[Cardiovascular morbidity associated with obstructive sleep apnea syndrome]

Potential Diagnostic and Monitoring Biomarkers of Obstructive Sleep Apnea-Umbrella Review of Meta-Analyses

Obstructive sleep apnea (OSA) is a prevalent, underdiagnosed disease that imposes a significant impact on the health and wellbeing of patients and a financial burden on individuals, their families, and society. Development of new methods of testing other than an overnight sleep study, such as measurement of serum or plasma biomarkers, may provide an easier diagnostic process to identify patients with OSA and allow earlier initiation of treatment, which might prevent serious comorbidities. We conducted a systematic review and quality assessment of available meta-analyses regarding potential diagnostic and monitoring biomarkers of obstructive sleep apnea. A total of 14 sets of candidate biomarkers displayed differences in levels or concentrations in OSA patients compared to non-OSA controls, and decreased after OSA treatment: CRP, IL-6, TNF-α, Il-8, HCY, ICAM-1, VCAM-1, VEGF, TC, LDLc, HDLc, TG, leptin, MDA, ALT, AST, IGF-1, adiponectin, and cortisol. This review summarizes the evidence for OSA-associated potential biomarkers and demonstrates that the quality of available studies, as measured by AMSTAR2, is often low and associated with a high risk of bias.

The Association of Oxidative Stress in the Uvular Mucosa with Obstructive Sleep Apnea Syndrome: A Clinical Study

The hypothesis that individuals with obstructive sleep apnea syndrome (OSAS) demonstrate oxidative stress in the uvular mucosa that correlates with OSAS occurrence was investigated. A total of 128 participants (mean age 45.8, mean body mass index 30.7, female–male ratio 1:20) were divided into the non-OSAS group (apnea–hypopnea index—AHI < 5) and OSAS-group (AHI ≥ 5), in which mild (5 ≤ AHI < 15), moderate (15 ≤ AHI < 30), and severe (AHI ≥ 30) sub-groups were distinguished. Laryngological examination, Epworth Sleep Scale questionnaire, and home sleep study were performed to obtain AHI, mean oxygen saturation, and lowest oxygen saturation. Total oxidative status (TOS) and total antioxidative status (TAS) were assayed in the uvular mucosa taken during palatoplasty or palatopharyngoplasty. The severity of oxidative stress was expressed as oxidative stress index (OSI). Oxidative/reductive imbalance was noted in the mucosa of the uvula of OSAS individuals, and TAS of the uvular mucosa negatively correlated with the severity of this syndrome. TOS and OSI in the mild, moderate, and severe OSAS were higher than in the non-OSAS group, whereas TAS of the uvular mucosa in the OSAS group was lower compared to the non-OSAS group. In conclusion, oxidative stress in the uvular mucosa is associated with the occurrence of OSAS.

Alterations in Parafoveal and Optic Disc Vessel Densities in Patients with Obstructive Sleep Apnea Syndrome

Purpose

To analyze the effects of obstructive sleep apnea syndrome (OSAS) on ocular parameters and determine the alterations in macular vasculature by optical coherence tomography-angiography (OCT-A) in patients with different stages of OSAS.

Methods

All the participants underwent a full ophthalmological examination. Using the macular OCT-A scans, the retinal peripapillary capillary plexus (RPCP), foveal avascular zone (FAZ), and superficial and deep vessel densities were recorded.

Results

A total of 77 patients (154 eyes) with OSAS and 27 control cases (54 eyes) were included in this prospective study. Of the OSAS patients, 27 had mild, 24 had moderate, and 26 had severe disease. The intraocular pressure (IOP) values were significantly higher in the severe OSAS group than the control cases (p = 0.001). The average retinal nerve fiber layer (RNFL) thickness and the RNFL thickness of the temporal and inferior quadrants were significantly lower in the severe OSAS group compared with the control cases (p = 0.001). The average retinal nerve fiber layer (RNFL) thickness and the RNFL thickness of the temporal and inferior quadrants were significantly lower in the severe OSAS group compared with the control cases (p = 0.001). The average retinal nerve fiber layer (RNFL) thickness and the RNFL thickness of the temporal and inferior quadrants were significantly lower in the severe OSAS group compared with the control cases (

Conclusions

Decreased vascular structures and increased FAZ may also be associated with the disease severity in OSAS and may be the main pathophysiological mechanisms in ocular alterations, which should be investigated in further studies.

Can Hypoxic Conditioning Improve Bone Metabolism? A Systematic Review

Among other functions, hypoxia-inducible factor plays a critical role in bone–vascular coupling and bone formation. Studies have suggested that hypoxic conditioning could be a potential nonpharmacological strategy for treating skeletal diseases. However, there is no clear consensus regarding the bone metabolism response to hypoxia. Therefore, this review aims to examine the impact of different modes of hypoxia conditioning on bone metabolism. The PubMed and Web of Science databases were searched for experimental studies written in English that investigated the effects of modification of ambient oxygen on bone remodelling parameters of healthy organisms. Thirty-nine studies analysed the effect of sustained or cyclic hypoxia exposure on genetic and protein expression and mineralisation capacity of different cell models; three studies carried out in animal models implemented sustained or cyclic hypoxia; ten studies examined the effect of sustained, intermittent or cyclic hypoxia on bone health and hormonal responses in humans. Different modes of hypoxic conditioning may have different impacts on bone metabolism both in vivo and in vitro. Additional research is necessary to establish the optimal cyclical dose of oxygen concentration and exposure time.

Cardiotrophin-1 and leptin as cardiovascular risk markers in male patients with obstructive sleep apnea syndrome

Introduction

Elevated cardiotrophin-1 (CT-1) and leptin levels are important risk factors for cardiovascular diseases (CVDs). Obstructive sleep apnea syndrome (OSAS) has also been reported to increase this risk. The aim of this study is to evaluate serum concentrations of CT-1 and leptin in patients with OSAS and whether there is a possible association between CT-1, leptin and OSAS severity.

Material and methods

Fifty newly diagnosed OSAS patients and thirty nonapneic snoring subjects participated in this study. Fasting serum lipid profile markers were evaluated. The measurements of serum CT-1 and leptin levels were carried out using human ELISA kits.

Results

Significant differences were found in the serum CT-1 and leptin levels between the two groups. Serum median CT-1 levels in patient and control groups, respectively, were 19.47; 8.23 pg/ml and leptin levels were 2.07; 1.29 ng/ml (p < 0.001). In the severe patient group, serum median CT-1 level was statistically significantly higher than the median level in the mild/moderate group. There was no correlation between patients’ leptin and lipid profile parameters and CT-1 concentrations were not associated with triglyceride, cholesterol or LDL cholesterol levels except HDL cholesterol: CT-1 levels were positively correlated with HDL levels (p = 0.02).

Conclusions

Both CT-1 and leptin were significantly elevated in the patient group. Furthermore, CT-1 and leptin were associated with OSAS and CT-1 was associated with the disease severity.

Perioperative safety and complications in treatment of oral and maxillofacial surgery patients under general anesthesia with obstructive sleeping disorders

Patients with sleeping disorders, such as obstructive sleep apnea, (OSA) have a higher risk for postoperative complications after maxillofacial surgery under general anesthesia. The aim of this study was to detect specific complications after oral and maxillofacial surgery. Sixty-nine cases of patients with middle or severe sleep apnea who underwent an operation under general anesthesia in the oral and maxillofacial region were retrospectively analyzed. This group was compared with an age and diagnosis matched group without sleep apnea receiving the same operative treatment. We found a significant difference between the two groups concerning body mass index, the ASA-Index, the Cormack-Mallampati Index, the number of pre-existing conditions, and home medication (p < 0.05). Concerning the length of stay, overrun of estimated mean length of stay, and number of surgical complications and hypertonic events, no difference could be detected. Almost 28% of the patients with OSA in our study suffered a substantial respiratory complication even under intensive care observation. The number of patients with oxygen desaturation was 9% in the control group, which differed significantly (p = 0.0093) from the number of such patients in the OSA group. In this study, we have shown that the presence of OSA in patients undergoing elective maxillofacial surgery is associated with a considerable number of comorbidities in the postoperative period. Through preoperative OSA screening and OSA evaluation, an improvement in management of surveillance resources could be achieved and the OSA-specific risk could be assessed more precisely and also reduced.

Arterial stiffness alteration and obstructive sleep apnea in an elderly cohort free of cardiovascular event history: the PROOF cohort study

INTRODUCTION

Several studies suggest in middle-aged subjects a relationship between arterial stiffness, a cardiovascular risk marker, and moderate to severe obstructive sleep apnea (OSA). No extensive data are present in older subjects. This study explores this association in a sample of healthy older subjects suffering OSA.

METHODS

A total of 101 volunteers aged 75.3 ± 0.7 years were examined at the hospital sleep center. Each subject was assessed for medical history, body mass index and 24-h blood pressure measures, biological blood samples, and home polygraphy in 2002-2003 (P2) as well as in 2009-2010 (P4). Arterial stiffness was also assessed using carotid-femoral and carotid-radial pulse wave velocity (cfPWV and crPWV) during P4 examination.

RESULTS

The total group consisted of 59 women and 42 men with a mean apnea-hypopnea index (AHI) of 17.8 ± 12.1 and a mean oxygen desaturation index (ODI) of 9.8 ± 8.9. No-OSA (AHI < 15) represented 50% of the sample, and severe cases (AHI > 30) 17%. No significant differences had been founded between men and women for blood pressure, cfPWV, and crPWV. Considering the severity of the AHI, no significant differences between groups were present for PWV and blood pressure values. No difference for PWV was present for subjects with and without hypertension. No correlation was found between PWV value and AHI and ODI values at P2 or between P2 and P4 visits. cfPWV was higher in patients demonstrating incident hypertension during the follow-up.

CONCLUSIONS

In this sample of older subjects, PWV is not affected by AHI and ODI but was associated with incident hypertension. These results may suggest potential protective and adaptive mechanisms in older sleep apnea patients.

CLINICAL TRIAL REGISTRATIONS

NCT 00759304 and NCT 00766584 .

Impact of an oral appliance on obstructive sleep apnea severity, quality of life, and biomarkers

OBJECTIVE/HYPOTHESIS

To investigate outcomes including efficacy, quality of life, and levels of inflammatory markers of a mandibular advancement device (MAD) for moderate-to-severe obstructive sleep apnea (OSA).

STUDY DESIGN

Case-control study.

METHODS

Patients with apnea-hypopnea index (AHI) ≥ 15/hr who only accepted MAD therapy (study group) or who refused any treatment (control group) were recruited. At baseline and at 6 months, polysomnography, Epworth Sleepiness Scale (ESS), Functional Outcomes of Sleep Questionnaire (FOSQ), C-reactive protein (CRP), interleukin 1β, interleukin 6, and tumor necrosis factor α (TNF-α) were assessed in both groups.

RESULTS

At baseline, the study group (n = 30) showed a higher percentage of rapid eye movement sleep and higher CRP levels (P < .05) than the control group (n = 10). At 6 months, the MAD significantly improved AHI and lowest oxygen saturation (P < .01), non-rapid eye movement (N)1 and N3 sleep stages (P < .05), ESS score (P < .05), FOSQ total score (P < .01), interleukin 1β (P < .05), and TNF-α (P < .01) compared with the untreated group. In the overall, moderate, and severe OSA groups, 63.3%, 75%, and 50%, respectively, achieved at least good response.

CONCLUSIONS

Use of a MAD significantly improved polysomnographic parameters, quality of life, and some inflammatory markers (CRP, IL-β, and TNF-α) in a significant proportion of patients with moderate OSA and in some patients with severe OSA. Hence, a MAD may be a viable alternative therapy in patients with moderate-to-severe OSA who refuse continuous positive airway pressure.

LEVEL OF EVIDENCE

3b. Laryngoscope, 128:1720-1726, 2018.

Obstructive sleep apnea and hormones - a novel insight

Obstructive sleep apnea (OSA), a disorder characterized by repetitive collapse of the upper respiratory tract during sleep, occurs in about 4% of middle-aged men and 2% of women. The incidence of the disorder is rising due to an increase in obesity and ageing of the population. Patients with obstructive sleep apnea are at elevated risk of some endocrinal and metabolic disorders, which may lead to serious consequences including shortening of life expectancy. The recognition and understanding of interactions between local upper airway dysfunction and its endocrinal consequences is therefore vital. In this review we will focus on the influence of OSA on bone metabolism and endocrine homeostasis.

Snoring and components of metabolic syndrome in Southeastern Chinese adults: A community-based study

INTRODUCTION

Snoring has been associated with a number of abnormal conditions, but little work has been done on its association with components of metabolic syndrome based on the epidemiology in Chinese adults.

OBJECTIVE

This study aimed to investigate the association between snoring and components of metabolic syndrome in southeastern Chinese adults.

METHODS

A two-stage, cross-sectional community-based study was performed in Fuzhou, Southeast China, from 2005 to 2009. Stage 1: 5500 subjects were administered a questionnaire. Data on self-reported snoring status, daytime somnolence, demographic data, disease histories, and potential confounders were collected and anthropometric measurements were performed. Stage 2: 1000 subjects who were already investigated underwent a blood test and measurement of blood pressure.

RESULTS

Data from 4286 subjects were available; 606 subjects were habitual snorers. The prevalence of overweight or obesity, hyperglycemia, hypertension, and dyslipidemia in occasional and habitual snorers was higher than that in the study population (16.66%, 7.89%, 10.52%, and 5.81%, respectively). A significantly increasing trend based on snoring frequency existed in the prevalence of metabolic disorders. The prevalence of components of metabolic syndrome continued to be significantly associated with snoring frequency after controlling confounding factors. Odds ratios of suffering from the aforementioned conditions for occasional and habitual snorers were 1.5-2.5 (P < 0.05) and 2.4-4.8 (P < 0.001) times higher, respectively, compared with nonsnorers.

CONCLUSIONS

The prevalence of snoring and components of metabolic syndrome is high in southeastern Chinese adults. Both habitual and occasional snoring are closely associated with metabolic disorders independent of confounding factors.

Bone mineral density and changes in bone metabolism in patients with obstructive sleep apnea syndrome

The aim of this study was to evaluate the differences between patients with obstructive sleep apnea syndrome (OSAS) and phenotypically similar subjects without OSAS in terms of bone mineral density (BMD) and bone turnover markers. The study was conducted on 30 males diagnosed with OSAS and 20 healthy males. All subjects underwent polysomnographic testing. Calcium, phosphorus parathyroid hormone, thyroid stimulating hormone, bone-specific alkaline phosphatase, 25-hydroxyvitamin D3, osteocalcin, and beta-CrossLaps (β-CTx) were measured. BMD in the lumbar spine (L1-L4) and femoral neck was measured by dual energy X-ray absorptiometry. There was no statistically significant difference between the two groups in terms of demographic data with the exception of bone mass index and waist circumference. (p < 0.05). Analyses showed significantly lower BMD measurements in the femoral neck and T-scores in the femoral neck in patients diagnosed with OSAS. Serum β-CTx levels were found to be statistically significantly higher in the OSAS group (p = 0.017). In multivariate assessments performed for apnea/hypopnea index values, mean saturation O2 levels were found to be significantly associated with osteocalcin levels and neck BMD. OSAS patients might represent a risk group with respect to loss of BMD and bone resorption. It is important to evaluate bone loss in these patients. Further studies should be carried out on larger study populations to evaluate the effects of chronic hypoxia on BMD in detail.

Association between self-reported snoring and arterial stiffness: data from the Brisighella Heart Study

The correlation of both obstructive sleep apnoea syndrome (OSAS) and snoring with cardiovascular risk is well known, but its investigation is complex and not suitable for studying large cohorts of subjects. Thus, we prospectively evaluated 1476 non-pharmacologically treated subjects selected from the last survey of the Brisighella Heart Study. Snoring and sleep apnoea were investigated asking the subjects if they were aware of snoring during the night, and if this was associated with episodes of apnoea. A full set of clinical and laboratory parameters were evaluated, while augmentation index (AIx), and pulse wave velocity (PWV) were recorded with the Vicorder(®) apparatus. A logistic regression analysis identifies as main independent predictors of AIx age (OR 1.058, 95% CI 1.043-1.065, p < 0.001), Body Mass Index (OR 1.046, 95% CI 1.014-1.079, p = 0.005), and apolipoprotein B (OR 1.014, 95% CI 1.004-1.023, p = 0.001). The main independent predictors of PWV are snoring (OR 1.215, 95% CI 1.083-1.390, p < 0.001), and snoring with apnoea (OR 1.351, 95% CI 1.135-1.598, p = 0.014), age (OR 1.078, 95% CI 1.052-1.089, p < 0.001), serum uric acid [SUA] (OR 1.093, 95% CI 1.026-1.151, p < 0.001) and mean arterial pressure (OR 1.042, 95% CI 1.024-1.056, p < 0.001). In conclusion, in our cohort of overall healthy subjects, self-reported snoring and sleep apnoea are independently associated with a higher PVW, and AIx is statistically significantly higher in snorers with or without sleep apnoea than in non-snorers. Body Mass Index and apolipoprotein B are associated with AIx, while SUA and mean arterial pressure are related to PWV.

The perception of Obstructive Sleep Apnoea/Hypopnoea Syndrome (OSAHS) among Italian general practitioners

BACKGROUND

Obstructive Sleep Apnoea/Hypopnoea Syndrome (OSAHS) is a common disorder in the general population but often underestimated and underdiagnosed.

METHODS

This questionnaire-based study evaluated the overall level of knowledge about OSAHS among Italian General Practitioners (GPs), who are frequently involved in the management of this complex disease. This represents an interesting aspect, because GPs intercept many of the patients with OSAHS, in which C-PAP could be potentially indicated. Randomly-selected GPs were provided with questionnaires, which were then returned anonymously.

RESULTS

80 questionnaires have been validated; the participants in the sample examined were represented by 43 females and 37 males; the average age of participants was 51 years. The general knowledge on OSAHS is overall satisfactory among GPs; it is recognized by most of the GPs interviewed as pathology in constant increase, and associated with predisposing factors such as obesity. High blood pressure is perceived as an independent cardiovascular risk factor in patients with OSAHS, in line with the majority of international studies. The C-PAP has been identified as the care gold standard in patients with OSAHS, despite the lack of patient compliance in relation to this procedure, while polysomnography was found to be the main instrumental procedure used in the diagnostic workup of OSAS. The pulmonologist and a multidisciplinary team have been identified as the specialist figures of reference to which to direct the patient through the diagnostic workup. Respiratory therapists and nurses represent the role of educator in the proper management of the C-PAP in the opinion of 62% of respondents, while only 34% think that this role should be played by the GPs and/or other specialists.

CONCLUSIONS

In conclusion, this survey about the perception of OSAHS among GPs in Italy highlighted a satisfactory overall knowledge of OSAHS and only few weak points.