CLINICAL REVIEW ARTICLE: Epidemiology of sleep-related obstructive breathing

The firstly visited department affects the acceptance of CPAP in patients with obstructive sleep apnea: a cohort study

BACKGROUND

Continuous positive airway pressure (CPAP) therapy is the first-line treatment for obstructive sleep apnea (OSA). However, the low acceptance rate of CPAP remains a challenging clinical issue. This study aimed to determine the factors that influence the acceptance rate of CPAP.

METHODS

This retrospective cohort study was conducted at the sleep center of Shuang-Ho Hospital. Initially, 1186 OSA patients who received CPAP therapy between December 2013 and December 2017 were selected, and finally, 1016 patients were analyzed. All patients with OSA received CPAP therapy for at least 1 week, and their acceptance to treatment was subsequently recorded. Outcome measures included patients' demographic and clinical characteristics (sex, age, BMI, comorbidities, history of smoking, and the medical specialist who prescribed CPAP treatment), polysomnography (PSG) results, and OSA surgical records.

RESULTS

Patients with a lower CPAP acceptance rate were referred from otolaryngologists (acceptance rate of otolaryngology vs. others: 49.6% vs. 56.6%, p = .015), in addition to having a lower apnea-hypopnea index (AHI) (acceptance vs. non-acceptance: 55.83 vs. 40.79, p = .003), rapid eye movement AHI (REM-AHI) (acceptance vs. non-acceptance: 51.21 vs. 44.92, p = .014), and arousal index (acceptance vs. non-acceptance: 36.80 vs. 28.75, p = .011). The multiple logistic regression model showed that patients referred from otolaryngology had a lower CPAP acceptance rate (odds ratio 0.707, p = .0216) even after adjusting for age, sex, BMI, AHI, REM-AHI, arousal index, comorbidities, and smoking status.

CONCLUSIONS

Before their initial consultation, patients may already have their preferred treatment of choice, which is strongly linked to the type of medical specialists they visit, and consequently, affects their rate of acceptance to CPAP therapy. Therefore, physicians should provide personalized care to patients by exploring and abiding by their preferred treatment choices.

Inspiratory muscle training as adjuvant therapy in obstructive sleep apnea: a randomized controlled trial

The aim of this randomized controlled trial was to analyze the effects of an inspiratory muscle training (IMT) program on apnea and hypopnea index (AHI), inspiratory muscle strength, sleep quality, and daytime sleepiness in individuals with obstructive sleep apnea (OSA), whether or not they used continuous positive airway pressure (CPAP (+/−) therapy. The intervention group underwent IMT with a progressive resistive load of 40-70% of the maximum inspiratory pressure (PImax) for 30 breaths once a day for 12 weeks. The control group was submitted to a similar protocol, but with at a minimum load of 10 cmH₂O. Changes in the AHI were the primary outcome. PImax was measured with a digital vacuometer, daytime somnolence was measured by the Epworth sleepiness scale (ESS), and the quality of sleep by the Pittsburgh Sleep Quality Index (PSQI). CPAP use was treated as a confounder and controlled by stratification resulting in 4 subgroups: IMT−/CPAP−, IMT−/CPAP+, IMT+/CPAP−, and IMT+/CPAP+. Sixty-five individuals were included in the final analysis. Significant variations were found in the 4 parameters measured throughout the study after the intervention in both CPAP− and CPAP+ participants: PImax was increased and AHI was reduced, whereas improvements were seen in both ESS and PSQI. The twelve-week IMT program increased inspiratory muscle strength, substantially reduced AHI, and had a positive impact on sleep quality and daytime sleepiness, whether or not participants were using CPAP. Our findings reinforce the role of an IMT program as an adjunct resource in OSA treatment.

The invisible costs of obstructive sleep apnea (OSA): Systematic review and cost-of-illness analysis

BACKGROUND

Obstructive sleep apnea (OSA) is a risk factor for several diseases and is correlated with other non-medical consequences that increase the disease's clinical and economic burden. However, OSA's impact is highly underestimated, also due to substantial diagnosis gaps.

OBJECTIVE

This study aims at assessing the economic burden of OSA in the adult population in Italy by performing a cost-of-illness analysis with a societal perspective. In particular, we aimed at estimating the magnitude of the burden caused by conditions for which OSA is a proven risk factor.

METHODS

A systematic literature review on systematic reviews and meta-analyses, integrated by expert opinion, was performed to identify all clinical and non-clinical conditions significantly influenced by OSA. Using the Population Attributable Fraction methodology, a portion of their prevalence and costs was attributed to OSA. The total economic burden of OSA for the society was estimated by summing the costs of each condition influenced by the disease, the costs due to OSA's diagnosis and treatment and the economic value of quality of life lost due to OSA's undertreatment.

RESULTS

Twenty-six clinical (e.g., diabetes) and non-clinical (e.g., car accidents) conditions were found to be significantly influenced by OSA, contributing to an economic burden ranging from €10.7 to €32.0 billion/year in Italy. The cost of impaired quality of life due to OSA undertreatment is between €2.8 and €9.0 billion/year. These costs are substantially higher than those currently borne to diagnose and treat OSA (€234 million/year).

CONCLUSIONS

This study demonstrates that the economic burden due to OSA is substantial, also due to low diagnosis and treatment rates. Providing reliable estimates of the economic impact of OSA at a societal level may increase awareness of the disease burden and help to guide evidence-based policies and prioritisation for healthcare, ultimately ensuring appropriate diagnostic and therapeutic pathways for patients.

Smoking and Obstructive Sleep Apnea: Is There An Association between These Cardiometabolic Risk Factors?-Gender Analysis

Background and Objectives: Studies have tried to establish a relationship between Obstructive Sleep Apnea syndrome (OSA) and smoking but data still remain controversial. We aimed: 1. To evaluate the relationship between smoking and OSA; 2. To explore potential differences according to gender, and 3. To analyze the prevalence of cardiovascular disease (CVD) co-morbidities according to gender and smoking status. Materials and Methods: This retrospective study included 3791 (70.6% males) adult patients who visited a Sleep Clinic. All participants underwent nocturnal polysomnography. Daytime somnolence and insomnia were assessed by using the Epworth Sleepiness Scale (ESS) and the Athens Insomnia Scale (AIS). Ever-smokers completed the Fagerstrom Test for Nicotine Dependence (FTND). Results: OSA was confirmed in 72.1% of participants with 62.2% suffering from moderate-to-severe disease. The number of cigarettes/day, Pack/Years, and FTND were significantly higher in patients with more severe OSA. The prevalence of current smokers was higher in those without OSA or with mild disease, whereas the prevalence of former smokers was higher in moderate and severe OSA. In univariate analysis, current smokers were found to be 1.2 times more likely to have OSA compared with never and former smokers combined and former smokers 1.49 times more likely compared with never smokers. In the multiple regression analysis, after adjusting for BMI, gender, age and number of alcoholic drinks per week, smoking was not found to be significantly associated with OSA. In gender stratified multivariate analyses, no significant associations were observed. CVD co-morbidities were more frequent in more severe OSA. Hypertension, coronary disease and diabetes were more prevalent in former smokers with AHI ≥ 15, compared with current smokers, especially in men. Conclusions: Even if an independent effect of smoking on OSA was not found, the number of cigarettes/day, Pack/Years, and FTND were higher in patients with more severe OSA with more prevalent CVD co-morbidities.

Chronic Heart Failure in Patients with Arterial Hypertension Associated with Obstructive Sleep Apnea Syndrome: Possible Options to Pathogenetic Therapy

Aim. To study approaches to the treatment of chronic heart failure (CHF) with reduced and mid-range left ventricular ejection fraction (LVEF) in patients with arterial hypertension (AH) against the background of obstructive sleep apnea (OSA).

Material and methods. The study included 136 patients with CHF and AH. Inclusion criteria for the study: 1) moderate and severe OSA (with an apnea/hypopnea index of more than 15 per hour); 2) II-IV functional class of CHF according to NYHA; 3) the level of brain natriuretic peptide precursor (NT-proBNP) ≥125 pg/ml; 3) LVEF <50%; 4) the duration of hypertension is at least 2 years. Patients received drug therapy, including beta-blockers, mineralocorticoid receptor antagonists, diuretics, ACE inhibitors or angiotensin receptor inhibitors or valsartan/sacubitrile. After 12 months of followup, the patients were divided into 2 groups depending on the medication being administered. Group 1 included patients (n = 50) receiving therapy with valsartan/sacubitril, group 2 included patients (n = 86) receiving therapy without this drug. Effective CPAP-therapy also was registered in each group.

Results. In patients with CHF who received valsartan/sacubitril, disease progression was recorded in 28% of cases, while in patients who did not receive therapy with this drug, an unfavorable course of CHF was recorded in 42.8% (p = 0.001). In group 1, the NT-proBNP level significantly (p = 0.034) decreased by 34%, while in group 2, a significant (p = 0.002) increase in biomarker levels was revealed by 35.5%. In the group of patients receiving therapy with valsartan/sacubitril an increase in LVEF (p = 0.007) was revealed by 12.5%. In group 1, an increase in exercise tolerance was achieved in the form of a significant (p = 0.012) increase in the distance of the six-minute walk test by 18.2%, while in group 2, the six-minute walk distance decreased by 19.2% (p = 0.034). In the subgroup of patients receiving CPAP therapy in combination with valsartan/sacubitril therapy (n=8), LVEF increased by 11.6% (p = 0.043), the six-minute walk test distance increased by 29.7% (p = 0.046), and NT-proBNP decreased by 22.5% (p = 0.039), while in the group of patients who received only CPAP therapy (n=19).

Conclusion. The most significant slowdown in the rate of progression of CHF in patients with AH associated with OSA, an increase in exercise tolerance, as well as the most pronounced tendency to the reverse development of pathological echocardiographic changes in the myocardium when using valsartan/sacubitrile in drug therapy in combination with effective hardware CPAP therapy.

Untargeted Metabolomic Profiling of Liver in a Chronic Intermittent Hypoxia Mouse Model

Obstructive sleep apnea (OSA) has been demonstrated to be associated with liver injury. Nevertheless, the mechanisms linking the two disorders remain largely unexplored to date. Based on UHPLC/Q-TOF MS platform, the present study aimed to study the hepatic metabolomic profiling in a chronic intermittent hypoxia (CIH) mouse model to identify altered metabolites and related metabolic pathways. C57BL/6 Mice (n = 12 each group) were exposed to intermittent hypoxia or control conditions (room air) for 12 weeks. At the end of the exposure, liver enzymes and histological changes were assessed. Untargeted metabolomics approach by UHPLC/Q-TOF MS and orthogonal partial least squares-discriminant analysis (OPLS-DA) were applied to screen altered metabolites in mice liver. Bioinformatics analyses were applied to identify the related metabolic pathways. CIH treatment caused a remarkable liver injury in mice. A total of 27 differential metabolites in negative ion mode and 44 in positive ion mode were identified between the two groups. These metabolites were correlated to multiple biological and metabolic processes, including various amino acid metabolism, membrane transport, lipid metabolism, carbohydrate metabolism, nucleotide metabolism, ferroptosis, etc. three differential metabolites including glutathione, glutathione disulfide, arachidonic acid (peroxide free) were identified in the ferroptosis pathway. CIH was associated with a significant metabolic profiling change in mice liver. The metabolites in amino acid metabolism, membrane transport, lipid metabolism, carbohydrate metabolism, nucleotide metabolism, and ferroptosis played an important role in CIH-induced liver injury. These findings contribute to a better understanding of the mechanisms linking OSA and liver injury and help identify potential therapeutic targets.

Obstructive sleep apnea and the risk of mortality in patients with lung cancer: a meta-analysis

PURPOSE

Prior reports have examined the relationship between obstructive sleep apnea (OSA) and the mortality rate of lung cancer. However, the findings remain controversial. The present meta-analysis was performed to assess the relationship between OSA and increased risk of mortality in patients with lung cancer.

METHODS

PubMed, Web of Science, and Embase were systematically searched for the correlative studies. Data were analyzed and pooled to evaluate odds ratios (ORs) of lung cancer mortality related to OSA.

RESULTS

From 249 identified studies, 3 met inclusion criteria and were analyzed, including 67 patients with lung cancer and comorbid OSA and 45 patients with lung cancer and no OSA. The meta-analysis indicated that OSA was not significantly correlated with mortality rate in lung cancer (OR = 2.005, 95% CI = 0.703 to 5.715, z = 1.30, p = 0.193). There was no significant publication bias according to Begg's tests (p = 0.296) and Egger's tests (p = 0.097).

CONCLUSION

This meta-analysis suggests that OSA is not significantly correlated with the mortality rate in lung cancer.

Effects of Exercise in Patients with Obstructive Sleep Apnoea

Obstructive sleep apnoea (OSA) constitutes a public health problem, with various systemic consequences that can increase cardiovascular morbidity and mortality as well as increase healthcare expenditure. This review discusses the rationale and effects of using general physical exercise, oropharyngeal exercises, and respiratory muscle training as an adjunctive treatment for patients with sleep apnoea. The recommended treatment for OSA is the use of continuous positive airway pressure, which is a therapy that prevents apnoea events by keeping the airways open. In the last decade, coadjuvant treatments that aim to support weight loss (including diet and physical exercise) and oropharyngeal exercises have been proposed to lower the apnoea/hypopnoea index among patients with OSA. Based on the available evidence, health professionals could decide to incorporate these therapeutic strategies to manage patients with sleep apnoea.

Owner reported breathing scores, accelerometry and sleep disturbances in brachycephalic and control dogs: A pilot study

OBJECTIVES

To compare physical activity and length and quality of sleep between brachycephalic dogs and a control population.

METHODS

Brachycephalic and control dogs were prospectively enrolled. Length of activity and sleep were determined via accelerometer use. Owners completed a questionnaire regarding typical daily activity, sleep patterns and an 'owner reported breathing score (ORBS)'. One hour of normal home sleep was recorded for each dog, and a veterinary observer subjectively scored the dogs' sleep quality.

RESULTS

Twenty brachycephalic and 15 control dogs were included. There were no differences between age and weight. Owners reported brachycephalic dogs to be less active (p = 0.022) and have higher ORBS (p < 0.001) compared to control dogs. Brachycephalic dogs had increased sleep disturbances compared to control dogs (p = 0.001), and video sleep score was positively correlated with increased sleep disturbances (r² = 0.47, p = 0.007). There were no differences in active and sleep times based on accelerometry between groups.

CONCLUSION

Brachycephalic dogs have more disturbed sleep, which may have negative implications on welfare, but there were no differences in activity or length of sleep between groups. There is evidence that signs suggestive of brachycephalic obstructive airway syndrome (BOAS) as assessed by ORBS is correlated with poorer sleep quality, indicating that reduced sleep quality is part of BOAS. Owners may underestimate disturbed sleep or may perceive disturbed sleep to be normal.

Does nocturnal use of a complete denture interfere with the degree of obstructive sleep apnea? A systematic review and meta-analysis

BACKGROUND

The impact of a complete denture on obstructive sleep apnea is not well understood. Therefore, this study aimed to evaluate the relationship between nighttime use of complete dentures and obstructive sleep apnea and determine if wearing a complete denture during sleep changes the degree of obstructive sleep apnea.

METHODS

This systematic review followed the notification items for Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) and was recorded in the International Prospective Registry of Systematic Reviews (PROSPERO) under number CRD42020183167. An electronic search in the PubMed/MEDLINE, Scopus, and Cochrane Library databases for articles published until September 2020 was conducted. The search strategy used the terms (complete denture OR denture OR edentulous OR edentulism) AND (quality of sleep OR sleep OR apnea OR obstructive sleep apnea). Only prospective, retrospective, controlled, and randomized clinical studies of patients wearing complete dentures, studies comparing sleep with and without the prosthesis, and studies in which patients were diagnosed with obstructive sleep apnea by polysomnography were included in the review.

RESULTS

In total, four articles were selected for the qualitative and quantitative analyses. A total of 144 patients, with an average age of 60 years, were studied. The meta-analysis showed that there was no statistical difference in the apnea-hypopnea index between using and not using the prosthesis during sleep.

CONCLUSIONS

The use of complete dentures during sleep does not influence the degree of obstructive sleep apnea.

Association between lung function decline and obstructive sleep apnoea: the ALEC study

Purpose

To study changes in lung function among individuals with a risk of obstructive sleep apnoea (OSA), and if asthma affected this relationship.

Methods

We used data from the European Community Respiratory Health Survey II and III, a multicentre general population study. Participants answered questionnaires and performed spirometry at baseline and 10-year follow-up (n = 4,329 attended both visits). Subjects with high risk for OSA were identified from the multivariable apnoea prediction (MAP) index, calculated from BMI, age, gender, and OSA symptoms at follow-up. Asthma was defined as having doctor’s diagnosed asthma at follow-up. Primary outcomes were changes in forced expiratory volume in 1 s (FEV1) and forced vital capacity (FVC) from baseline to follow-up.

Results

Among 5108 participants at follow-up, 991 (19%) had a high risk of OSA based on the MAP index. Participants with high OSA risk more often had wheeze, cough, chest tightness, and breathlessness at follow-up than those with low OSA risk. Lung function declined more rapidly in subjects with high OSA risk (low vs high OSA risk [mean ± SD]: FEV1 = − 41.3 ± 24.3 ml/year vs − 50.8 ± 30.1 ml/year; FVC = − 30.5 ± 31.2 ml/year vs − 45.2 ± 36.3 ml/year). Lung function decline was primarily associated with higher BMI and OSA symptoms. OSA symptoms had a stronger association with lung function decline among asthmatics, compared to non-asthmatics.

Conclusion

In the general population, a high probability of obstructive sleep apnoea was related to faster lung function decline in the previous decade. This was driven by a higher BMI and more OSA symptoms among these subjects. The association between OSA symptoms and lung function decline was stronger among asthmatics.

Electronic supplementary material

The online version of this article (10.1007/s11325-020-02086-1) contains supplementary material, which is available to authorized users.

Effects on obstructive sleep apnea severity following a tailored behavioral sleep medicine intervention aimed at increased physical activity and sound eating: an 18-month follow-up of a randomized controlled trial

STUDY OBJECTIVES

Positive effects have been reported following a behavioral sleep medicine (BSM) intervention targeting physical activity and eating behavior in addition to continuous positive airway pressure (CPAP) treatment in patients with obstructive sleep apnea (OSA). Long-term follow-up remains to be explored. The aim was to examine the long-term effects of a tailored BSM intervention addressing physical activity and eating behavior in addition to CPAP treatment in patients with moderate to severe OSA combined with overweight and physical inactivity. Further, the aim was to identify variables at baseline, associated with treatment success regarding OSA severity.

METHODS

Sixty participants (body mass index: 34.5 ± 5.0 kg/m²; apnea-hypopnea index [AHI]: 43.7 ± 21.2 events/h) completed the randomized controlled trial with a follow-up at 18 months. The participants were randomized to either a control group treated with CPAP or an experimental group treated with CPAP and a BSM intervention targeting physical activity and eating behavior changes. OSA was categorized as mild (AHI: 5 to <14.9 events/h), moderate (AHI: 15 to <29.9 events/h), or severe (AHI ≥30 events/h).

RESULTS

Being in the experimental group was associated with a larger improvement (B = -9.353, P = .029) in AHI at the 18-month follow-up compared with being in the control group when adjusting for baseline AHI and body mass index. Improvement in OSA category occurred more frequently in the experimental group participants (n = 11; 36.7%) compared with the control group (n = 2; 6.7%). Deterioration in OSA category was found in 1 (3.3%) participant in the experimental group and 3 (10%) in the control group.

CONCLUSIONS

The importance of a BSM intervention as an adjunct treatment in patients with OSA is emphasized due to its long-term benefits.

CLINICAL TRIAL REGISTRATION

Registry: ClinicalTrials.gov; Name: Lifestyle changes in obstructive sleep apnea; Identifier: NCT01102920.

Validation of fatty liver index and hepatic steatosis index for screening of non-alcoholic fatty liver disease in adults with obstructive sleep apnea hypopnea syndrome

Background:

Obstructive sleep apnea hypopnea syndrome (OSAHS) is a contributing factor for non-alcoholic fatty liver disease (NAFLD). Non-invasive algorithms including fatty liver index (FLI) and hepatic steatosis index (HSI) have been used as a screening test for NAFLD in epidemiologic studies. The aim of this study is to compare the diagnostic accuracy of FLI and HSI for NAFLD detection in adults with OSAHS.

Methods:

We enrolled consecutive adult subjects who were newly diagnosed with OSAHS from March 2016 to January 2018. NAFLD was diagnosed by ultrasonography. The accuracy and cut-off point of the FLI and HSI to detect NAFLD were assessed by analyzing the area under the receiver operating characteristic (AUROC) curve and the maximum Youden index analysis, respectively.

Results:

The 326 subjects were diagnosed as NAFLD according to ultrasound findings, while 105 subjects who had normal abdominal ultrasonography were grouped as controls. Both FLI and HSI values were significantly higher in patients with NAFLD compared with controls. The AUROC of FLI and HSI for predicting NAFLD was 0.802 (95% confidence interval [CI] 0.762–0.839) and 0.753 (95% CI 0.710–0.793), respectively. The AUROC of FLI was significantly higher than that of HSI (P = 0.0383). The optimal cut-off value of FLI and HSI was 60 (sensitivity 66% and specificity 80%) and 35 (sensitivity 81% and specificity 60%), respectively.

Conclusions:

Both FLI and HSI can serve as screening tools for NAFLD in OSAHS adults. The FLI shows better performance in diagnosing NAFLD than HSI.

Trial registration:

Chinese Clinical Trial Registry (No. ChiCTR-OOB-15007253), http://www.chictr.org.cn/showproj.aspx?proj=11606.

Obstructive sleep apnea and Parkinson's disease: characteristics and associated factors

ABSTRACT Obstructive sleep apnea (OSA) occurs in up to 66% of Parkinson's disease (PD) patients, higher than in the general population. Although it is more prevalent, the relationship between OSA and PD remains controversial, with some studies confirming and others denying the relationship of OSA with some risk factors and symptoms in patients with PD. Objective: To determine the factors associated with OSA in PD patients com DP. Methods: A cross-sectional study was performed with 88 consecutive patients with PD from the outpatient clinic. Participants underwent clinical interviews with neurologists and a psychiatrist, assessment using standardized scales (Epworth Sleepiness Scale, Parkinson's Disease Questionnaire, Pittsburgh Sleep Quality Index and, for individuals with a diagnosis of restless legs syndrome/Willis-Ekbom disease, the International Restless Legs Syndrome Rating Scale), and video-polysomnography. Results: Individuals with PD and OSA were older and had less insomnia than those with PD without OSA. Regarding the polysomnographic variables, we observed a lower percentage of stage N3 sleep, a higher arousal index, and a higher oxygen desaturation index in those individuals with OSA, relative to those without OSA. In the multivariate analysis, only the percentage of stage N3 sleep and the oxygen desaturation index were significantly different. Besides this, most of the PD patients with OSA had a correlation with sleeping in the supine position (58% of OSA individuals). Conclusion: The PD patients showed a high prevalence of OSA, with the supine position exerting a significant influence on the OSA in these patients, and some factors that are associated with OSA in the general population did not seem to have a greater impact on PD patients.

Effects of CPAP on visceral adipose tissue in patients with obstructive sleep apnea: a meta-analysis

PURPOSE

The efficacy of obstructive sleep apnea (OSA) treatment with continuous positive airway pressure (CPAP) on visceral adipose tissue (VAT) yielded conflicting results. This meta-analysis was performed to assess whether OSA treatment with CPAP could reduce VAT.

METHODS

The PubMed, Cochrane Library, Embase, and Web of Science were searched before April 2019. Information on characteristics of study participants, pre- and post-CPAP treatment of VAT, and study design was utilized for analysis. Standardized mean difference (SMD) and 95% confidence interval (CI) were used to fully analyze the overall effects. Eleven studies were obtained and the meta-analysis was performed using RevMan v.5.2 and STATA 12.0.

RESULTS

A total of 11 studies (16 cohorts) were pooled into meta-analysis, which included 398 patients. The value of VAT before and after CPAP treatment showed no change in OSA patients (SMD = - 0.02, 95% CI - 0.16 to 0.12, z = 0.24, p = 0.81). Subgroup analyses were further conducted, which revealed that age, gender distribution, baseline body mass index, daily duration, CPAP therapy duration, measure, sample size, and study design did not affect the results.

CONCLUSIONS

This meta-analysis revealed that CPAP therapy has no effect on VAT in OSA patients. Further large-scale, well-designed randomized controlled trials are required to address this issue.

Evaluation of metabolic profile and C-reactive protein concentrations in brachycephalic dogs with upper airway obstructive syndrome

Background

Brachycephalic dogs have abnormal breathing patterns similar to those in humans with obstructive sleep apnea syndrome. Obstructive sleep apnea syndrome is associated with dyslipidemia, hyperglycemia, and insulin resistance. Despite the fact that anatomic and functional alterations are well described in brachycephalic dogs, little is known about the consequences of upper airway obstruction on systemic inflammatory response and metabolic profile.

Objectives

To describe history, clinical presentation, and anatomic abnormalities; to evaluate systemic inflammatory response and metabolic profile; and to identify possible associations among clinical signs, anatomic abnormalities, inflammatory response, and metabolic profile in brachycephalic dogs with airway obstruction.

Animals

Thirty purebred brachycephalic dogs with brachycephalic airway obstructive syndrome (BAOS).

Methods

Prospective study. The following information was recorded and studied: respiratory and digestive signs, airway and digestive endoscopic anomalies, presence or absence of tracheal hypoplasia, histologic evaluation of gastrointestinal tract biopsy specimens, serum concentrations of C‐reactive protein (CRP), fructosamine, insulin, glucose, triglyceride, cholesterol, and plasma concentrations of lipoprotein classes.

Results

A high proportion of dogs (76.7%) had gastrointestinal signs. Esophageal deviation, atony of the cardia of the stomach, and distal esophagitis were the most common endoscopic anomalies detected. Twenty‐six (86.6%) dogs had different degrees of laryngeal collapse. Gastrointestinal histologic evaluation identified mostly chronic inflammation. Glucose, fructosamine, triglycerides, cholesterol, CRP, pre‐beta, beta lipoproteins, and chylomicrons were increased to a variable extent. Significant associations among clinical signs, anatomic abnormalities, CRP, and metabolic profile were not found.

Conclusion and Clinical Importance

Despite the presence of inflammation and some mild metabolic derangements, the clinicopathological variables evaluated did not offer valuable information in dogs with BAOS.

Weight Management in Obstructive Sleep Apnea: Medical and Surgical Options

Obesity plays a pivotal role in the pathogenesis of obstructive sleep apnea (OSA) and as an exacerbating factor of OSA. Given the interlinking relationship of obesity and OSA, treatment of obesity is fundamental in the management of OSA. Weight loss of 7% to 11% significantly improves OSA with remission seen with greater weight loss. Weight loss also ameliorates the constellation of other obesity-related metabolic conditions, reducing the overall cardiovascular risk in an obese person with OSA. This article discusses specific weight loss interventions effective in improving OSA, including lifestyle interventions with dietary modification and physical activity, pharmacotherapy, and bariatric surgery.

A meta-analysis of the association between gout, serum uric acid level, and obstructive sleep apnea

Previous epidemiological investigations have evaluated the association between gout, serum uric acid levels, and obstructive sleep apnea syndrome (OSAS), but with inconsistent results. We conducted this meta-analysis aiming at providing clear evidence about whether OSAS patients have higher serum uric acid levels and more susceptible to gout. Relevant studies were identified via electronic databases from inception to December 17, 2018. Study selection was conducted according to predesigned eligibility criteria, and two authors independently extracted data from included studies. The hazard ratio (HR) and weighted mean difference (WMD) and their corresponding 95% confidence interval (CI) were derived using random-effects models. We conducted meta-, heterogeneity, publication bias, sensitivity, and subgroup analyses. Eighteen studies, involving a total of 157,607 individuals (32,395 with OSAS, 125,212 without OSAS) and 12,262 gout cases, were included. Results show that serum uric acid levels are elevated in patients with OSAS (WMD = 52.25, 95% CI 36.16-64.33); OSAS did not reach statistical significance as a predictor of gout (but there was a trend, HR = 1.25, 95% CI 0.91-1.70) and that the association between OSAS and serum uric acid was quite robust. OSAS may be a potential risk factor for hyperuricemia and the development of gout and thus, effective OSAS therapy may present as a valuable preventive measure against gout. Still, it is vital to undertake clinical studies with better designing to corroborate these associations and shed new light on it.

Effects of a Combined Community Exercise Program in Obstructive Sleep Apnea Syndrome: A Randomized Clinical Trial

Physical activity is associated with a decreased prevalence of obstructive sleep apnea and improved sleep efficiency. Studies on the effects of a comprehensive exercise program in a community setting remain limited. Our objective was to investigate the effects of a combined physical and oropharyngeal exercise program on the apnea-hypopnea index in patients with moderate to severe obstructive sleep apnea. This was a randomized clinical trial where the intervention group followed an eight-week urban-walking program, oropharyngeal exercises, and diet and sleep recommendations. The control group followed diet and sleep recommendations. A total of 33 patients were enrolled and randomized and, finally, 27 patients were included in the study (IG, 14; CG, 13) Obstructive sleep apnea patients were analyzed with a median age of 67 (52–74) and median apnea-hypopnea index of 32 events/h (25–41). The apnea-hypopnea index did not differ between groups pre- and post-intervention. However, in intervention patients younger than 60 (n = 6) a reduction of the apnea-hypopnea index from 29.5 (21.8–48.3) to 15.5 (11–34) events/h (p = 0.028) was observed. While a comprehensive multimodal program does not modify the apnea-hypopnea index, it could reduce body weight and increase the walking distance of patients with moderate to severe obstructive sleep apnea. Patients younger than 60 may also present a decreased apnea-hypopnea index after intervention.

Sleep-Disordered Breathing in Hospitalized Geriatric Patients with Mild Dementia and Its Association with Cognition, Emotion and Mobility

Sleep-disordered breathing (SDB) is an emerging dementia risk factor. Data on the prevalence of SDB in dementia patients and its association with cognitive impairment is so far only based on patients with severe dementia. In 101 geriatric patients mostly with mild dementia recruited on German geriatric wards, SDB was assessed during overnight polygraphy in the patient room with a portable sleep apnea examination device and associations of SDB severity with severity of impairment in cognitive and emotional function as well as mobility were investigated. We also elucidated which factors influence compliance of SDB diagnostics. In 82 of the 101 dementia patients (81.2%), SDB could be assessed. Of those, only 12.2% had an apnea-hypopnea index (AHI) < 5/h demonstrating the absence of SDB. 40.2% exhibited 5/h ≤ AHI < 15/h representing mild SDB, and 47.6% revealed an AHI ≥ 15/h representing moderate/severe SDB. Patients in these three AHI categories did not significant differ from each other in demographical and clinical characteristics. Patients with an AHI ≥ 15/h particularly often presented with heart failure and vitamin D deficiency. We observed a low to moderate association between severity of SDB and severity of dementia. Tolerance of the nasal airflow sensor of at least 6 h was present in less than one third of all patients. The tolerant group exhibited more symptoms of depression and higher physical fitness compared to the non-tolerant group. We observed a high prevalence of SDB also in geriatric patients with mild dementia underlining the importance of SDB screening in the elderly.

Association of continuous positive airway pressure with F2-isoprostanes in adults with obstructive sleep apnea: a meta-analysis

PURPOSE

Obstructive sleep apnea (OSA) is associated with increased F2-isoprostanes, a reliable standard biomarker of oxidative stress. Treatment with continuous positive airway pressure (CPAP) is effective for all degrees of OSA. However, it remains unknown whether treatment with CPAP will decrease F2-isoprostanes. A meta-analysis was conducted to determine the effect of CPAP treatment on F2-isoprostanes among patients with OSA.

METHODS

The PubMed, Embase, Web of Science, and Cochrane library were searched before September, 2018. Eight articles assessing indices of F2-isoprostanes from various body fluids were identified. Pooled standardized mean difference (SMD) and weighted mean difference (WMD) were appropriately calculated through fixed or random effects models after assessing between-study heterogeneity.

RESULTS

A total of 4 studies with 108 patients were pooled for exhaled breath condensate (EBC) F2-isoprostanes; 3 studies with 93 patients were pooled for serum or plasma F2-isoprostanes; and 3 studies with 102 patients were pooled for urinary F2-isoprostanes. A significant decrease of EBC F2-isoprostanes was observed after CPAP treatment (WMD = 2.652, 95% CI = 0.168 to 5.136, z = 2.09, p = 0.036), as well as serum or plasma F2-isoprostanes and urinary F2-isoprostanes (SMD = 1.072, 95% CI = 0.276 to 1.868, z = 2.64, p = 0.008 and WMD = 85.907, 95% CI = 50.443 to 121.372, z = 4.75, p = 0.000, respectively).

CONCLUSIONS

This meta-analysis suggested that CPAP therapy was associated with a significant decrease in F2-isoprostanes in patients with OSA.

Clues to the Pathophysiology of Sudden Cardiac Death in Obstructive Sleep Apnea

BACKGROUND

Risk assessment of sudden cardiac death (SCD) is multifactorial and complex, especially among individuals without established cardiovascular disease. There are insufficiently investigated conditions that can affect arrhythmogenesis. One such condition is obstructive sleep apnea (OSA) syndrome, which is not on the list of risk factors of the Russian National Society of Arrhythmology.

OBJECTIVE

The aim of this review article is to discuss clues to the pathophysiology of SCD in OSA subjects.

METHODS

We searched the literature for data reporting the impact of apnea on arrhythmogenesis. The preferred languages were English and Russian. The most important clinical reports, as well as biochemistry and pathophysiology guides, were selected for inclusion in the review.

RESULTS

It was clearly observed in the searched literature that OSA is the crucial aspect of arrhythmogenesis. Among the clues are intermittent nocturnal hypoxia, reactive oxygen species, cardiomyocyte metabolism disturbances, myocardial electric heterogeneity, and intrathoracic pressure changes.

CONCLUSION

This review emphasizes the importance of the inclusion of OSA in the list of risk factors of the Russian National Society of Arrhythmology.

Effect of sodium glucose cotransporter 2 inhibitors on obstructive sleep apnea in patients with type 2 diabetes

Obstructive sleep apnea syndrome (OSAS) is often associated with metabolic disorders such as obesity and type 2 diabetes and may contribute to cardiovascular events. A novel class of antidiabetic drugs, the sodium glucose cotransporter 2 inhibitors (SGLT2i) reduce body weight (BW), although there is limited data on their impact on OSAS. We therefore evaluated the effect of SGLT2i on OSAS in patients with type 2 diabetes. The presented study was a retrospective design in 18 patients with type 2 diabetes with OSAS (4 males, age range 39-81 yr) administrated a SGLT2i. HbA1c, BW, body mass index (BMI), blood pressure (BP) and apnea hypopnea index (AHI) were evaluated before and after SGLT2i administration. The relationships between the reduction in AHI and the other variables were examined using Pearson correlation analysis. We have got result that SGLT2i reduced AHI from 31.9 ± 18.0 to 18.8 ± 11.5 events per hr (p = 0.003). HbA1c, BW and BMI decreased significantly, whereas BP did not. The Pearson correlation analysis showed a significant relationship between the reduction in AHI and pre-administration of AHI. In conclusion, SGLT2i reduced not only HbA1c, BW and BMI but also AHI significantly and therefore has potential as an effective treatment of OSAS.

Symptoms of Daytime Sleepiness and Sleep Apnea in Liver Cirrhosis Patients

Background/propose. Sleep disturbance and excessive daytime sleepiness (EDS) have been reported in patients with hepatic cirrhosis with no hepatic encephalopathy (HE). The objective of this study was to evaluate daytime sleepiness and risk of obstructive sleep apnea (OSA) among liver cirrhosis patients.

MATERIAL AND METHODS

A cross-sectional study was conducted at King Abdulaziz Medical City (KAMC)-Riyadh over a period of six months, using a structured questionnaire that investigated: 1) Sleep patterns and daytime sleepiness using the Epworth Sleeping Scale (ESS), and 2) The risk for sleep apnea using the Berlin Questionnaire (BQ). We enrolled patients with a confirmed diagnosis of liver cirrhosis who were being followed at the hepatology and pre-liver transplant clinics.

RESULTS

We enrolled 200 patients with liver cirrhosis, 57.5% of whom were male. The mean age was 60 (± SD 12.2). The reported prevalence of EDS, OSA, and both EDS and OSA were 29.5%, 42.9%, and 13.6%, respectively. The prevalence of EDS was higher in patients with Hepatitis-C and patients with DM, who experienced short sleep duration. We did not find any association between the severity of liver disease and EDS or OSA as measured by Child-Pugh scores (CPS).

CONCLUSIONS

The risk of OSA and EDS is high among liver cirrhosis patients. Those patients with cirrhosis secondary to Hepatitis C are at higher risk of EDS and OSA. Both EDS and OSA affect patients designated as CPS Class A more frequently than patients designated as CPS Class B.

Prevalence, Risk Factors, Outcomes, and Treatment of Obstructive Sleep Apnea in Patients with Cerebrovascular Disease: A Systematic Review

BACKGROUND

Obstructive sleep apnea (OSA) is known to increase the risk of cerebrovascular disease (CVD), and patients with CVD have high incidence of OSA. The study aimed to systematically evaluate the prevalence of OSA in patients with CVD.

MATERIALS AND METHODS

Medline, Embase, Science Citation Index, Wanfang, CNKI, and Wiley Online Library were thoroughly searched to identify relevant studies. Random-effects models were used to calculate the pooled rate estimates. Meta-regression and subgroup analysis were performed to explore potential sources of heterogeneity.

RESULTS

Thirty-seven studies with 3242 patients were analyzed. The prevalence of OSA (apnea hypopnea index [AHI] >10) ranged from 34.5% to 92.3%, the random-effects pooled prevalence was 61.9%. Furthermore, the prevalence of sleep disordered breathing (SDB) with AHI  greater than  5 was 70.4%, with AHI greater than 20 was 39.5%, and with AHI greater than 30 was 30.1%. Only 8.3% of the SDB was primarily central apnea. Seventeen studies reported risk factors for OSA, 6 of which used multivariate analyses to extract risk factors. In univariate meta-regression analysis, male had higher prevalence than female (P = .041). OSA was associated with increased length of hospitalization in 2 studies, and 1 long-term study reported severe sleep apnea was associated with poor functional outcome. Among the 5 studies on treatment, 3 indicated that early treatment with CPAP was effective; the remaining studies did not find benefit from CPAP treatment and reported the CPAP acceptance was poor.

CONCLUSIONS

There is high prevalence of OSA in patients with CVD (61.9%). Therefore, accurate diagnosis and treatment to OSA is very important so as to prevent CVD.

The importance of calprotectin levels in obstructive sleep apnea syndrome severity

BACKGROUND

Obstructive sleep apnea syndrome (OSAS) is mostly seen in adult populations. It is known that increased levels of several inflammatory mediators play roles in OSAS and related comorbidities. Calprotectin is an inflammatory mediator that increases in some diseases such as Behçet's syndrome, bowel diseases and cardiovascular and cerebrovascular diseases.

AIMS

The purpose of this study was to investigate whether calprotectin can be used as a biomarker in OSAS by determining the relation between serum calprotectin levels and OSAS severity.

STUDY DESIGN

Cohort study.

METHODS

A prospective study was planned. Eighty-three patients undergoing polysomnography were included in the study and evaluated prospectively. Thirty patients were classified as non-OSAS (group 1), 18 as mild OSAS (group 2), 15 as moderate OSAS (group 3) and 20 as severe OSAS (group 4). Calprotectin values were measured in the non-OSAS patients (group 1) and in the patients with OSAS (groups 2, 3 and 4). The OSAS groups were also compared with each other.

RESULTS

Serum calprotectin values ranged between 70.61 and 1468.04 ng/ml. No significant difference in calprotectin levels was found between the OSAS and normal groups. However, statistically significantly increased calprotectin values were determined in the severe OSAS group (group 4) when all groups were compared.

CONCLUSION

Calprotectin values were elevated in OSAS patients and it can be used as a marker of severe OSAS. Future studies can support our study.

Obstructive sleep apnea as a risk factor associated with difficult airway management - A narrative review

STUDY OBJECTIVE

The association between obstructive sleep apnea (OSA) and difficult airway had been studied in various clinical trials but the relationship between the two conditions has not been clearly established. The objective of this narrative review is to determine if OSA is a risk factor associated with difficult airway.

DESIGN

The OVID Medline in process, Medline (vis Pub Med), EMBASE, Cochrane Central Register of Controlled Trials, Cochrane Database of Systematic Reviews, Web of Science and SCOPUS were searched up to April 2016 using specific keywords. Inclusion criteria were: [1] airway management in patients with a diagnosis of OSA, [2] comparison of airway management between OSA and non-OSA patients, [3] publications or abstracts in the English language. The incidence of difficult airway between OSA and non-OSA patients was compared using Chi-square analysis or Fisher's exact test.

MAIN RESULTS

Ten studies were included in the final review. Overall, the incidence of difficult tracheal intubation was higher in OSA patients versus non-OSA patients [56/386 (14.5%) vs. 69/897 (7.7%); P=0.0002]. OSA patients also have a higher incidence of difficult mask ventilation [115/4626 (2.5%) vs. 471/64,684 (0.7%); P<0.0001]. Compared to non-OSA patients, OSA was not associated with difficulty in the use of a supraglottic airway (SGA) device [10/663 (1.5%) vs. 162/15,171 (1.1%); P=0.38]. No studies compared difficult surgical airway in OSA and non-OSA patients.

CONCLUSIONS

OSA was found to be a risk factor associated with difficult tracheal intubation and difficult mask ventilation. There was no association between OSA and difficult SGA use.

Effect of continuous positive airway pressure (CPAP) therapy on IL-23 in patients with obstructive sleep apnea

Obstructive sleep apnea syndrome (OSAS) is a common sleep disorder characterized by repeated episodes of apnea and hypopnea during sleep. Continuous positive airway pressure (CPAP) is the most effective method for treating OSAS and alleviating the patients' symptoms. The aim of this study was to assess the effect of 3-month CPAP therapy on serum levels of IL-23 in patients with OSAS. Twenty-three patients with newly diagnosed moderate-to-severe OSAS who had not yet started nasal CPAP treatment were prospectively enrolled. All of the subjects underwent simple spirometry and an overnight sleep study. Twenty-seven healthy individuals without OSAS were also recruited as the control group. Serum IL-23 and C-reactive protein (CRP) levels were measured before and after 3 months of CPAP therapy. There was no significant difference between moderate and severe OSAS patients in IL-23 and CRP, but both parameters were significantly higher than control group. The CPAP treatment produced a significant decrease in the levels of the inflammatory mediators CRP and IL-23 in patients. Changes in IL-23 were positively correlated with changes in AHI and in CRP. In conclusion, based on these results, serum IL-23 levels reflect OSAS-related systemic inflammation and are a useful marker for improvement in OSAS following CPAP therapy.

Severe brachycephalic obstructive airway syndrome is associated with hypercoagulability in dogs

We evaluated whether dogs with severe brachycephalic obstructive airway syndrome (BOAS) developed a hypercoagulable state similar to people with obstructive sleep apnea. Five dogs with grade 3 BOAS were included as well as 5 healthy control Labrador Retrievers. Venous blood samples were collected from each dog for performance of thromboelastography and determination of hematocrit and platelet count. Groups were compared using a t-test, with p < 0.05 considered significant. Thromboelastography results identified that all BOAS dogs were hypercoagulable compared to the Labradors, having significantly shortened clotting time with increased angle, maximal amplitude, and clot rigidity. BOAS dogs also had evidence of delayed fibrinolysis. These results are consistent with, but more severe than, those previously documented in apparently healthy Bulldogs. Together, these findings support the presence of a hypercoagulable state in brachycephalic dogs, and suggest that this state is amplified by increasing severity of BOAS.

Patients with Obstructive Sleep Apnea Display Decreased Flow-Mediated Dilatation: Evidence from a Meta-Analysis

Background

Endothelial dysfunction, which can be measured by flow-mediated dilatation (FMD), is an early clinical marker of atherosclerosis, which is considered to be the main cause of the observed cardiovascular complications in obstructive sleep apnea (OSA) patients. The association between OSA and endothelial dysfunction has been reported in a number of studies; however, the findings are not entirely consistent. Our aim was to meta-analytically synthesize the existing evidence to explore the association between OSA and endothelial dysfunction.

Material/Methods

Data from PubMed, EMBASE, the Cochrane library, and Google Scholar for all trials that investigated the relationship between endothelial dysfunction and OSA were systematically reviewed. The minimum inclusion criteria for the studies were reporting of the Apnea-Hypopnea Index (AHI) and FMD measurements (as an indicator of endothelial dysfunction) for both OSA and control groups. Data from case-control studies that met the inclusion criteria were extracted.

Results

Twenty-eight studies comprising a total of 1496 OSA patients and 1135 controls were included in the meta-analysis. A random-effects model was used. The weighted mean difference in the FMD measurements was −3.07 and the 95% confidence interval was −3.71 to −2.43 (P<0.01). Meta-regression analysis showed that age, sex, body mass index (BMI), blood pressure, glucose, high-density lipoprotein (HDL) cholesterol, and low-density lipoprotein (LDL) cholesterol did not explain the heterogeneity.

Conclusions

This meta-analysis showed that patients with OSA have decreased FMD, which may contribute to the development of atherosclerosis.

Obstructive Sleep Apnea: Epidemiology and Portuguese patients profile

INTRODUCTION

Obstructive Sleep Apnea (OSA) is characterized by recurrent episodes of apnea and hypopnea, secondary to collapse of the upper airways during sleep. OSA is frequently associated to cardiovascular complications. In Portugal, its magnitude is unknown.

METHODS

In 2014 a cross-sectional study was performed using the Portuguese General Practitioner (GP) Sentinel Network (Rede Médicos Sentinela). Participants GP reported all OSA cases diagnosed and registered in their lists of users on the 31 December 2013. Frequency of OSA has been estimated by sex and age. OSA patients were also characterized by method of diagnosis, treatment, and underlying conditions. Association between risk factors and severe OSA (odds ratio) was calculated using a logistic regression model adjusting confounding.

RESULTS

Prevalence of OSA on the population aged 25 years or more was 0.89% (95 CI: 0.80-1.00%); it was higher in males 1.47% (95 CI: 1.30-1.67%) and in those aged between 65 and 74 (2.35%). Most had severe OSA (48.4%). Hypertension (75.9%), obesity (74.2%) and diabetes mellitus (34.1%) were the most frequent comorbidities. Being a male (OR: 2.6; 95 CI: 1.2-5.8) and having obesity (OR: 4.0; 95 CI: 1.8-8.6) were associated with an increased risk of severe OSA.

CONCLUSION

Found frequency of OSA was lower than other countries estimates, which may be explained by differences on case definition but can also suggest underdiagnosis of this condition as reported by other authors.

Effect of continuous positive airway pressure on liver enzymes in obstructive sleep apnea: A meta-analysis

BACKGROUND

Previous studies have suggested that obstructive sleep apnea (OSA) was associated with nonalcoholic fatty liver disease (NAFLD). However, the impact of OSA treatment using continuous positive airway pressure (CPAP) on liver enzymes remained controversial. This meta-analysis was conducted to determine whether CPAP therapy could reduce liver enzyme levels.

METHODS

Two reviewers independently searched PubMed, Cochrane library, Embase and Web of Science before December 2015. Information on characteristics of subjects, study design and pre- and post-CPAP treatment of serum ALT and AST was extracted for analysis. A total of five studies with seven cohorts that included 192 patients were pooled into meta-analysis.

RESULTS

CPAP was associated with a statistically significant decrease on both ALT and AST levels in OSA patients (WMD = 8.036, 95% CI = 2.788-13.285, z = 3.00, P = .003 and WMD = 4.612, 95% CI = 0.817-8.407, z = 2.38, P = .017, respectively). Subgroup analyses indicated that CPAP therapy was more effective in OSA patients with treatment duration > 3 mo (WMD = 12.374, 95% CI = 2.727-22.020, z = 2.51, P = .012 for ALT and WMD = 7.576, 95% CI = 1.781-13.370, z =2.56, P = .010 for AST).

CONCLUSION

This meta-analysis suggested that CPAP was associated with a statistically significant decrease on liver enzymes in OSA patients. Further large-scale well-designed RCTs with long-term follow-up are required to clarify this issue.

Obstructive sleep apnea is associated with fatty liver index, the index of nonalcoholic fatty liver disease

BACKGROUND AND OBJECTIVES

The relationship between obstructive sleep apnea (OSA) and nonalcoholic fatty liver disease (NAFLD) is gaining increased attention. The aim of the present study was to examine the relationship of OSA with NAFLD defined by an elevated fatty liver index (FLI).

MATERIALS AND METHODS

A total of 319 consecutive patients who underwent standard polysomnography were enrolled. Fasting blood samples were obtained from all patients for biological profile measurements, and demographic data were collected. Values of FLI were determined and assessed as predictors of the presence of NAFLD, as measured by ultrasound. The discriminative ability of FLI was estimated on the basis of the area under the receiver operator characteristic curve.

RESULTS

An FLI of 60 achieved the highest diagnostic accuracy and yielded an area under the receiver operator characteristic curve of 0.822 (95% confidence interval: 0.729-0.916) in the detection of NAFLD. Patients with an FLI of 60 or higher had a significantly lower lowest O2 saturation (73 vs. 83%, P<0.001), a lower mean nocturnal oxygen saturation (93 vs. 95%, P<0.001), a higher apnea-hypopnea index (39.7 vs. 18.4, P<0.001), a higher oxygen desaturation index (39 vs. 10.6, P<0.001), and a higher percentage of sleep time spent with SpO2 less than 90% (4.63 vs. 0.92%, P<0.001) compared with those with FLI less than 60. In multivariate analysis, the presence of OSA was independently associated with elevated FLI after adjusting for confounding factors (odds ratio: 5.141, 95% confidence interval: 1.414-18.696, P=0.013).

CONCLUSION

Our results suggest a positive association between the severity of OSA and NAFLD defined by an elevated FLI, which may serve as a good biomarker for detecting NAFLD in OSA patients.

Effect of liraglutide 3.0 mg in individuals with obesity and moderate or severe obstructive sleep apnea: the SCALE Sleep Apnea randomized clinical trial

BACKGROUND

Obesity is strongly associated with prevalence of obstructive sleep apnea (OSA), and weight loss has been shown to reduce disease severity.

OBJECTIVE

To investigate whether liraglutide 3.0 mg reduces OSA severity compared with placebo using the primary end point of change in apnea-hypopnea index (AHI) after 32 weeks. Liraglutide's weight loss efficacy was also examined.

SUBJECTS/METHODS

In this randomized, double-blind trial, non-diabetic participants with obesity who had moderate (AHI 15-29.9 events h(-1)) or severe (AHI ⩾30 events h(-1)) OSA and were unwilling/unable to use continuous positive airway pressure therapy were randomized for 32 weeks to liraglutide 3.0 mg (n=180) or placebo (n=179), both as adjunct to diet (500 kcal day(-1) deficit) and exercise. Baseline characteristics were similar between groups (mean age 48.5 years, males 71.9%, AHI 49.2 events h(-1), severe OSA 67.1%, body weight 117.6 kg, body mass index 39.1 kg m(-2), prediabetes 63.2%, HbA1c 5.7%).

RESULTS

After 32 weeks, the mean reduction in AHI was greater with liraglutide than with placebo (-12.2 vs -6.1 events h(-1), estimated treatment difference: -6.1 events h(-1) (95% confidence interval (CI), -11.0 to -1.2), P=0.0150). Liraglutide produced greater mean percentage weight loss compared with placebo (-5.7% vs -1.6%, estimated treatment difference: -4.2% (95% CI, -5.2 to -3.1%), P<0.0001). A statistically significant association between the degree of weight loss and improvement in OSA end points (P<0.01, all) was demonstrated post hoc. Greater reductions in glycated hemoglobin (HbA1c) and systolic blood pressure (SBP) were seen with liraglutide versus placebo (both P<0.001). The safety profile of liraglutide 3.0 mg was similar to that seen with doses ⩽1.8 mg.

CONCLUSIONS

As an adjunct to diet and exercise, liraglutide 3.0 mg was generally well tolerated and produced significantly greater reductions than placebo in AHI, body weight, SBP and HbA1c in participants with obesity and moderate/severe OSA. The results confirm that weight loss improves OSA-related parameters.

Perioperative sleep apnea: a real problem or did we invent a new disease?

Depending on the subpopulation, obstructive sleep apnea (OSA) can affect more than 75% of surgical patients. An increasing body of evidence supports the association between OSA  and perioperative complications, but some data indicate important perioperative outcomes do not differ between patients with and without OSA. In this review we will provide an overview of the pathophysiology of sleep apnea and the risk factors for perioperative complications related to sleep apnea. We also discuss a clinical algorithm for the identification and management of OSA patients facing surgery.

Elevated Serum Liver Enzymes in Patients with Obstructive Sleep Apnea-hypopnea Syndrome

BACKGROUND

Obstructive sleep apnea-hypopnea syndrome (OSAS) is associated with elevated liver enzymes and fatty liver. The purpose of this study was to measure serum liver enzyme levels in patients evaluated by polysomnography (PSG) and the factors associated with liver injury in OSAS patients.

METHODS

All patients referred to PSG for evaluation of sleep apnea symptoms between June 2011 and November 2014 were included in this study. Demographic data and PSG parameters were recorded. Serum alanine aminotransferase, aspartate aminotransferase, and gamma-glutamyl transferase levels were systematically measured. OSAS patients were divided into mild, moderate, and severe groups according to the apnea-hypopnea index (AHI) values of 5-14 events/h, 15-29 events/h, and ≥30 events/h.

RESULTS

A total of 540 patients were enrolled in this study; among these patients, 386 were male. Elevated liver enzymes were present in 42.3% of OSAS patients (32.4% in mild/moderate group; 51.0% in severe group) and 28.1% patients without OSAS. Patients with OSAS had higher body mass index (BMI) (P < 0.01). In the bivariate correlation, the liver enzymes level was negatively correlated with age and the lowest arterial oxygen saturation (SaO 2 ), and was positively correlated with BMI, oxygen desaturation index, percent of total time with oxygen saturation level <90% (TS90%), AHI, total cholesterol (TC), and triglyceride (TG). In logistic regression analysis, Age, BMI, TS90%, TC, and TG were included in the regression equation.

CONCLUSIONS

Our data suggest that OSAS is a risk factor for elevated liver enzymes. The severity of OSAS is correlated with liver enzyme levels; we hypothesize that hypoxia is one of main causes of liver damage in patients with OSAS.

Effect of Continuous Positive Airway Pressure on Adiponectin in Patients with Obstructive Sleep Apnea: A Meta-Analysis

Objective

Obstructive sleep apnea (OSA) has been suggested to be associated with low levels of adiponectin. Continuous positive airway pressure (CPAP) is the gold standard treatment for OSA; however, previous studies assessing the effect of CPAP on adiponectin in patients with OSA yielded conflicting results. The present meta-analysis was performed to determine whether CPAP therapy could increase adiponectin levels.

Methods

Two reviewers independently searched PubMed, Cochrane library, Embase and Web of Science before February 2015. Information on characteristics of subjects, study design and pre- and post-CPAP treatment of serum adiponectin was extracted for analysis. Standardized mean difference (SMD) was used to analyze the summary estimates for CPAP therapy.

Results

Eleven studies involving 240 patients were included in this meta-analysis, including ten observational studies and one randomized controlled study. The meta-analysis showed that there was no change of adiponectin levels before and after CPAP treatment in OSA patients (SMD = 0.059, 95% confidence interval (CI) = −0.250 to 0.368, z = 0.37, p = 0.710). Subgroup analyses indicated that the results were not affected by age, baseline body mass index, severity of OSA, CPAP therapy duration, sample size and racial differences.

Conclusions

This meta-analysis suggested that CPAP therapy has no impact on adiponectin in OSA patients, without significant changes in body weight. Further large-scale, well-designed long-term interventional investigations are needed to clarify this issue.

The Association between Obstructive Sleep Apnea and Metabolic Markers and Lipid Profiles

Purpose

The purpose of this study was to investigate the association between apnea-hypopnea index (AHI) and metabolic markers and whether the elevated risk of Metabolic Syndrome (MetS) is related to Obstructive Sleep Apnea (OSA).

Methods

This cross-sectional study recruited 246 male bus drivers from one transportation company in Taiwan. Each participant was evaluated by a polysomnography (PSG) test and by blood lipids examination. Severity of OSA was categorized according to the apnea-hypopnea index (AHI).

Results

The results showed that a 73.3% prevalence of MetS in OSA (AHI > 15) and a 80.0% prevalence of MetS in severe OSA (AHI > 30) were found. After adjusting for confounding variables, an increased level of Body-Mass Index (BMI) and two non-MetS cardiovascular risk factors, total cholesterol/HDL-C ratio and TG/HDL-C ratio was significantly associated with AHI in subjects with severe OSA. MetS was about three times to be present in subjects with severe OSA, even adjusted for BMI.

Conclusions

The findings showed a high prevalence of MetS in OSA among professional drivers, especially in the severe group category. BMI was the major contributing factor to OSA. However, the present study did not find a sensitive clinical marker of a detrimental metabolic profile in OSA patients.

Correlation of cephalometric and anthropometric measures with obstructive sleep apnea severity

Introduction: Patients with obstructive sleep apnea-hypopnea syndrome (OSAHS) often have associated changes in craniofacial morphology and distribution of body fat, either alone or in combination.

Aim: To correlate cephalometric and anthropometric measures with OSAHS severity by using the apnea-hypopnea index (AHI).

Method: A retrospective cephalometry study of 93 patients with OSAHS was conducted from July 2010 to July 2012. The following measurements were evaluated: body mass index (BMI), neck circumference (NC), waist circumference (WC), hip circumference (HC), the angles formed by the cranial base and the maxilla (SNA) and the mandible (SNB), the difference between SNA and SNB (ANB), the distance from the mandibular plane to the hyoid bone (MP-H), the space between the base of the tongue and the posterior pharyngeal wall (PAS), and the distance between the posterior nasal spine and the tip of the uvula (PNS-P). Means, standard deviations, and Pearson's correlation coefficients were calculated and analyzed.

Results: AHI correlated significantly with BMI (r = 0.207, p = 0.047), NC (r = 0.365, p = 0.000), WC (r = 0.337, p = 0.001), PNS-P (r = 0.282, p = 0.006), and MP-H (r = 0.235, p = 0.023).

Conclusion: Anthropometric measurements (BMI, NC, and WC) and cephalometric measurements (MP-H and PNS-P) can be used as predictors of OSAHS severity.

Menopause is associated with self-reported poor sleep quality in women without vasomotor symptoms

OBJECTIVE

The aim of this study was to investigate the relationship between menopause and self-reported sleep quality in Chinese women without vasomotor symptoms.

METHODS

Cross-sectional data were collected from a decoded database of the National Cheng Kung University Hospital. Menopause was defined as absence of menses for at least 12 months or a history of hysterectomy and oophorectomy. Self-reported sleep quality was assessed using the Pittsburgh Sleep Quality Index (PSQI). A higher global PSQI score indicates poorer self-reported sleep quality, and a global PSQI score greater than 5 differentiates poor sleepers from good sleepers.

RESULTS

Of the 1,088 women recruited, 353 (32.4%) were in postmenopause status. Postmenopausal women had higher mean (SD) global PSQI scores (8.0 [3.3] vs. 6.1 [2.2], P < 0.001) and a greater prevalence of poor sleepers (73.1% vs. 60.8%, P < 0.001) compared with premenopausal women. Multivariate linear regression analysis showed that menopause (β = 1.532; 95% CI, 1.135 to 1.949; P < 0.001) and snoring (β = 0.764; 95% CI, 0.299 to 1.228; P = 0.001) were positively associated with global PSQI scores, whereas long sleep duration (β = -0.791; 95% CI, -1.113 to -0.468; P < 0.001) was negatively associated with global PSQI scores. Multivariate logistic regression analyses showed that menopause (odds ratio, 1.453; 95% CI, 1.030 to 2.051; P < 0.05), long sleep duration (odds ratio, 0.545; 95% CI, 0.418 to 0.710; P < 0.001), and snoring (odds ratio, 2.022; 95% CI, 1.312 to 3.116; P = 0.001) were independent predictors of poor sleepers.

CONCLUSIONS

Postmenopausal women without vasomotor symptoms have significantly higher global PSQI scores and a higher risk of being poor sleepers than premenopausal women. In addition, menopause and snoring are associated with an increased risk of poor self-reported sleep quality independently of cardiometabolic factors and lifestyle, whereas long sleep duration is associated with a decreased risk of poor self-reported sleep quality.

2,3-Oxidosqualene cyclase protects liver cells from the injury of intermittent hypoxia by regulating lipid metabolism

PURPOSE

2,3-Oxidosqualene cyclase (OSC), an important enzyme of cholesterol biosynthesis, catalyzes the highly selective cyclization of 2,3-monoepoxysqualene to lanosterol. Intermittent hypoxia (IH) is a hallmark feature in obstructive sleep apnea (OSA) which is increasingly recognized as an independent risk factor for liver injury. The aim of this study was to determine the effect of IH on OSC expression and evaluate the role of OSC in the IH-induced apoptosis in hepatic cell line human liver cell (HL-02).

METHODS

HL-02 cells were exposed to normoxia or IH. Cell Counting Kit-8 (CCK-8) assay was used to value cell proliferation, and flow cytometry was used to determine cell apoptosis. The expression of OSC messenger RNA (mRNA) was evaluated by quantitative real-time PCR, and the expression of OSC protein was determined by Western blot. To further investigate the function of OSC in IH-induced apoptosis, oxidosqualene cyclase-enhanced green fluorescence protein (OSC-EGFP) plasmid was constructed to over-express OSC protein. Triglyceride content in HL-02 cells was analyzed by oil red staining or Triglyceride Quantification Kit.

RESULTS

We found that IH inhibited HL-02 cell proliferation and accelerated cell apoptosis. IH decreased OSC expression, and over-expression of OSC could protect HL-02 cells against the IH-induced hepatic cell injury. Moreover, over-expression of OSC could attenuate IH-induced cellular triglyceride accumulation.

CONCLUSIONS

These findings suggest that OSC are involved in IH-induced hepatic cell injury. These results may contribute to the further understanding of the mechanism underlying the liver injury in OSA patients.

The impact of obstructive sleep apnea on high-sensitivity C-reactive protein in subjects with or without metabolic syndrome

BACKGROUND

It is unclear whether obstructive sleep apnea (OSA) is independently associated with increased levels of the acute-phase reactant C-reactive protein (CRP). The purpose of this study was to evaluate the relationship between OSA and high-sensitivity CRP (hs-CRP) levels according to the presence or absence of metabolic syndrome (MetS).

METHODS

This study recruited 245 male bus drivers from one transportation company in Taiwan. Each participant was evaluated by a polysomnography (PSG) test, blood lipids examination, and hs-CRP. Severity of OSA was categorized according to the apnea-hypopnea index (AHI).

RESULTS

Subjects were categorized into severe OSA group (n = 44; 17.9 %), moderate and mild OSA group (n = 117; 47.8 %), and non-OSA group (n = 84; 34.3 %). AHI had a significant association with hs-CRP (β = 0.125, p = 0.009) adjusting for age, smoking, drinking, and MetS status. Hs-CRP was elevated with severe OSA (β = 0.533, p = 0.005) even adjusting for BMI and MetS. Moreover, there was an independent effect for adjusted odds ratios (AORs) between the stratification of the severity for OSA and MetS.

CONCLUSION

Elevated hs-CRP level is associated with severe OSA, independent of known confounders. The effect of OSA in CRP is independent of MetS was identified.