Challenges in obstructive sleep apnoea

CPAP resumption after a first termination and impact on all-cause mortality in France

BACKGROUND

Continuation of continuous positive airway pressure (CPAP) therapy after initial prescription has been shown to reduce all-cause mortality versus therapy termination. However, there is a lack of data on the rates and impact of resuming CPAP in patients with obstructive sleep apnoea (OSA). This analysis determined the prevalence of CPAP resumption in the year after termination, characterised determinants of CPAP resumption, and examined the impact of CPAP resumption on all-cause mortality.

METHODS

French national health insurance reimbursement system data for adults aged ≥18 years were used. CPAP prescription was identified by specific treatment codes. Patients who resumed CPAP after first therapy termination and continued to use CPAP for 1 year were matched with those who resumed CPAP then terminated therapy for a second time.

RESULTS

Out of 103 091 individuals with a first CPAP termination, 26% resumed CPAP over the next 12 months, and 65% of these were still using CPAP 1 year later. Significant predictors of CPAP continuation after resumption included male sex, hypertension and CPAP prescription by a pulmonologist. In the matched population, the risk of all-cause death was 38% lower in individuals who continued using CPAP after therapy resumption versus those who had a second therapy discontinuation (hazard ratio 0.62, 95% CI 0.48-0.79; p=0.0001).

CONCLUSION

These data suggest that individuals with OSA who fail initial therapy with CPAP should be offered a second trial with the device to ensure that effective therapy is not withheld from those who might benefit.

Clinical Application of the Multicomponent Grading System for Sleep Apnea Classification and Incident Cardiovascular Mortality

Objective  To evaluate the clinical utility of the Baveno classification in predicting incident cardiovascular mortality after five years of follow-up in a clinic-based cohort of patients with obstructive sleep apnea (OSA). Materials and Methods  We evaluated the reproducibility of the Baveno classification using data from the Santiago Obstructive Sleep Apnea (SantOSA) study. The groups were labeled Baveno A (minor symptoms and comorbidities), B (severe symptoms and minor comorbidities), C (minor symptoms and severe comorbidities), and D (severe symptoms and comorbidities). Within-group comparisons were performed using analysis of variance (ANOVA) and post hoc tests. The associations between groups and incident cardiovascular mortality were determined through the Mantel-Cox and Cox proportional hazard ratios (HRs) adjusted by covariables. Results  A total of 1,300 OSA patients were included (Baveno A: 27.7%; B: 28%; C: 16.8%; and D: 27.5%). The follow-up was of 5.4 years. Compared to Baveno A, the fully-adjusted risk of cardiovascular mortality with Baveno B presented an HR of 1.38 (95% confidence interval [95%CI]: 0.14-13.5; p  = 0.78); with Baveno C, it was of 1.71 (95%CI: 0.18-16.2; p  = 0.63); and, with Baveno D, of 1.04 (95%CI: 0.12-9.2; p  = 0.98). We found no interactions involving Baveno group, sex and OSA severity. Discussion  Among OSA patients, the Baveno classification can describe different subgroups. However, its utility in identifying incident cardiovascular mortality is unclear. Long-term follow-up studies and the inclusion of demographic variables in the classification could improve its ability to detect a high-risk phenotype associated with cardiovascular mortality. Conclusion  The Baveno classification serves as a valuable method for categorizing varying groups of patients afflicted with OSA. Nevertheless, its precision in identifying occurrence of cardiovascular mortality is still unclear.

Translation of obstructive sleep apnea pathophysiology and phenotypes to personalized treatment: a narrative review

Obstructive Sleep Apnea (OSA) arises due to periodic blockage of the upper airway (UA) during sleep, as negative pressure generated during inspiration overcomes the force exerted by the UA dilator muscles to maintain patency. This imbalance is primarily seen in individuals with a narrowed UA, attributable to factors such as inherent craniofacial anatomy, neck fat accumulation, and rostral fluid shifts in the supine posture. Sleep-induced attenuation of UA dilating muscle responsiveness, respiratory instability, and high loop gain further exacerbate UA obstruction. The widespread comorbidity profile of OSA, encompassing cardiovascular, metabolic, and neuropsychiatric domains, suggests complex bidirectional relationships with conditions like heart failure, stroke, and metabolic syndrome. Recent advances have delineated distinct OSA phenotypes beyond mere obstruction frequency, showing links with specific symptomatic manifestations. It is vital to bridge the gap between measurable patient characteristics, phenotypes, and underlying pathophysiological traits to enhance our understanding of OSA and its interplay with related outcomes. This knowledge could stimulate the development of tailored therapies targeting specific phenotypic and pathophysiological endotypes. This review aims to elucidate the multifaceted pathophysiology of OSA, focusing on the relationships between UA anatomy, functional traits, clinical manifestations, and comorbidities. The ultimate objective is to pave the way for a more personalized treatment paradigm in OSA, offering alternatives to continuous positive airway pressure therapy for selected patients and thereby optimizing treatment efficacy and adherence. There is an urgent need for personalized treatment strategies in the ever-evolving field of sleep medicine, as we progress from a 'one-size-fits-all' to a 'tailored-therapy' approach.

Contrast Enhanced Ultrasonography of Kidney in Chronic Intermittent Hypoxia Rat Model

OBJECTIVES

The objective of our study was to assess the ability of contrast-enhanced ultrasound (CEUS) in evaluating renal microperfusion in an animal model.

METHODS

Twenty Sprague-Dawley rats were subdivided into two groups: the normal and chronic intermittent hypoxia (CIH) groups. In the CIH model, 10 Sprague-Dawley rats were exposed to CIH for 8 weeks to mimic obstructive sleep apnea (OSA). The CEUS parameters of the renal cortex and medulla were obtained and compared between groups. The pathological changes of the kidney tissues were examined by histological staining such as hematoxylin and eosin (H&E) and Masson's trichrome.

RESULTS

CIH caused morphological damage to kidneys. In the cortex, the peak intensity (PI) (P = .009) was significantly lower and time to peak (Ttop) (P = .019) was significantly prolonged in the CIH group compared with the controls. The area under ascending curve (WiAUC) in the medulla and cortex were both significantly lower in the CIH group than those in the control group (P both <.05). CEUS parameters (including PI and WiAUC of the cortex and WiAUC of the medulla) were negatively correlated with serum creatinine (P all <.05). In the medulla, the area under descending curve (WoAUC) was positively correlated with serum creatinine (P = .027), PI was negatively correlated with uric acid (P = .034).

CONCLUSION

CEUS parameters (including Ttop, PI, WoAUC, and WiAUC) reflect renal microvascular changes in CIH. CEUS could be a safe and accurate imaging method to assess renal microvascular damage in CIH rats.

Remote Monitoring of Positive Airway Pressure Data: Challenges, Pitfalls, and Strategies to Consider for Optimal Data Science Applications

Over recent years, positive airway pressure (PAP) remote monitoring has transformed the management of OSA and produced a large amount of data. Accumulated PAP data provide valuable and objective information regarding patient treatment adherence and efficiency. However, the majority of studies that have analyzed longitudinal PAP remote monitoring have summarized data trajectories in static and simplistic metrics for PAP adherence and the residual apnea-hypopnea index by the use of mean or median values. The aims of this article are to suggest directions for improving data cleaning and processing and to address major concerns for the following data science applications: (1) conditions for residual apnea-hypopnea index reliability, (2) lack of standardization of indicators provided by different PAP models, (3) missing values, and (4) consideration of treatment interruptions. To allow fair comparison among studies and to avoid biases in computation, PAP data processing and management should be conducted rigorously with these points in mind. PAP remote monitoring data contain a wealth of information that currently is underused in the field of sleep research. Improving the quality and standardizing data handling could facilitate data sharing among specialists worldwide and enable artificial intelligence strategies to be applied in the field of sleep apnea.

T cell receptor repertoire as a novel indicator for identification and immune surveillance of patients with severe obstructive sleep apnea

Background

Obstructive sleep apnea (OSA) is the most prevalent sleep disturbance that affects approximately 936 million people worldwide and leads to extensively increased incidence of cardiovascular disease, metabolic syndrome, neurological disorders, and traffic accidents. Severe OSA patients suffer a significantly higher risk of complications and worse comorbidity outcomes. Notwithstanding, with inadequate access to contact diagnosis based on polysomnography (PSG), numerous patients with severe sleep apnea have not been diagnosed, especially during the pandemic. Moreover, how the T cell immunity is impaired in OSA remains largely unknown.

Methods

We primarily investigated the T cell receptor (TCR) repertoires of 50 patients with severe OSA, 23 patients with mild-to-moderate OSA, 23 patients without OSA, and 157 healthy individuals, from their peripheral blood. Firstly, we compared the clinical characteristics, blood cell counts, the ratio of neutrophil-to-lymphocyte (NLR), platelet-to-lymphocyte (PLR), and CD4+/CD8+T cell count between groups. Then, we compared the diversity, clonotypes, unique VJ alleles in patients with different disease severity. Furthermore, by identifying a series of disease-associated amino acid sequences, we employed a repeated hold-out machine learning strategy to explore the optimal algorithm for calculating the TCR repertoire characteristic Index (OSA-TCI). We further confirmed its relation with clinical features by linear regression analysis. Moreover, in followup of severe OSA patients who accepted adherent non-invasive ventilation, we assessed the changes of TCR repertoires, OSA-TCI, ESS, NLR, PLR, and CD4+/CD8+T after therapy.

Results

We found an unexpected increase in diversity and clonotypes in the TCR repertoire of OSA patients. Furthermore, we successfully developed a novel indicator termed OSA-TCI to summarize the unique repertoire alteration, which provided 90% of sensitivity and 87% of specificity in distinguishing severe OSA. In rationalization, OSA-TCI was found correlated to AHI, BMI, hemoglobin, N1, N2 percentage of sleep, snoring, smoking and lowest oxygen saturation, but only independently related to AHI (R = 0.603) and smoking (R = 0.22). Finally, we observed OSA-TCI in the eight severe patients decreased significantly after home noninvasive ventilation for three months during follow-up, consistently in line with the TCR repertoire improvement. In contrast, NLR, PLR, and the ratio of CD4+/CD8+T cell count were found useless to diagnose and therapeutic surveillance of severe OSA.

Conclusions

Our study is the first to unveil the TCR repertoire alteration in OSA, indicates possible insidious autoimmune mechanisms underlying OSA, and suggests that TCR repertoires serve as a convenient peripheral blood biomarker for OSA assessment without long-time contact and facility/instrument occupation. It may shed light on future diagnostic, immunological, pathophysiological, and prognostic research on OSA.

Turning Over a New Leaf-Pharmacologic Therapy in Obstructive Sleep Apnea

Despite extensive research, there is currently no approved drug for obstructive sleep apnea (OSA) treatment. OSA is a heterogeneous condition that involves multiple dominating pathophysiological traits. Drug development in this field needs to address both pathophysiological mechanisms and associated comorbid conditions in order to meet requirements for long-term therapy in OSA. Several drug candidates have been proposed and ongoing phase II trials that target various forms of sleep-disordered breathing have been initiated. The field is moving toward tailored therapeutic approaches in patients with OSA.

Obstructive sleep apnea: transition from pathophysiology to an integrative disease model

Obstructive sleep apnea (OSA) is characterised by recurring episodes of upper airway obstruction during sleep and the fundamental abnormality reflects the inability of the upper airway dilating muscles to withstand the negative forces generated within the upper airway during inspiration. Factors that result in narrowing of the oropharynx such as abnormal craniofacial anatomy, soft tissue accumulation in the neck, and rostral fluid shift in the recumbent position increase the collapsing forces within the airway. The counteracting forces of upper airway dilating muscles, especially the genioglossus, are negatively influenced by sleep onset, inadequacy of the genioglossus responsiveness, ventilatory instability, especially post arousal, and loop gain. OSA is frequently associated with comorbidities that include metabolic, cardiovascular, renal, pulmonary, and neuropsychiatric, and there is growing evidence of bidirectional relationships between OSA and comorbidity, especially for heart failure, metabolic syndrome, and stroke. A detailed understanding of the complex pathophysiology of OSA encourages the development of therapies targeted at pathophysiological endotypes and facilitates a move towards precision medicine as a potential alternative to continuous positive airway pressure therapy in selected patients.

Defining obstructive sleep apnoea syndrome: a failure of semantic rules

Obstructive sleep apnoea syndrome (OSAS) is one of the most ubiquitous medical conditions in industrialised society. Since the recognition that symptoms of excessive daytime somnolence, problems with concentration, mood and cognitive impairment, as well as cardiometabolic abnormalities can arise as a consequence of obstructed breathing during sleep, it has been subject to variation in its definition. Over the past five decades, attempts have been made to standardise the definitions and scoring criteria used for apnoeas and hypopnoea, which are the hallmarks of obstructive sleep apnoea (OSA). However, applying these definitions in clinical and research practice has resulted in over- and under-estimation of the severity and prevalence of OSAS. Furthermore, the definitions may eventually become redundant in the context of rapid technological advances in breathing measurement and other signal acquisition. Increased efforts towards precision medicine have led to a focus on the pathophysiology of obstructed breathing during sleep. However, the same degree of effort has not been focused on how and why the latter does or does not result in diurnal symptoms, integral to the definition of OSAS. This review focuses on OSAS in adults and discusses some of the difficulties with current definitions and the possible reasons behind them.

The definition of obstructive sleep apnoea syndrome appears to be in constant flux dependent on the definitions attributed to its diagnostic componentshttps://bit.ly/3zXrWKg

Metabolomics and microbiome profiling as biomarkers in obstructive sleep apnoea: a comprehensive review

Introduction

Obstructive sleep apnoea (OSA) is a common sleep disorder with a high social and economic burden. Thus, early prediction and diagnosis of OSA are important. Changes in metabolism and the microbiome may serve as biomarkers for OSA. Herein, we review the literature on the metabolomic and microbiome changes associated with OSA, and identify the metabolites and microorganisms involved.

Methods

We searched the PUBMED and EMBASE electronic databases using the following terms: “obstructive sleep apnea”, “OSA”, “sleep disordered breathing”, “SDB”, “intermittent hypoxia”, “sleep fragmentation”, and either “metabolomics” or “microbiome”. In total, 273 papers were identified, of which 28 were included in our study.

Results

Changes in the levels of certain metabolites related to fatty acid, carbohydrate and amino acid metabolism were associated with the incidence of OSA. The diversity and abundance of microflora, particularly Firmicutes and Bacteroidetes, were altered in humans and rodents with OSA.

Conclusions

Certain changes in metabolism and the microbiota play an integral role in the pathophysiology of OSA and OSA-induced cardiovascular complications. Metabolomic and microbiome biomarkers shed light on the pathogenesis of OSA, and facilitate early diagnosis and treatment.

Unique alterations in metabolism and the microbiome play an integral role in the pathophysiology of OSA and OSA-induced cardiovascular complicationshttps://bit.ly/3mW2rD5

Comorbidity clusters in patients with moderate-to-severe OSA

PURPOSE

Obstructive sleep apnea (OSA) is a prevalent and multifaceted disease. To date, the presence and severity of objectively identified comorbidities and their association with specific OSA phenotypes, CPAP adherence, and survival remain to be elucidated. The aim of this study is to cluster patients with OSA based on 10 clinically important objectively identified comorbidities, and to characterize the comorbidity clusters in terms of clinical and polysomnographic characteristics, CPAP adherence, and survival.

STUDY DESIGN AND METHODS

Seven hundred ten consecutive patients starting CPAP for moderate-to-severe OSA were included. Comorbidities were based on generally accepted cutoffs identified in the peer-reviewed literature. Self-organizing maps were used to order patients based on presence and severity of their comorbidities and to generate clusters.

RESULTS

The majority of patients were men (80%). They were generally middle-aged (52 years) and obese (BMI: 31.5 kg/m²). Mean apnea-hypopnea index (AHI) was 41 ± 20 per h of sleep. More than 94% of the patients had one or more comorbidities with arterial hypertension, dyslipidemia, and obesity being the most prevalent. Nine comorbidity clusters were identified. The clinical relevance of these comorbidity clusters was highlighted by the difference in symptoms, PSG parameters, and cardiovascular risk. Also, differences in CPAP adherence, improvements in ESS, and long-term survival were present between the clusters.

CONCLUSION

Comorbidity prevalence in patients with OSA is high, and different comorbidity clusters, demonstrating differences in cardiovascular risk, CPAP adherence, and survival, can be identified. These results further substantiate the need for a comprehensive assessment of patients with OSA beyond the AHI.

Pitolisant versus placebo for excessive daytime sleepiness in narcolepsy and obstructive sleep apnea: A meta-analysis from randomized controlled trials

Excessive daytime sleepiness is considered as the prominent symptom in narcolepsy and Obstructive Sleep Apnea (OSA). Pitolisant is a novel selective histamine H3 receptor antagonist approved for improving excessive daytime sleepiness. The meta-analysis is conducted to assess the efficacy and safety of pitolisant versus placebo for excessive daytime sleepiness in narcolepsy and OSA. PubMed, Embase and Cochrane Library databases were searched from earliest date to November 2020 for randomized controlled trials (RCTs). The primary outcomes were mean changes in Epworth Sleepiness Scale (ESS), mean sleep latency, European quality-of-life questionnaire (EQ-5D), and risk ratio of treatment-emergent adverse events (TEAEs). We pooled 678 patients from four RCTs and found pitolisant significantly decreased ESS by mean difference (MD) of - 2.86 points (95% CI: -3.75 to -1.96), increased mean sleep latency by MD of 3.14 min (95% CI: 2.18-4.11), and increased EQ-5D by MD of 3.32 points (95% CI: 0.26-6.39) compared with placebo. The risk ratio of TEAE was 1.37 (95% CI: 1.08-1.74). Insomnia was the only TEAE significantly associated with pitolisant treatment. In conclusion, pitolisant showed great efficacy and controllable security versus placebo for excessive daytime sleepiness in narcolepsy and OSA. Compared with narcolepsy, patients with OSA were deemed to benefit more from pitolisant especially in terms of improving mobility and quality of life of patients without continuous positive airway pressure therapy.

CPAP Therapy Termination Rates by OSA Phenotype: A French Nationwide Database Analysis

The nationwide claims data lake for sleep apnoea (ALASKA)—real-life data for understanding and increasing obstructive sleep apnea (OSA) quality of care study—investigated long-term continuous positive airway pressure (CPAP) termination rates, focusing on the contribution of comorbidities. The French national health insurance reimbursement system data for new CPAP users aged ≥18 years were analyzed. Innovative algorithms were used to determine the presence of specific comorbidities (hypertension, diabetes and chronic obstructive pulmonary disease (COPD)). Therapy termination was defined as cessation of CPAP reimbursements. A total of 480,000 patients were included (mean age 59.3 ± 13.6 years, 65.4% male). An amount of 50.7, 24.4 and 4.3% of patients, respectively, had hypertension, diabetes and COPD. Overall CPAP termination rates after 1, 2 and 3 years were 23.1, 37.1 and 47.7%, respectively. On multivariable analysis, age categories, female sex (1.09 (1.08–1.10) and COPD (1.12 (1.10–1.13)) and diabetes (1.18 (1.16–1.19)) were significantly associated with higher CPAP termination risk; patients with hypertension were more likely to continue using CPAP (hazard ratio 0.96 (95% confidence interval 0.95–0.97)). Therapy termination rates were highest in younger or older patients with ≥1 comorbidity. Comorbidities have an important influence on long-term CPAP continuation in patients with OSA.

Long-term continuous positive airway pressure treatment ameliorates biological clock disruptions in obstructive sleep apnea

BACKGROUND

Obstructive Sleep Apnea (OSA) is a highly prevalent and underdiagnosed sleep disorder. Recent studies suggest that OSA might disrupt the biological clock, potentially causing or worsening OSA-associated comorbidities. However, the effect of OSA treatment on clock disruption is not fully understood.

METHODS

The impact of OSA and short- (four months) and long-term (two years) OSA treatment, with Continuous Positive Airway Pressure (CPAP), on the biological clock was investigated at four time points within 24 h, in OSA patients relative to controls subjects (no OSA) of the same sex and age group, in a case-control study. Plasma melatonin and cortisol, body temperature and the expression levels and rhythmicity of eleven clock genes in peripheral blood mononuclear cells (PBMCs) were assessed. Additional computational tools were used for a detailed data analysis.

FINDINGS

OSA impacts on clock outputs and on the expression of several clock genes in PBMCs. Neither short- nor long-term treatment fully reverted OSA-induced alterations in the expression of clock genes. However, long-term treatment was able to re-establish levels of plasma melatonin and cortisol and body temperature. Machine learning methods could discriminate controls from untreated OSA patients. Following long-term treatment, the distinction between controls and patients disappeared, suggesting a closer similarity of the phenotypes.

INTERPRETATION

OSA alters biological clock-related characteristics that differentially respond to short- and long-term CPAP treatment. Long-term CPAP was more efficient in counteracting OSA impact on the clock, but the obtained results suggest that it is not fully effective. A better understanding of the impact of OSA and OSA treatment on the clock may open new avenues to OSA diagnosis, monitoring and treatment.

Evaluation of a multicomponent grading system for obstructive sleep apnoea: the Baveno classification

New findings on pathophysiology, epidemiology, and outcome have raised concerns on the relevance of the apnoea-hypopnoea index (AHI) in the classification of obstructive sleep apnoea (OSA) severity. Recently, a multicomponent grading system decision integrating symptomatology and comorbidities (Baveno classification), was proposed to characterise OSA and to guide therapeutic decisions. We evaluated whether this system reflects the OSA population, whether it translates into differences in outcomes, and whether the addition of AHI improves the scheme. A total of 14 499 OSA patients from the European Sleep Apnoea Database cohort were analysed. The groups were homogeneously distributed and were found to clearly stratify the population with respect to baseline parameters. Differences in sleepiness and blood pressure between the groups were analysed in a subgroup of patients after 24-36 months of treatment. Group A (minor symptoms and comorbidities) did not demonstrate any effect of treatment on outcome. However, groups B (severe symptoms, minor comorbidities), C (minor symptoms, severe comorbidities) and D (severe symptoms and comorbidities) were associated with improvement in either or both parameters with treatment. The AHI is an essential prerequisite of the diagnosis; however, adding the AHI did not improve the classification. Rather, it was inferior with respect to guiding the treatment decision. Thus, the Baveno classification allows a better stratification of the OSA population and may provide a better guidance for therapeutic decisions in OSA.

Common risk factors and therapeutic targets in obstructive sleep apnea and osteoarthritis: An unexpectable link?

Osteoarthritis (OA) and Obstructive Sleep Apnea (OSA) are two highly prevalent chronic diseases for which effective therapies are urgently needed. Recent epidemiologic studies, although scarce, suggest that the concomitant occurrence of OA and OSA is associated with more severe manifestations of both diseases. Moreover, OA and OSA share risk factors, such as aging and metabolic disturbances, and co-morbidities, including cardiovascular and metabolic diseases, sleep deprivation and depression. Whether this coincidental occurrence is fortuitous or involves cause-effect relationships is unknown. This review aims at collating and integrating present knowledge on both diseases by providing a brief overview of their epidemiology and pathophysiology, analyzing current evidences relating OA and OSA and discussing potential common mechanisms by which they can aggravate each other. Such mechanisms constitute potential therapeutic targets whose pharmacological modulation may provide more efficient ways of reducing the consequences of OA and OSA and, thus, lessen the huge individual and social burden that they impose.

Clusters of sleep apnoea phenotypes: A large pan-European study from the European Sleep Apnoea Database (ESADA)

BACKGROUND AND OBJECTIVE

To personalize OSA management, several studies have attempted to better capture disease heterogeneity by clustering methods. The aim of this study was to conduct a cluster analysis of 23 000 OSA patients at diagnosis using the multinational ESADA.

METHODS

Data from 34 centres contributing to ESADA were used. An LCA was applied to identify OSA phenotypes in this European population representing broad geographical variations. Many variables, including symptoms, comorbidities and polysomnographic data, were included. Prescribed medications were classified according to the ATC classification and this information was used for comorbidity confirmation.

RESULTS

Eight clusters were identified. Four clusters were gender-based corresponding to 54% of patients, with two clusters consisting only of men and two clusters only of women. The remaining four clusters were mainly men with various combinations of age range, BMI, AHI and comorbidities. The preferred type of OSA treatment (PAP or mandibular advancement) varied between clusters.

CONCLUSION

Eight distinct clinical OSA phenotypes were identified in a large pan-European database highlighting the importance of gender-based phenotypes and the impact of these subtypes on treatment prescription. The impact of cluster on long-term treatment adherence and prognosis remains to be studied using the ESADA follow-up data set.

Pitolisant for Residual Excessive Daytime Sleepiness in OSA Patients Adhering to CPAP: A Randomized Trial

BACKGROUND

Excessive daytime sleepiness (EDS) in individuals with OSA syndrome persisting despite good adherence to CPAP is a disabling condition. Pitolisant is a selective histamine H3-receptor antagonist with wake-promoting effects.

RESEARCH QUESTION

Is pitolisant effective and safe for reducing daytime sleepiness in individuals with moderate to severe OSA adhering to CPAP treatment but experiencing residual EDS?

STUDY DESIGN AND METHODS

In a multicenter, double-blind, randomized (3:1), placebo-controlled, parallel-design trial, pitolisant was titrated individually at up to 20 mg/day and taken over 12 weeks. The primary end point was change in the Epworth Sleepiness Scale (ESS) score in the intention-to-treat population. Key secondary end points were maintenance of wakefulness assessed by the Oxford Sleep Resistance Test, Clinical Global Impressions scale of severity, the patient's global opinion, EuroQoL quality-of-life questionnaire score, Pichot fatigue questionnaire score, and safety.

RESULTS

Two hundred forty-four OSA participants (82.8% men; mean age, 53.1 years; mean Apnea Hypopnea Index with CPAP, 4.2/h; baseline ESS score, 14.7) were randomized to pitolisant (n = 183) or placebo (n = 61). ESS significantly decreased with pitolisant compared with placebo (-2.6; 95% CI, -3.9 to -1.4; P < .001), and the rate of responders to therapy (ESS ≤ 10 or change in ESS ≥ 3) was significantly higher with pitolisant (71.0% vs 54.1%; P = .013). Adverse event occurrence (mainly headache and insomnia) was higher in the pitolisant group compared with the placebo group (47.0% and 32.8%, respectively; P = .03). No cardiovascular or other significant safety concerns were reported.

INTERPRETATION

Pitolisant used as adjunct to CPAP therapy for OSA with residual sleepiness despite good CPAP adherence significantly reduced subjective and objective sleepiness and improved participant-reported outcomes and physician-reported disease severity.

TRIAL REGISTRY

ClinicalTrials.gov; No.: NCT01071876; URL: www.clinicaltrials.gov; EudraCT N°: 2009-017248-14; URL: eudract.ema.europa.eu.

Usefulness of Cathepsin S to Predict Risk for Obstructive Sleep Apnea among Patients with Type 2 Diabetes

Background

Obstructive sleep apnea (OSA) was highly prevalent in patients with type 2 diabetes (T2D). Cathepsin S (CTSS), a cysteine protease, is involved in the inflammatory activity in T2D and hypoxia conditions. The aim of the study was to evaluate whether CTSS could be involved in the inflammatory reaction of OSA in patients with T2D.

Methods

We included 158 participants in this study matched for age, gender, and body mass index in 4 groups (control, non-OSA&T2D, OSA&non-T2D, and OSA&T2D). After overnight polysomnography, we collected the clinical data including anthropometrical characteristics, blood pressure, and fasting blood samples in the morning. Plasma CTSS concentration was evaluated using the human Magnetic Luminex Assay.

Results

Compared with the control group, both the non-OSA&T2D group and the OSA&non-T2D group showed higher CTSS levels. Plasma CTSS expression was significantly increased in subjects with OSA&T2D compared to subjects with non-OSA&T2D. The OSA&T2D group had higher CTSS levels than the OSA&non-T2D group, but there were no statistically significant differences. Plasma CTSS levels showed significant correlation with the apnea-hypopnea index (AHI) (r = 0.559, P < 0.001) and plasma fasting blood glucose (r = 0.427, P < 0.001). After adjusting confounding factors, plasma CTSS levels were independently associated with the AHI (Beta: 0.386, 95% confidence intervals (CI): 21.988 to 57.781; P < 0.001). Furthermore, we confirmed the higher pinpoint accuracy of plasma CTSS in the diagnosis of OSA (area under the curve: 0.868).

Conclusions

Plasma CTSS expression was significantly elevated in the OSA&T2D group and was independently associated with the AHI; it could be a biomarker with a positive diagnostic value on diagnosing OSA among patients with T2D.

Pitolisant for Daytime Sleepiness in Patients with Obstructive Sleep Apnea Who Refuse Continuous Positive Airway Pressure Treatment. A Randomized Trial

Rationale: Excessive daytime sleepiness is a common disabling symptom in obstructive sleep apnea syndrome.

Objectives: To evaluate the efficacy and safety of pitolisant, a selective histamine H3 receptor antagonist with wake-promoting effects, for the treatment of daytime sleepiness in patients with moderate to severe obstructive sleep apnea refusing continuous positive airway pressure treatment.

Methods: In an international, multicenter, double-blind, randomized (3:1), placebo-controlled, parallel-design trial, pitolisant was individually titrated at up to 20 mg/d over 12 weeks. The primary endpoint was the change in the Epworth Sleepiness Scale score. Key secondary endpoints were maintenance of wakefulness assessed on the basis of the Oxford Sleep Resistance test, safety, Clinical Global Impression of severity, patient’s global opinion, EuroQol quality-of-life questionnaire, and Pichot fatigue questionnaire.

Measurements and Main Results: A total of 268 patients with obstructive sleep apnea (75% male; mean age, 52 yr; apnea–hypopnea index, 49/h; baseline sleepiness score, 15.7) were randomized (200 to pitolisant and 68 to placebo) and analyzed on an intention-to-treat basis. The Epworth Sleepiness Scale score was reduced more with pitolisant than with placebo (−2.8; 95% confidence interval, −4.0 to −1.5; P < 0.001). Wake maintenance tests were not improved. The Pichot fatigue score was reduced with pitolisant. The overall impact of pitolisant was confirmed by both physicians’ and patients’ questionnaires. Adverse event incidence, mainly headache, insomnia, nausea, and vertigo, was similar in the pitolisant and placebo groups (29.5% and 25.4%, respectively), with no cardiovascular or other significant safety concerns.

Conclusions: Pitolisant significantly reduced self-reported daytime sleepiness and fatigue and improved patient-reported outcomes and physician disease severity assessment in sleepy patients with obstructive sleep apnea refusing or nonadherent to continuous positive airway pressure.

Clinical trial registered with www.clinicaltrials.gov (NCT01072968) and EU Clinical Trials Register (EudraCT 2009-017251-94).

The association between circulating APRIL levels and severity of obstructive sleep apnea in Chinese adults

BACKGROUND

Obstructive sleep apnea (OSA) is the most common type of sleep breathing disorder and is characterized by chronic intermittent hypoxia, which could cause inflammation and nuclear factor kappa B (NF-KB)-dependent inflammatory pathways activation. Circulating APRIL (a proliferation-inducing ligand) play an important role in promoting inflammation and NF-KB-dependent inflammatory pathways activation. We explored the role of APRIL as a potential mechanism of inflammation in OSA patients.

METHODS

After detailed sleep evaluated, venous blood and demographic data were collected from 155 subjects with varying severity of OSA and 52 control subjects. Plasma levels of APRIL were measured by human Magnetic Luminex assay.

RESULTS

Plasma APRIL levels were significantly higher in OSA subjects compared with control subjects. Categorization of the OSA subjects into mild, moderate, and severe OSA subgroups found that plasma levels of APRIL increased with the severity of OSA. After adjusting confounding factors, found that increased plasma APRIL levels were conferred a higher odds ratio of OSA. Moreover, plasma APRIL levels were positively associated with the apnea-hypopnea index, which represents the severity of OSA. Furthermore, plasma APRIL showed higher discriminatory accuracy in predicting the presence of OSA.

CONCLUSIONS

Plasma APRIL levels were significantly associated with the occurrence of OSA and its severity. APRIL could be a plasma biomarker with a positive diagnostic value for inflammation and NF-KB-dependent inflammatory pathways activation in subjects with OSA.

TRIAL REGISTRATION

The project was approved by the Chinese Clinical Trial Registry (No. ChiCTRROC-17011027).

EAN/ERS/ESO/ESRS statement on the impact of sleep disorders on risk and outcome of stroke

Sleep disorders are highly prevalent in the general population and may be linked in a bidirectional fashion to stroke, which is one of the leading causes of morbidity and mortality.Four major scientific societies established a task force of experts in neurology, stroke, respiratory medicine, sleep medicine and methodology, to critically evaluate the evidence regarding potential links and the impact of therapy. 13 research questions were evaluated in a systematic literature search using a stepwise hierarchical approach: first, systematic reviews and meta-analyses; second, primary studies post-dating the systematic reviews/meta-analyses. A total of 445 studies were evaluated and 88 included. Statements were generated regarding current evidence and clinical practice.Severe obstructive sleep apnoea (OSA) doubles the risk for incident stroke, especially in young to middle-aged patients. Continuous positive airway pressure (CPAP) may reduce stroke risk, especially in treatment-compliant patients. The prevalence of OSA is high in stroke patients and can be assessed by polygraphy. Severe OSA is a risk factor for recurrence of stroke and may be associated with stroke mortality, while CPAP may improve stroke outcome. It is not clear if insomnia increases stroke risk, while pharmacotherapy of insomnia may increase it. Periodic limb movements in sleep (PLMS), but not restless limb syndrome (RLS), may be associated with an increased risk of stroke. Preliminary data suggest a high frequency of post-stroke insomnia and RLS and their association with a less favourable stroke outcome, while treatment data are scarce.Overall, the evidence base is best for OSA relationship with stroke and supports active diagnosis and therapy. Research gaps remain especially regarding insomnia and RLS/PLMS relationships with stroke.

Remotely controlled mandibular positioning of oral appliance therapy during polysomnography and drug-induced sleep endoscopy compared with conventional subjective titration in patients with obstructive sleep apnea: protocol for a randomized crossover trial

BACKGROUND

The amount of mandibular protrusion is a key factor in optimizing the efficacy of mandibular advancement device (MAD) therapy in an individual patient diagnosed with obstructive sleep apnea. This process is called titration and is generally based on resolution of subjective symptoms like snoring and/or daytime sleepiness as a function of protrusion. An objective approach uses a remotely controlled mandibular positioner (RCMP) during a full-night polysomnography (PSG), in analogy with continuous positive airway pressure (CPAP) titration. More recently, the feasibility of RCMP use during drug-induced sleep endoscopy (DISE) titration was reported.

METHODS

This randomized crossover trial will compare DISE-assisted titration to PSG-guided titration, as well as with the conventional subjective titration method. The primary outcome is the actual mandibular protrusive position found to be the most optimal for each tested titration procedure. Furthermore, the therapeutic efficacy will be compared among the different titration modalities using level 1 sleep studies.

DISCUSSION

Currently, the optimal titration of MAD therapy is most often based on 'trial and error'. The conventional method relies on subjective improvement in symptoms, although this may not provide the most accurate indicator for efficient titration. Therefore, relying on objective criteria in the titration process should be advantageous. In analogy with CPAP, titration of the most optimal mandibular protrusion could be performed using RCMP during an overnight titration PSG. Recently, it was shown that titration under direct visualization of upper airway patency and collapsibility is feasible using the RCMP during DISE. However, no clinical results for such a procedure are as yet available. This study is the first to compare the most optimal mandibular protrusive position according to three titration procedures, as well as to compare the therapeutic efficacy of these titration methods.

TRIAL REGISTRATION

ClinicalTrials.gov, NCT03716648 . Registered on 23 October 2018.

Management of insomnia in sleep disordered breathing

Both obstructive sleep apnoea (OSA) and chronic insomnia disorder are highly prevalent in the general population. Whilst both disorders may occur together by mere coincidence, it appears that they share clinical features and that they may aggravate each other as a result of reciprocally adverse pathogenetic mechanisms. Comorbidity between chronic insomnia disorder and OSA is a clinically relevant condition that may confront practitioners with serious diagnostic and therapeutic challenges. Current data, while still scarce, advocate an integrated and multidisciplinary approach that seems superior over the isolated treatment of each sleep disorder alone.

Obstructive sleep apnoea in acute coronary syndrome

Obstructive sleep apnoea (OSA) syndrome affects about 13% of the male and 7-9% of the female population. Hypoxia, oxidative stress and systemic inflammation link OSA and cardiovascular and metabolic consequences, including coronary artery disease. Current research has identified several clinical phenotypes, and the combination of breathing disturbances during sleep, systemic effects and end-organ damage might help to develop personalised therapeutic approaches. It is unclear whether OSA is a risk factor for acute coronary syndrome (ACS) and might affect its outcome. On the one hand, OSA in patients with ACS may worsen prognosis; on the other hand, OSA-related hypoxaemia could favour the development of coronary collaterals, thereby exerting a protective effect. It is unknown whether positive airway pressure treatment may influence adverse events and consequences of ACS. In non-sleepy patients with OSA and stable coronary artery disease, randomised controlled trials failed to show that continuous positive airway pressure (CPAP) treatment protected against cardiovascular events. Conversely, uncontrolled studies suggested positive effects of CPAP treatment in such patients. Fewer data are available in subjects with ACS and OSA, and results of randomised controlled studies on the effects of CPAP are expected shortly. Meanwhile, the search for reliable markers of risk continues. Recent studies suggest that daytime sleepiness may indicate a more severe OSA phenotype with regard to cardiovascular risk. Finally, some studies suggest sex-related differences. The picture is still incomplete, and the potential role of OSA in patients with ACS awaits confirmation, as well as clear definition of subgroups with different degrees of risk.

Update on obstructive sleep apnea for neuro-ophthalmology

PURPOSE OF REVIEW

Obstructive sleep apnea (OSA) is increasing in prevalence. The intermittent hypoxia of OSA has wide-ranging effects on a patient's general health outcomes. However, gold-standard investigations and treatment are expensive and a significant burden on patients. Therefore, OSA research remains focused on improving the means of diagnosing and treating OSA, in high-risk-associated conditions. This review is to provide an update on the advances in the field of OSA.

RECENT FINDINGS

There has been recent debate about the best practice for diagnosis and treatment of OSA. Further work has been done on conditions associated with OSA including hypertension, atherosclerosis, various types of dementia and intracranial aneurysms. Inflammatory and vascular risk factors associated with OSA increase stroke risk and alter outcomes for recovery. OSA should definitely be considered in patients presenting with nonarteritic anterior ischemic optic neuropathy, and perhaps those with intracranial hypertension.

SUMMARY

Newer home-based sleep-apnea testing can be implemented via physician clinics, with oversight by a certified sleep physician. Although continuous positive airway pressure (CPAP) is the gold-standard, management should include diet and exercise. It is important to test for, and treat OSA in patients with a range of neurological diseases. However, further studies into the long-term impact of CPAP on health outcomes are still needed.

Particularities of Older Patients with Obstructive Sleep Apnea and Heart Failure with Mid-Range Ejection Fraction

Background and objectives: Obstructive sleep apnea syndrome (OSAS) and heart failure (HF) are increasing in prevalence with a greater impact on the health system. The aim of this study was to assess the particularities of patients with OSAS and HF, focusing on the new class of HF with mid-range ejection fraction (HFmrEF, EF = 40%-49%), and comparing it with reduced EF (HFrEF, EF < 40%) and preserved EF (HFpEF, EF ≥ 50%). Materials and Methods: A total of 143 patients with OSAS and HF were evaluated in three sleep labs of "Victor Babes" Hospital and Cardiovascular Institute, Timisoara, Western Romania. We collected socio-demographic data, anthropometric sleep-related measurements, symptoms through sleep questionnaires and comorbidity-related data. We performed blood tests, cardio-respiratory polygraphy and echocardiographic measurements. Patients were divided into three groups depending on ejection fraction. Results: Patients with HFmrEF were older (p = 0.0358), with higher values of the highest systolic blood pressure (mmHg) (p = 0.0016), higher serum creatinine (p = 0.0013), a lower glomerular filtration rate (p = 0.0003), higher glycemic levels (p = 0.008) and a larger left atrial diameter (p = 0.0002). Regarding comorbidities, data were presented as percentage, HFrEF vs. HFmrEF vs. HFpEF. Higher prevalence of diabetes mellitus (52.9 vs. 72.7 vs. 40.2, p = 0.006), chronic kidney disease (17.6 vs. 57.6 vs. 21.5, p < 0.001), tricuspid insufficiency (76.5 vs. 84.8 vs.59.1, p = 0.018) and aortic insufficiency (35.3 vs.42.4 vs. 20.4, p = 0.038) were observed in patients with HFmrEF, whereas chronic obstructive pulmonary disease(COPD) (52.9 vs. 24.2 vs.18.3, p = 0.009), coronary artery disease(CAD) (82.4 vs. 6.7 vs. 49.5, p = 0.026), myocardial infarction (35.3 vs. 24.2 vs. 5.4, p < 0.001) and impaired parietal heart kinetics (70.6 vs. 68.8 vs. 15.2, p < 0.001) were more prevalent in patients with HFrEF. Conclusions: Patients with OSAS and HF with mid-range EF may represent a new group with increased risk of developing life-long chronic kidney disease, diabetes mellitus, tricuspid and aortic insufficiency. COPD, myocardial infarction, impaired parietal kinetics and CAD are most prevalent comorbidities in HFrEF patients but they are closer in prevalence to HFmrEF than HFpEF.

Partial failure of CPAP treatment for sleep apnoea: Analysis of the French national sleep database

BACKGROUND AND OBJECTIVE

Continuous positive airway pressure (CPAP) is the first-line therapy for obstructive sleep apnoea (OSA). Residual apnoea and/or hypopnoea events, that is an apnoea-hypopnoea index (AHI) > 5, during CPAP contribute to treatment drop-out. The clinical scenarios triggering residual events during CPAP use are poorly described. Underlying co-morbidities, especially cardiovascular diseases, lifestyle factors, OSA characteristics at diagnosis and type of mask have been suggested as potential contributors.

METHODS

Patients from the prospective French sleep apnoea registry diagnosed with OSA (AHI ≥ 15 events/h) treated with CPAP were included. Logistic regression analysis identified factors associated with a risk of residual AHI > 5 events/h on CPAP.

RESULTS

The 12 285 OSA patients were predominantly men (n = 8715, 70.9%), middle-aged (58.2 (49.8; 66.1) years) and obese (median body mass index: 31.3 (27.7; 35.6) kg/m² ). Most had an AHI ≤ 5 events/h (n = 9573, 77.9%) versus 22.1% with AHI > 5/h. The latter were less CPAP adherent (5.75 (4.01; 7.00) vs 6.00 (4.53; 7.00) h/night). In multivariable analysis, factors associated with residual AHI >5/h were male sex, age, sedentary lifestyle, OSA severity, cardiovascular co-morbidities (heart failure and arrhythmia) and type of interface (orofacial mask versus nasal mask: OR = 2.15 (95%CI: 1.95; 2.37)). A subgroup analysis found that patients using pressures above 10 cm H₂ O were 1.43 (95% CI: 1.3; 1.57) times more likely to have residual AHI > 5/h.

CONCLUSION

Knowing about risk factors for residual apnoeic-hypopnoeic events may assist in the timely provision of personalized care including the type of PAP therapy, attention to co-morbidities and choice of interface.

Adipose tissue as a key player in obstructive sleep apnoea

Obstructive sleep apnoea (OSA) is a major health concern worldwide and adversely affects multiple organs and systems. OSA is associated with obesity in >60% of cases and is independently linked with the development of numerous comorbidities including hypertension, arrhythmia, stroke, coronary heart disease and metabolic dysfunction. The complex interaction between these conditions has a significant impact on patient care and mortality. The pathophysiology of cardiometabolic complications in OSA is still incompletely understood; however, the particular form of intermittent hypoxia (IH) observed in OSA, with repetitive short cycles of desaturation and re-oxygenation, probably plays a pivotal role. There is fast growing evidence that IH mediates some of its detrimental effects through adipose tissue inflammation and dysfunction. This article aims to summarise the effects of IH on adipose tissue in experimental models in a comprehensive way. Data from well-designed controlled trials are also reported with the final goal of proposing new avenues for improving phenotyping and personalised care in OSA.

Fast growing evidence strongly suggests that cardiovascular and metabolic alterations induced by intermittent hypoxia in OSA are mediated through adipose tissue inflammation and dysfunction.bit.ly/2W929Pe

Does the Patient-Reported Apnea Questionnaire (PRAQ) increase patient-centredness in the daily practice of sleep centres? a mixed-methods study

OBJECTIVES

The objective of this exploratory study was to see how the Patient-Reported Apnea Questionnaire (PRAQ) may impact the daily clinical practice of sleep centres, and why it may or may not work as expected. The hypotheses were tested that this patient-reported outcome measure makes patients more aware of which of their health complaints may be related to obstructive sleep apnoea (OSA), and that it improves patient-centredness of care by shifting the focus of care away from (only) medical problems towards the individual burden of disease and quality of life.

DESIGN

Mixed methods. The quantitative study (surveys, patient records) was a before-and-after study.

SETTING

Three sleep centres in The Netherlands (secondary care).

PARTICIPANTS

27 patients and 14 healthcare professionals were interviewed. 487 patients completed surveys pre-implementation, and 377 patients completed surveys post-implementation of the PRAQ. For the health records, 125 patients were included in the pre-implementation group, and 124 other patients in the post-implementation group.

INTERVENTIONS

The PRAQ was used in clinical practice for six successive months.

OUTCOME MEASURES

Scores on individual survey items, number of patients receiving non-medical treatment, adjustment of treatment at first follow-up, compliance with treatment.

RESULTS

Patients were generally positive about the usefulness of the PRAQ before and during the consultation, as they felt more informed. Healthcare providers did not consider the PRAQ very useful, and they reported minor impact on their consultations. The surveys and health record study did not show an impact of the PRAQ on clinical practice.

CONCLUSIONS

Implementing the PRAQ may be beneficial to patients, but this study does not show much impact with regard to patient-centredness of care. New Dutch guidelines for OSA care may lead to a greater emphasis on quality of life and value of care for patients, making its integration in clinical care potentially more useful.

Current opinions for the management of asthma associated with ear, nose and throat comorbidities

Ear, nose and throat (ENT) comorbidities are common in patients with asthma and are frequently associated with poorer asthma outcomes. All these comorbidities are "treatable traits" in asthma. Identification and management of these disorders may spare medication usage and contribute to improved asthma control and quality of life, and a decrease in exacerbation rates.This review summarises recent data about the prevalence, clinical impact and treatment effects of ENT comorbidities in asthma including allergic rhinitis, chronic rhinosinusitis with and without nasal polyposis, aspirin-exacerbated respiratory disease, obstructive sleep apnoea and vocal cord dysfunction.Many of these comorbidities are possible to be managed by the pulmonologist, but the collaboration with the ENT specialist is essential for patients with chronic rhinosinusitis or vocal cord dysfunction. Further rigorous research is needed to study the efficacy of comorbidity treatment to improve asthma outcomes, in particular with the development of biotherapies in severe asthma that can also be beneficial in some ENT diseases.

SAS score: Targeting high-specificity for efficient population-wide monitoring of obstructive sleep apnea

Proposal

This paper investigates a novel screening tool for Obstructive Sleep Apnea Syndrome (OSAS), which aims at efficient population-wide monitoring. To this end, we introduce SAS_score which provides better OSAS prediction specificity while maintaining a high sensitivity.

Methods

We process a cohort of 2595 patients from 4 sleep laboratories in Western Romania, by recording over 100 sleep, breathing, and anthropometric measurements per patient; using this data, we compare our SAS_score with state of the art scores STOP-Bang and NoSAS through area under curve (AUC), sensitivity, specificity, negative predictive value (NPV), and positive predictive value (PPV). We also evaluate the performance of SAS_score by considering different Apnea–Hypopnea Index (AHI) diagnosis cut-off points and show that custom refinements are possible by changing the score’s threshold.

Results

SAS_score takes decimal values within the interval (2, 7) and varies linearly with AHI; it is based on standardized measures for BMI, neck circumference, systolic blood pressure and Epworth score. By applying the STOP-Bang and NoSAS questionnaires, as well as the SAS_score on the patient cohort, we respectively obtain the AUC values of 0.69 (95% CI 0.66-0.73, p < 0.001), 0.66 (95% CI 0.63-0.68, p < 0.001), and 0.73 (95% CI 0.71-0.75, p < 0.001), with sensitivities values of 0.968, 0.901, 0.829, and specificity values of 0.149, 0.294, 0.359, respectively. Additionally, we cross-validate our score with a second independent cohort of 231 patients confirming the high specificity and good sensitivity of our score. When raising SAS_score’s diagnosis cut-off point from 3 to 3.7, both sensitivity and specificity become roughly 0.6.

Conclusions

In comparison with the existing scores, SAS_score is a more appropriate screening tool for monitoring large populations, due to its improved specificity. Our score can be tailored to increase either sensitivity or specificity, while balancing the AUC value.

Minimum important difference of the Epworth Sleepiness Scale in obstructive sleep apnoea: estimation from three randomised controlled trials

BACKGROUND

The Epworth Sleepiness Scale (ESS) is a widely used tool for assessing sleepiness in patients with obstructive sleep apnoea (OSA). We aimed to estimate the minimal important difference (MID) in patients with OSA.

METHODS

We used individual data from three randomised controlled trials (RCTs) in patients with OSA where the preintervention to postintervention change in ESS was used as a primary outcome. We used anchor-based linear regression and responder analysis approaches to estimate the MID. For anchors, we used the change in domains of the Functional Outcomes of Sleep Questionnaire and 36-Item Short Form Health Survey. We also used the distribution-based approaches Cohen's effect size, SE of measurement and empirical rule effect size to support the anchor-based estimates. The final MID was determined by triangulating all estimates to a single MID.

FINDINGS

A total of 639 patients with OSA were included in our analyses across the three RCTs with a median (IQR) baseline ESS score of 10 (6-13). The median (IQR) ESS change score overall was -2 (-5 to 1). The anchor-based estimates of the MID were between -1.74 and -4.21 points and estimates from the responder analysis were between -1 and -3 points. Distribution-based estimates were smaller, ranging from -1.46 to -2.36.

INTERPRETATION

We propose an MID for the ESS of 2 points in patients with OSA with a disease severity from mild to severe. This estimate provides the means to plan trials and interpret the clinical relevance of changes in ESS.

TRIAL REGISTRATION NUMBER

Provent, NCT01332175; autoCPAP trial, NCT00280800; MOSAIC,ISRCTN (3416388).