Changes in Plasma Angiotensin II and Circadian Rhythm of Blood Pressure in Hypertensive Patients with Sleep Apnea Syndrome Before and After Treatment

Objective To explore the changes in plasma angiotensin II （Ang Ⅱ） and circadian rhythm of blood pressure among hypertensive patients with sleep apnea syndrome （SAS） before and after continuous positive airway pressure （CPAP） or surgical treatment. Methods A total of 180 essential hypertension patients were enrolled in our study. The determination of plasma Ang Ⅱ concentration, ambulatory blood pressure （ABP）, and polysomnography （PSG） monitoring were performed before and 3 months after CPAP or surgical treatment. Results Patients were classified into three groups by their apnea-hypopnea index （AHI）： essential hypertension group （EH group, n=72; AHI〈5）, essential hypertension with mild SAS group （EH＋mild SAS group, n=60, 5≤AHI〈20）, and essential hypertension with moderate and severe SAS group （EH＋moderate-severe SAS group, n=48, AHI_〉20）. The concentrations of plasma AngⅡ in the above three groups were 13.42±3.27, 16.17±3.82, and 18.73±4.05 ng/mL respectively before treatment, and AngⅡ concentration in EH patients combined with SAS was significantly higher than that in EH group （all P〈0.05）. After treatment the values in the latter two groups significantly decreased to 14.67±2.56 and 15.03±3.41 ng/mL respectively （P〈0.05）. The incidence of non-dipper blood pressure curve in EH patients was 31.9%, and those in hypertensive patients with mild SAS and moderate-severe SAS were 51.7% and 58.3%, respectively before treatment. The incidence of non-dipper blood pressure curve in the EH patients with mild SAS was significantly higher than that of patients with EH alone （P〈0.05）. After CPAP treatment or surgery, the incidence of non-dipper blood pressure curve in the two SAS groups was significantly decreased to 38.3% and 39.6%, respectively （P〈0.05）. Conclusions Ang Ⅱ might play a role in blood pressure variability in patients with obstructive SAS. CPAP or surgical treatment can improve blood pressure disorder and decrease plasma Ang Ⅱ level in patients with obstructive SAS.

Continuous positive airway pressure to improve insulin resistance and glucose homeostasis in sleep apnea

Obstructive sleep apnea syndrome(OSAS)is a relatively common disorder in the adult population.It is associated with alterations in glucose metabolism and increases the risk for diabetes mellitus.Continuous positive airway pressure(CPAP)is the treatment of choice for OSAS.It may also have a favorable effect on insulin resistance and glucose metabolism,although relevant data is conflicting.Additional research is still needed to fully establish the effect of CPAP on glucose homeostasis.It should ascertain which patients may benefit most and how long treatment takes to induce favorable changes.Finally,patient compliance is being appreciated as a major factor influencing therapeutic outcomes,and this needs to be further examined.

Clinical observation of soft palate-pharyngoplasty in the treatment of obstructive sleep apnea hypopnea syndrome in children

BACKGROUND Childhood obstructive sleep apnea hypopnea syndrome(OSAHS)is a common clinical disease that can cause serious complications if not treated in time.The preferred treatment for OSAHS in children is surgery.AIM To observe the effects of soft palate-pharyngoplasty on postoperative outcome,pharyngeal formation,and possible complications.METHODS A total of 150 children with snoring,hernia,and mouth breathing were selected.A polysomnography test was performed to confirm the diagnosis of OSAHS.The children were randomly divided into experimental and control groups.The experimental group underwent adenoidectomy,tonsillectomy,and soft palatepharyngoplasty.The control group underwent adenoidectomy and tonsillectomy.The t-test and chi-square test were used to compare conditions such as postoperative fever,postoperative hemorrhage,and pharyngeal reflux.Postoperative efficacy and complications were interrogated and observed in the form of outpatient follow-up and telephone follow-up at 6 mo and 1 year after surgery.The curative effects were divided into two groups:Cure(snoring,snoring symptoms disappeared)and non-cure.RESULTS The effective rate of the experimental group was significantly higher than that of the control group,but the difference was not statistically significant(P>0.05).The incidence of postoperative bleeding was lower in the experimental group.There was no postoperative pharyngeal reflux in either group.In the experimental group,the incidence of hyperthermia(body temperature exceeded 38.5°C)was lower than that in the control group.The difference in postoperative swallowing pain scores between the experimental and control groups was significant.CONCLUSION Soft palate-pharyngoplasty can more effectively enlarge the anteroposterior diameter and transverse diameter of the isthmus faucium.Compared with surgery alone,it can better treat OSAHS in children,improve the curative effect,reduce the risk of perioperative bleeding,close the surgical cavity,reduce the risk of postoperative infection,reduce the proportion of postoperative fever,and accelerate healing.Although this process takes more time,it is simple,safe,and effective.

Stem/progenitor cells and obstructive sleep apnea syndrome - new insights for clinical applications

Obstructive sleep apnea syndrome(OSAS) is a widespread disorder, characterized by recurrent upper airway obstruction during sleep, mostly as a result of complete or partial pharyngeal obstruction. Due to the occurrence of frequent and regular hypoxic events, patients with OSAS are at increased risk of cardiovascular disease, stroke, metabolic disorders, occupational errors, motor vehicle accidents and even death. Thus, OSAS has severe consequences and represents a significant economic burden. However, some of the consequences, as well as their costs can be reduced with appropriate detection and treatment. In this context, the recent advances that were made in stem cell biology knowledge and stem cell- based technologies hold a great promise for various medical conditions, including respiratory diseases. However, the investigation of the role of stem cells in OSAS is still recent and rather limited, requiring further studies, both in animal models and humans. The goal of this review is to summarize the current state of knowledge regarding both lung resident as well as circulating stem/progenitor cells and discuss existing controversies in the field in order to identify future research directions for clinical applications in OSAS. Also, the paper highlights the requisite for inter-institutional, multi-disciplinary research collaborations in order to achieve breakthrough results in the field.

Management of non-alcoholic fatty liver disease patients with sleep apnea syndrome

Nonalcoholic fatty liver disease(NAFLD)is strongly associated with sleep apnea syndrome(SAS).Many NAFLD patients have SAS,and obstructive sleep apnea hypopnea syndrome is also considered to be an independent risk factor for NAFLD,as it contributes to the progression of NAFLD via oxidative stress,lipid peroxidation,inflammation,and insulin resistance.This review aims to provide some recommendations for the management of NAFLD patients with SAS,including diet,exercise,weight loss,and continuous positive airway pressure.This review also highlights the importance of effective strategies in NAFLD prevention and treatment.

Obstructive Sleep Apnea Syndrome Implications on Health and Adherence to CPAP Treatment

Respiratory disorders during sleep have as a general characteristic the alteration of the respiratory cycle while sleeping. The most outstanding characteristic of Obstructive Sleep Apnea Syndrome (OSA) is the partial (hypopnea) or total (apnea) obstruction of the upper airway that occurs repeatedly during sleep. The OSA is global public health issue. When it is not treated, OSA represents a cost two or three times higher of the institutional resources for health. Studies conducted in different countries indicate that the prevalence of the OSA goes from 2% to 10% in general population. The OSA is a serious sleep disorder that has negative implications on multiple systems of the organism. It is associated with hypertension, diabetes and the metabolic syndrome. When OSA coexists with a heart disease or ischemic heart disease, it significantly raises the probability of a heart failure. The use of Continuous Positive Airway Pressure (CPAP) is so far the most effective method for OSA treatment. Intervention at different levels (physiological, educational and psychological intervention) appears to be important in adherence to CPAP treatment.

A Very Severe Obstructive Sleep Apnea Syndrome: In a Cause of Resistant Hypertension with One Sample Case

When blood pressure values remain above the target in a hypertensive patient treated concomitantly with three anti-hypertensive drugs including a diuretic, maximum well-tolerated doses, this is a resistant arterial hypertension. In this case, it is advisable to look for a secondary cause such as a drug intake that influencing the blood pressure or the presence of obstructive sleeping syndrome (OSAS). We report a clinical case of a patient with a high cardiovascular risk at the age of 50, hypertensive and diabetic, with dyslipidemia and obesity. He was on anti-hypertensive triple therapy at an optimal dose. Her diabetes was balanced with 6.4% glycated hemoglobin. Dyslipidemia has being treated. Despite healthy diet including a low sodium diet and weight loss, blood pres- sure target was not reached. With self-measurement, the mean arterial pressure was 180/110 mmHg and on ABPM it was 167/113 mmHg. The ventilatory polygraphy finds a severe OSA with an IAH = 56.6. Treatment with PCP (Con- tinuous positive pressure) allowed this patient to control blood pressure. The search for OSA should be systematic in face of resistant hypertension, in par- ticular in overweight or obese patients.

Obstructive Sleep Apnea Syndrome Phenotyping by Cluster Analysis: Typical Sleepy, Obese Middle-aged Men with Desaturating Events are A Minority of Patients in A Multi-ethnic Cohort of 33% Women

Objective Several clinical obstructive sleep apnea syndrome(OSAS)phenotypes associated with heterogeneous cardiovascular risk profiles have been recently identified.The purpose of this study was to identify clusters amongst these profiles that allow for the differentiation of patients.Methods This retrospective study included all moderate-to-severe OSAS patients referred to the sleep unit over a 5-year period.Demographic,symptom,comorbidity,polysomnographic,and continuous positive airway pressure(CPAP)adherence data were collected.Statistical analyses were performed to identify clusters of patients.Results A total of 567 patients were included(67%men,54±13 years,body mass index:32±7 kg/m2,65%Caucasian,32%European African).Five clusters were identified:less severe OSAS(n=172);healthier severe OSAS(n=160);poorly sleeping OSAS patients with cardiometabolic comorbidities(n=87);younger obese men with sleepiness at the wheel(n=94);sleepy obese men with very severe desaturating OSAS and cardiometabolic comorbidities(n=54).Patients in clusters 3 and 5 were older than those in clusters 2 and 4(P=0.034).Patients in clusters 4 and 5 were significantly more obese than those in the other clusters(P=0.04).No significant differences were detected in terms of symptoms and comorbidities.Polysomnographic profiles were very discriminating between clusters.CPAP adherence was similar in all clusters but,among adherent patients,daily usage was more important in cluster 1(less severe patients)than in cluster 5.Conclusion This study highlights that the typical sleepy obese middle-aged men with desaturating events represent only a minority of patients in our multi-ethnic moderate-to-severe OSAS cohort of 33%females.

Factors Associated with Excessive Daytime Sleepiness in Obstructive Sleep Apnea Syndrome under CPAP Treatment

The purpose of this study was to assess factors associated with subjective sleep evaluation, chiefly excessive daytime sleepiness (EDS) in obstructive sleep apnea syndrome (OSAS) adult outpatients under continuous positive airway pressure (CPAP) treatment. One thousand and forty-eight OSAS outpatients (mean age: 51.4% male: 90.5%) who were treated by CPAP were consecutively collected. Age, sex, CPAP compliance (CPAP usage as their device of nights with application-time of at least 4 hours per night objectively;%usage ≥ 4 h/d), and Japanese version of the Pittsburgh Sleep Quality Index (PSQI-J) of the patients showing EDS (Japanese version of the Epworth Sleepiness Scale;JESS ≥ 11) were compared cross-sectionally with those of the patients who did not show EDS (JESS < 11). Nineteen point two % of all patients showed EDS subjectively. Two hundred one patients were classified to an EDS(+) group and an 847 patients were classified to EDS(–) group. Age and global PSQI-J scores were significantly different between the two groups. Logistic regression showed that EDS was significantly associated with global PSQI-J scores, but not with age. Among PSQI-J components, overall sleep quality, duration of sleep, sleep disturbance, and day dysfunction due to sleepiness were significantly higher in the EDS(+) group. Especially, 19.4% of patient in the EDS(+) group reported actual sleep time during the past month to be less than 5 hours/day. Although functional relationship should be further evaluated, insufficient sleep is the main factor associated with EDS in the OSAS patients under CPAP treatment.

Relationship between metabolic syndrome and hypercapnia among obese patients with sleep apnea Relationship between metabolic syndrome and hypercapnia among obese patients with sleep apnea

BACKGROUND In the obese patient population,some patients have severe obstructive sleep apnea(OSA)with daytime hypoventilation.Such patients are generally identified on the basis of the presence or absence of daytime hypercapnia,and the condition is called obesity hypoventilation syndrome.However,mechanisms for such daytime hypoventilation remain unclear.AIM To investigate metabolic syndrome and daytime hypercapnia association based on hypercapnia prevalence in obese OSA patients in a nested case-control study.METHODS Consecutive obese patients(body mass index≥30 kg/m2)who underwent polysomnography due to suspected OSA were included.Among them,patients with severe OSA(apnea hypopnea index≥30/h)were divided into two groups according to the presence or absence of hypercapnia during wakefulness(arterial partial pressure of carbon dioxide≥or<45 Torr,respectively).The characteristics and clinical features of these two groups were compared.RESULTS Among 97 eligible patients,25 patients(25.8%)had daytime hypercapnia.There were no significant differences in age,gender,body mass index,apnea-hypopnea index,and Epworth Sleepiness Scale scores between the two groups.However,patients with hypercapnia had a significantly lower arterial partial pressure of oxygen level(75.8±8.2 torr vs 79.9±8.7 torr,P=0.042)and higher arterial partial pressure of carbon dioxide level(46.6±2.5 torr vs 41.0±2.9 torr,P<0.001).Additionally,patients with hypercapnia were more likely to have metabolic syndrome(72.0%vs 48.6%,P=0.043)and a higher metabolic score(the number of satisfied criteria of metabolic syndrome).In multivariate logistic regression analysis,the presence of metabolic syndrome was associated with the presence of hypercapnia(OR=2.85,95%CI:1.04-7.84,P=0.042).CONCLUSION Among obese patients with severe OSA,26%of patients had hypercapnia during wakefulness.The presence of metabolic syndrome was independently correlated with the presence of daytime hypercapnia.

Hypertension and obstructive sleep apnea in Caucasian children

AIM:To evaluate the prevalence of hypertension and/or left ventricular hypertrophy(LVH) in children with a diagnosis of obstructive sleep apnea(OSA).METHODS:A cross-sectional case series of consecutive,otherwise healthy children aged > 4 years,with polysomnography-proven OSA [apnea hypopnea index(AHI) > 1.5/h] is described.Echocardiography was performed on all subjects and left ventricular mass was calculated.Study subjects underwent additional investigation with 24-h ambulatory blood pressure(BP) monitoring.RESULTS:Thirty children(21 males) were studied.Mean age was 8.9 years.Mean body mass index was 19.87 kg/cm2.Mean AHI was 14.3/h.10/30(33%) of the study population met criteria for pre-hypertension(n = 3) or masked hypertension(n = 7) based on standard ambulatory monitoring criteria.All 10 children had systolic hypertension throughout the night with 5 of these also having elevated daytime systolic readings.There was a relationship between AHI and BP showing an increase of 1.162 percentile units in mean diastolic night BP(age,gender and height specific) per unit increase in AHI(P = 0.018).There were no subjects with LVH and/or right ventricular hypertrophy.CONCLUSION:In our population of otherwise healthy Caucasian children,there was a high prevalence of hypertension that would not have been identified using standard office/clinic protocols.

Does Positive Airway Pressure Therapy Result in Improved Sleep Quality?

Introduction: Positive airway pressure (PAP) therapy is the gold-standard for obstructive sleep apnea (OSA) management. While it is known that PAP is efficacious for controlling breathing events during sleep when it is worn at the right pressure for the amount of time prescribed, there is less clear data on how well it improves sleep quality. There are few studies that have examined the effectiveness of PAP therapy on sleep quality. Methods: OSA participants (n = 241) from a larger trial examining a PAP adherence were included. Participants were provided with PAP instruction and followed at 2 months and 4 months. PAP adherence was measured as the number of hours per night at prescribed pressure, an objective measure of treatment adherence. The Pittsburgh Sleep Quality Index (PSQI) was used as the primary measure of sleep quality. Results: The PSQI was significantly correlated with PAP adherence at both the 2-month and 4-month time points, such that lower sleep quality was associated with lower PAP use. This finding held for the sleep disturbance subscale of the PSQI. Over 55% of those using PAP therapy at the 4-month time point continued to report significantly disturbed sleep. Discussion: This study shows that PAP therapy does not appear to improve sleep quality to a degree that would be expected. Over half of those patients using PAP therapy still experienced disturbed sleep. Whether the disturbed sleep is directly attributable to the PAP device itself or to disturbed sleep secondary to uncontrolled OSA when PAP is not worn is worthy of further investigation.

Obesity and obstructive sleep apnea, bariatric surgery and follow-up post treatment

Bariatric surgery is a valid treatment alternative for obese patients with obstructive sleep apnea (OSA), but subjects who are overweight or obese represent a poor model to investigate the role of OSA treatment on cardiovascular variables, calling into question the attribution of cardiovascular and metabolic problems associated with OSA with excess weight. Seventeen patients with significant obesity who demonstrated OSA with a high apnea-hypopnea index (AHI) were treated with bariatric surgery alone after refusal of nasal continuous positive airway pressure (CPAP) treatment. At approximately 3 years post-surgery, subjects demonstrated a significant drop in blood pressure measured at rest, improvement in sleepiness and fatigue visual analogue scales, but continued to complain of daytime sleepiness. Polysomnography in these subjects demonstrated relative improvement in AHI, but patients continued to have a significant number of respiratory events and episodes of flow limitation.? Subsequent treatment with a dental device led to further improvement in nocturnal respiration, but did not reduce AHI to a normal range on repeat polysomnography. In this study we demonstrate that bariatric surgery alone and in conjunction with a dental device may significantly reduce AHI but does not eliminate daytime fatigue and sleepiness. Systematic long term follow-up examining the persistence of sleep related abnormalities should be performed particularly if daytime fatigue or sleepiness is still present in patients with OSA after treatment with bariatric surgery alone.

Elevated nocturnal and morning blood pressure in patients with obstructive sleep apnea syndrome

Background The nocturnal nondipping and elevated morning blood pressure （BP） in patients with obstructive sleep apnea syndrome （OSAS） have not yet been well investigated in Chinese patients. This study aimed to describe the BP profile, and to elucidate the relationships between daytime BP and nighttime BP, and between evening BP and morning BP in patients with OSAS. Methods Twenty teaching hospital sleep centers in China were organized by the Chinese Medical Association to participate in this study and 2297 patients were recruited between January 2004 and April 2006. BP assessments were made at four time points （daytime, evening, nighttime and morning） and polysomnography （PSG） was performed and subjects were classified into four groups by their apnea-hypopnea index （AHI）： control, n=213 with AHI 〈5; mild, n=420 with AHI -〉5 and 〈15; moderate, n=460 with AHI -〉15 and 〈30; and severe, n=1204 with AHI -〉30. SPSS 11.5 software package was used for statistical analysis and figure drawing. Results All the average daytime, nighttime, evening and morning BPs were positively correlated with AHI and negatively correlated with nadir nocturnal oxygen saturation. The ratios of nighttime/daytime and morning/evening average BP were positively correlated with AHI. The ratio of nighttime/daytime systolic BP became a ＂reversed BP dipping＂ pattern until the classification reached severe, while the ratio of nighttime/daytime diastolic BP became reversed at moderate. Similarly, the ratio of morning/evening diastolic BP becomes reversed even at mild. Conclusions OSAS may result in higher BP levels at all four time points. The ratios of nighttime/daytime and morning/evening BP increase with increased AHI. The increasing of diastolic BP, which is inclined to rise more quickly, is not parallel with increasing systolic BP.

Ambulatory blood pressure monitoring in children with obstructive sleep apnea syndrome

Importance:The incidence of obstructive sleep apnea syndrome(OSAS)in children has increased year by year recently.Blood pressure research of OSAS children can help understand the occurrence of OSAS related complications.Early detection and intervention of blood pressure changes in children with OSAS can reduce the incidence of cardiovascular disease in later adulthood.Objective:To investigate the differences in blood pressure among different groups of snoring children and different sleep stages.Methods:Habitually snoring children(snoring frequency of≥3 nights per week)aged3 to 11 years were recruited from Beijing Children's Hospital from 1 January 2017 to 30 June 2018.All children underwent polysomnography,and their blood pressure was monitored and calculated by the pulse transit time.The children were divided into those with primary snoring(PS),mild OSAS,and moderate to severe OSAS according to their obstructive apnea-hypopnea index(OAHI).Results:In total,140 children were included.Ninety-seven had PS,24 had mild OSAS,and 19 had moderate to severe OSAS.There were no differences in age,sex,or body mass index z-score among the groups.Statistieally significant differences were found in the OAHI,oxygen desaturation index 3%,respiratory arousal index,and lowest oxygen saturation among the three groups.Children with moderate to severe OSAS had higher systolic and diastolic blood pressure than those with mild OSAS andPS(P<0.001).In all children,systolic and diastolic blood pressure was higher in the rapid eye movement(REM)sleep stage than in the non-REM sleep stage(P<0.05).Interpretation:Children with moderate to severe OSAS had higher blood pressure than those with PS and mild OSAS in all sleep stages.Blood pressure in the REM sleep stage was higher than that in other sleep stages in all groups of children.

Effects of plasma ghrelin, obestatin, and ghrelin/obestatin ratio on blood pressure circadian rhythms in patients with obstructive sleep apnea syndrome

Background Obstructive sleep apnea syndrome （OSAS） is strongly associated with obesity and with cardiovascular disease.Ghrelin and obestatin are two peptides from the same source but have opposite roles.Both of them can affect feeding and regulate vascular tune.The aim of this study was to investigate the relationship between plasma ghrelin,obestatin,the ratio of ghrelin and obestatin （G/O） and sleep parameters and blood pressure circadian rhythms in patients with OSAS.Methods This study enrolled 95 newly diagnosed over-weight OSAS patients （OSAS group）,30 body mass index （BMI）-match non-OSAS adults （over-weight group） and 30 non-OSAS normal weight adults （control group）.Polysomnography （PSG） was performed in the OSAS group and over-weight group.Blood pressure of all subjects was monitored by means of 24-hour ambulatory blood pressure monitoring.The concentration of plasma ghrelin and obestatin was detected by enzyme-linked immunosorbent assay （ELISA）.Results Plasma ghrelin levels in the OSAS group and over-weight group were significantly lower than that of the control group （P ＜0.05）.Plasma obestatin levels were lower in the over-weight group and OSAS group,but there was no significant difference among the three groups.The blood pressure in OSAS patients was higher,and there was a significant difference in all blood pressure parameters compared to the control group,and in the daytime average diastolic blood pressure （DBP）,nocturnal average systolic blood pressure （SBP） and DBP,DBP variability values as compared to over-weight subjects.Furthermore,there were significantly more non-dipper patterns of blood pressure （including hypertension and normotension） in the OSAS group than in the other two groups （P ＜0.01）.Correlation analysis showed that ghrelin levels had a significant correlation with BMI and nocturnal average DBP but not with PSG parameters.In contrast,the G/O ratio had a negative correlation with apnea-hypopnea index （AHI） （P ＜0.05）,as well as a strong positive correlation with the blood pressure variability values （P ＜0.01）.In multivariate analyses,AHI （P ＜0.05） and G/O （P ＜0.05）were independently related to SBP variability changes,while AHI （P ＜0.05）,G/O （P ＜0.01） and BMI （P ＜0.05） were independently related to DBP variability changes.Conclusions Our data show plasma ghrelin and obestatin levels were related to obesity in OSAS.Sleep apnea in OSAS patients could have led to an imbalance in G/O in the basis of obesity.Moreover,the imbalance may promote nighttime blood pressure elevation and affect blood pressure circadian disorder.

Effect of continuous positive airway pressure treatment on serum adiponectin level and mean arterial pressure in male patients with obstructive sleep apnea syndrome

Background Recent research suggested that obstructive sleep apnea syndrome （OSAS） might be independently associated with hypoadiponectinemia, which was linked to some complications of OSAS, such as hypertension, diabetes etc. This study was conducted to investigate the effect of continuous positive airway pressure （CPAP） treatment on changes of both serum adiponectin levels and mean arterial pressure and their possible links in male OSAS patients. Methods Twenty-three adult male patients with moderate-to-severe OSAS but without obesity, coronary heart disease and diabetes were recruited. Their blood samples were collected and morning mean arterial pressure （MAP） was measured before CPAP treatment and on day 3, 7, 14 of CPAP treatment respectively. The serum adiponectin concentration was tested with radioimmunoassay. Results Compared with the serum adiponectin level before CPAP treatment, no significant change was found in OSAS patients on day 3 and day 7 of CPAP treatment （P〉0.05）. It was not until day 14 of CPAP treatment did a significant elevation in serum adiponectin level occur （P〈0.01）. Meanwhile, the MAP showed no statistically significant difference among its levels before CPAP, on day 3 and day 7 of CPAP treatment （P〉0.05）. However, on day 14 of CPAP treatment, a significantly lower MAP than that obtained before treatment was observed （P〈0.05）. Conclusions CPAP treatment can gradually reverse hypoadiponectinemia and reduce MAP in OSAS patients. Hypoadiponectinemia might be involved in the pathogenesis of OSAS-mediated hypertension.

Relationship of daytime blood pressure and severity of obstructive sleep apnea among Chinese： a multi-center investigation in China

Background Epidemiologic studies have shown an independent and definite association between obstructive sleep apnea （OSA） and hypertension. This study aimed to define the association between daytime blood pressure and severity of OSA in Chinese population in mainland of China. Methods Twenty university hospital sleep centers in mainland of China were invited by the Chinese Medical Association （CMA） to participate in this epidemiologic study and 2297 consecutive patients （aged 18-85 years; 1981 males and 316 females） referred to these twenty sleep centers for evaluation of OSA between January 2004 and April 2006 were prospectively enrolled. Nocturnal polysomnography was performed in each patient, and disease severity was assessed based on the apnea-hypopnea index （AHI）. These patients were classfied into four groups： non-apneic control （control, n=257） with AHI 〈5 episodes/hour; mild sleep apnea （mild, n=402） with AHI 〉5 and 〈15 episodes/hour; moderate sleep apnea （moderate, n=460） with AHI 〉15 and 〈30 episodes/hour and severe sleep apnea （severe, n=1178） with AHI 〉30 episodes/hour. Daytime blood pressure measurements were performed under standardized conditions in each patient at 10 a.m. in office on the day of referring to sleep centers for getting average value. All the patients were requested to quit medications related to blood pressure for three days before the day of assessing. Results Both daytime systolic blood pressure and diastolic blood pressure values were significantly related to AHI positively （r = 0.201 and 0.276, respectively; both P values 〈0.001） and to nadir nocturnal oxygen saturation negatively （r = -0.215 and -0.277, respectively; both P values 〈0.001）, which were the parameters of OSA severity. In two special designed mean plots, means of daytime systolic and diastolic blood pressure increased gradually with increasing AHI. Beyond AHI of 61-65, this increasing trend reached a plateau. Conclusions The results showed that OSA severity was associated with daytime blood pressure until AHI of 61-65, providing evidence for early OSA management, especially in OSA patients with concomitant hypertension.

Effects of Continuous Positive Airway Pressure on Cognitive Deficits in Middle-aged Patients with Obstructive Sleep Apnea Syndrome： A Meta-analysis of Randomized Controlled Trials

Background： Current views on continuous positive airway pressure （CPAP） treatment to improve the cognitive deficits of patients with obstructive sleep apnea syndrome （OSAS） are controversial, so we performed a meta-analysis. Methods： A comprehensive literature search was undertaken in PubMed, CINAHL, Medline, Psyclnfo, EMBASE, Cochrane Library, CNKI, WanFang, VIP, and CBMdisc for studies published from June 1971 to July 2014. The outcome measures included neuropsychological tests of the 7 cognitive domains detailed below. Results： After screening the titles and abstracts and thoroughly reading the fuU text, we obtained 13 studies with little risk of bias that incorporated 1744 middle-aged obese participants with mild to severe OSAS. The studies were published from 1994 to 2012. Treatment durations varied from 1 to 24 weeks. The effect sizes of attention, vigilance, processing speed, working memory, memory, verbal fluency, and visuoconstructive skills domains were -0.10 （P = 0.24）, -0.12 （P = 0.04）, -0.08 （P = 0.16）, 0.00 （P = 0.95）, -0.04 （P = 0.30）, -0.06 （P = 0.34）, and -0.01 （P = 0.92）, respectively. Conclusions： Cognition partially improved in patients with OSAS after CPAP treatment. The only domain with significant improvement was vigilance. Rigorous randomized controlled trials need to be performed to obtain clear results.

Effect of continuous positive airway pressure therapy on glucose control

Obstructive sleep apnea (OSA) and diabetes mellitus are both highly prevalent disorders.There has been a recent recognition of an association between insulin resistance and sleep apnea.Continuous positive airway pressure (CPAP) has emerged as an effective therapy for treatment of OSA and has been shown to positively influence numerous pathophysiological factors that con-tribute to cardiovascular risk.There is emerging data that explores the influence of CPAP therapy,insulin sensitivity and glycemic control.In the current review,we examine this literature critically and formulate a synopsis that summarizes the current knowledge in this field.