social interactions, emotional functioning, and symptom domains were .93, .93, .96, and 1.00, respectively. Construct validity of one factor was generated by exploratory factor analysis, and the factor explained the following: (A) daily functioning 54%, (B) social interactions 59%, (C) emotional functioning 64%, and (D) symptoms 75% of total explained variance. The Cronbach's α internal consistency values for the daily functioning, social interactions, emotional functioning, and symptom domains were 0.68, 0.94, 0.93, and 0.92, respectively. The repeatability of the SAQLI at 7 days and 30 days after the first administration showed reliability coefficients of .94 and .93 (p = 0.001), respectively.

CONCLUSIONS

The results indicate that the Chinese version of the SAQLI has good reliability and validity, as well as refined indicators for assessing the tool's accuracy. Clinicians may thus use the scale to examine the quality of life in Chinese-speaking patients with OSA undergoing CPAP therapy.

Assessment of Mandibular Movement Monitoring With Machine Learning Analysis for the Diagnosis of Obstructive Sleep Apnea

IMPORTANCE

Given the high prevalence of obstructive sleep apnea (OSA), there is a need for simpler and automated diagnostic approaches.

OBJECTIVE

To evaluate whether mandibular movement (MM) monitoring during sleep coupled with an automated analysis by machine learning is appropriate for OSA diagnosis.

DESIGN, SETTING, AND PARTICIPANTS

Diagnostic study of adults undergoing overnight in-laboratory polysomnography (PSG) as the reference method compared with simultaneous MM monitoring at a sleep clinic in an academic institution (Sleep Laboratory, Centre Hospitalier Universitaire Université Catholique de Louvain Namur Site Sainte-Elisabeth, Namur, Belgium). Patients with suspected OSA were enrolled from July 5, 2017, to October 31, 2018.

MAIN OUTCOMES AND MEASURES

Obstructive sleep apnea diagnosis required either evoking signs or symptoms or related medical or psychiatric comorbidities coupled with a PSG-derived respiratory disturbance index (PSG-RDI) of at least 5 events/h. A PSG-RDI of at least 15 events/h satisfied the diagnosis criteria even in the absence of associated symptoms or comorbidities. Patients who did not meet these criteria were classified as not having OSA. Agreement analysis and diagnostic performance were assessed by Bland-Altman plot comparing PSG-RDI and the Sunrise system RDI (Sr-RDI) with diagnosis threshold optimization via receiver operating characteristic curves, allowing for evaluation of the device sensitivity and specificity in detecting OSA at 5 events/h and 15 events/h.

RESULTS

Among 376 consecutive adults with suspected OSA, the mean (SD) age was 49.7 (13.2) years, the mean (SD) body mass index was 31.0 (7.1), and 207 (55.1%) were men. Reliable agreement was found between PSG-RDI and Sr-RDI in patients without OSA (n = 46; mean difference, 1.31; 95% CI, -1.05 to 3.66 events/h) and in patients with OSA with a PSG-RDI of at least 5 events/h with symptoms (n = 107; mean difference, -0.69; 95% CI, -3.77 to 2.38 events/h). An Sr-RDI underestimation of -11.74 (95% CI, -20.83 to -2.67) events/h in patients with OSA with a PSG-RDI of at least 15 events/h was detected and corrected by optimization of the Sunrise system diagnostic threshold. The Sr-RDI showed diagnostic capability, with areas under the receiver operating characteristic curve of 0.95 (95% CI, 0.92-0.96) and 0.93 (95% CI, 0.90-0.93) for corresponding PSG-RDIs of 5 events/h and 15 events/h, respectively. At the 2 optimal cutoffs of 7.63 events/h and 12.65 events/h, Sr-RDI had accuracy of 0.92 (95% CI, 0.90-0.94) and 0.88 (95% CI, 0.86-0.90) as well as posttest probabilities of 0.99 (95% CI, 0.99-0.99) and 0.89 (95% CI, 0.88-0.91) at PSG-RDIs of at least 5 events/h and at least 15 events/h, respectively, corresponding to positive likelihood ratios of 14.86 (95% CI, 9.86-30.12) and 5.63 (95% CI, 4.92-7.27), respectively.

CONCLUSIONS AND RELEVANCE

Automatic analysis of MM patterns provided reliable performance in RDI calculation. The use of this index in OSA diagnosis appears to be promising.

Association between Upper-airway Surgery and Ameliorative Risk Markers of Endothelial Function in Obstructive Sleep Apnea

The objective of our study was to evaluate the effects of upper-airway surgery on improvement of endothelial function-related markers in patients with obstructive sleep apnea (OSA). Subjects with moderate to severe OSA who underwent upper-airway surgery, with a follow-up duration of at least 6 months, were included. Pre- and postoperative polysomnographic variables and endothelial function-related markers were compared. Subgroup and correlation analyses were conducted to find possible indicators for better endothelial function-related markers after upper-airway surgery. In total, 44 patients with OSA were included. The mean follow-up duration was 1.72 ± 0.92 years. Serum VEGFA [-20.29 (CI: -35.27, -5.31), p < 0.05], Ang2 [-0.06 (CI: -0.16, 0.03), p < 0.05], E-selectin [-7.21 (CI: -11.01, -3.41), p < 0.001], VWF [-58.83 (CI: -103.93, -13.73), p < 0.05], VWFCP [-33.52 (CI: -66.34, -0.70), p < 0.05], and TM [-0.06 (CI: -0.09, -0.03), p < 0.05] were significantly lower after upper-airway surgery. However, other risk markers of endothelial function, such as Ang1, ICAM1, VEGFR1, and VCAM, did not change significantly. Correlations between improved endothelial function-related markers and ameliorated oxyhemoglobin saturation and glucolipid metabolism were established. Upper-airway surgery might be associated with an improvement in endothelial function in patients with OSA. These changes may be associated with improved oxygen saturation after upper-airway surgery.