Obesity, sleep apnea, aldosterone, and hypertension

An evaluation of the change in serum SCUBE-1 levels with CPAP treatment in patients with severe obstructive sleep apnea

OBJECTIVE

Signal peptide CUB-EGF domain-containing protein 1 (SCUBE-1) is a cell surface protein, wherein inflammation causes an increase in serum. The aim of this study was to compare serum SCUBE-1 levels in OSA patients and to investigate the serum SCUBE-1 change with CPAP treatment.

METHODS

Blood samples were obtained from 61 severe OSA patients and from 25 control subjects evaluated as simple snorers. The 61 patients with severe OSA were treated with CPAP therapy and were recalled for follow up after 1 year. Evaluation was made after 1 year of CPAP therapy.

RESULTS

Serum SCUBE-1 values were significantly higher in patients with severe OSA. The SCUBE-1 values significantly decreased after treatment with CPAP.

CONCLUSION

Serum SCUBE-1 values in OSA patients showed a significant reduction in SCUBE-1 levels following 1 year of CPAP treatment.

[Efficacy of weight management combined with uvulopalatopharyngoplasty for obesityrelated obstructive sleep apnea-hypopnea syndrome]

OBJECTIVE

To evaluate the clinical efficacy of weight management combined with pharyngoplasty for treatment of obesity-related obstructive sleep apnea-hypopnea syndrome (OSAHS).

METHODS

Sixty obese patients with OSAHS were randomly assigned into the combined treatment group and control group (n=30) and received treatment with uvulopalatopharyngoplasty (UPPP) combined with cognitive-behavioral-psychological intervention for family weight management and uvulopalatopharyngoplasty with conventional management. At 3 and 6 months of the treatment, the patients were examined for changes in body mass index (BMI), neck circumference, waist circumference, Epworth Sleepiness Scale (ESS) scores, apnea-hypopnea index (AHI), the lowest oxygen saturation (LSaO2) and the percentage of time with oxygen saturation below 90% (CT90).

RESULTS

After 6 months of treatment, the patients receiving the combined treatment showed significant reductions of BMI, neck circumference and waist circumference as compared with the measurements before treatment and with those in the control group (P < 0.01); these parameters showed no significant changes in the control group (P > 0.05). In the combined treatment group, the ESS score, CT90, AHI, and LSaO2 at 6 months were all superior to those in the control group (P < 0.01) and differed significantly cross different time points during the treatment, and their improvements were the most obvious after 6 months (P < 0.01). After 6 months of treatment, the combined treatment group had a similar cure rate with the control group (6.6% vs 7.1%; χ2=1.66, P > 0.05) but a significantly higher good response (defined as an AHI < 20 h-1 and an AHI reduction by ≥50%) rate (60% vs 35.7%; χ2=8.71, P < 0.01) and a higher overall response (a AHI reduction ≥50%) rate (83.3% vs 53.6%; χ2=10.62, P < 0.01).

CONCLUSIONS

Weight management combined with uvulopalatopharyngoplasty can produce a good clinical efficacy for treatment of OSAHS with obesity, and the patients should have strengthened continuous family weight management while receiving surgical treatment.

Primary Aldosteronism and Obstructive Sleep Apnea: Casual Association or Pathophysiological Link?

The coexistence of aldosterone oversecretion and obstructive sleep apnea is frequently observed, especially in patients with resistant hypertension, obesity, and metabolic syndrome. Since aldosterone excess and sleep apnea are both independently associated with an increased risk of cardiovascular disease, to investigate whether their coexistence might be attributed to common predisposing conditions, such as metabolic disorders, or to an actual pathophysiological interconnection appears of great importance. Fluid overload and metabolic abnormalities relating to aldosterone oversecretion may be implicated in obstructive sleep apnea development. Nocturnal intermittent hypoxia may in turn exacerbate renin-angiotensin-aldosterone system activity, thus leading to hyperaldosteronism. Furthermore, fat tissue excess and adipocyte secretory products might predispose to both sleep apnea and aldosterone oversecretion in subjects with obesity. Consistent with these evidences, obstructive sleep apnea frequently affects patients with primary aldosteronism. Conversely, whether primary aldosteronism is more prevalent in individuals affected by obstructive sleep apnea compared to the general population remains controversial.

Obesity and its cardiovascular effects

Obesity is described in terms of body fat percentage or body mass index (BMI), despite the fact that these measures do not give full insight about the body fat distribution. It is presently a consistently growing universal challenge since it has tripled in the last 10 years, killing approximately 28 million people each year. In this review, we aim to clarify the different results of obesity on the working and physiology of the cardiovascular system and to reveal changes in the obesity "paradox"-a variety of cardiovascular outcomes in typical/overweight people. Central fat build-up in ordinary/overweight populaces has been related to expanded occurrences of myocardial infarction, heart failure, or all-cause mortality when contrasted with the obese populace. These discoveries are additionally clarified as the abundance and prolonged vulnerability to free fatty acids (FFAs) in obesity. This has been believed to cause the myocardial substrate to move from glucose to FFAs digestion, which causes lipid gathering in cardiomyocytes, spilling over to other lean tissues, and prompting a general atherogenic impact. This cardiomyocyte lipid aggregation has been demonstrated to cause insulin resistance and cardiovascular hypertrophy, and to lessen the heart functions in general. There is a proof backing the fact that fat tissue is not only an energy reservoir, it also coordinates hormones and proinflammatory cytokines and deals with the energy transition of the body by putting away abundant lipids in diverse tissues.

Targeted sequencing analysis of the adiponectin gene identifies variants associated with obstructive sleep apnoea in Chinese Han population

Obstructive sleep apnoea (OSA) is a prevalent sleep disorder considered as an independent risk factor for cardiovascular consequences. It has a strong genetic background and is associated with hypoadiponectinaemia.Target sequencing of whole ADIPONQ gene was performed in 340 participants including 247 patients with OSA and 93 non-OSA participants. Polysomnography was used to diagnose OSA. The associations between variants and OSA were determined by multivariate regression analysis.Thirteen single nucleotide polymorphisms of ADIPOQ were identified in all subjects. Genotype frequencies at rs4686803 (P = .034), rs3774262 (P = .034), and rs2082940 (P = .045) were significantly different between OSA and non-OSA groups. Individuals carrying the CT/TT genotypes of rs4686803, GA/AA genotypes of rs3774262, and CT/TT genotypes of rs1063537 were associated with 2.295-, 2.295- and 2.155-fold increased risk of OSA respectively in dominant model, after adjusting for confounding effects. The subjects with the rs2082940 CC genotype were associated with decreased risk of OSA (OR: 0.455) in recessive model. Additionally, the apnoea-hypopnea index (AHI) was significantly increased in rs3774262 (GA/AA) (P = .001), rs4686803 (CT/TT) (P = .001), and rs1063537 (CT/TT) (P = .004) genotype individuals than those with rs3774262 (GG), rs4686803 (CC), and rs1063537 (CC) genotypes, respectively. The AHI was significantly decreased in individuals with ADIPOQ rs2082940 CC genotypes than in those with the CT and TT genotype (P = .007). Moreover, the stratified analysis found that the genotype of rs3774262 (GA/AA), rs4686803 (CT/TT), and rs1063537 (CT/TT) variants were associated with increased risk of OSA by 2.935-, 2.935- and 2.786-fold in overweight participants. The genotype of rs2082940 CC variants was associated with decreased risk of OSA (OR: 0.373) in overweight participants compared with rs2082940 CT/ TT genotypes.ADIPOQ variants rs3774262, rs4686803, rs1063537, and rs2082940 were associated with the prevalence of OSA in Chinese Han individuals.

Predictors of Sleep Apnea in the Canadian Population

Older age, obesity, hypertension, snoring, and excessive daytime sleepiness have been associated with sleep apnea. The objective of this study was to determine the prevalence (crude and adjusted), as well as the risk factors, of sleep apnea in the adult Canadian population. Data from the 2009 Sleep Apnea Rapid Response (SARR) questionnaire were used to identify the risk factors, and all sleep-related questions in the SARR questionnaire were used. The outcome variable of interest was health professional-diagnosed sleep apnea. Covariates of interest were demographic variables, population characteristics, respiratory and cardiovascular diseases, and enabling resources. The multiple logistic regression model adjusted for the clustering effect was used to analyze the data. Sleep apnea was diagnosed in 858,913 adults (3.4% of the population), and more men (65.4%) than women (34.6%) were diagnosed with sleep apnea. Multivariable logistic regression analysis indicated that age (45 and older), loud snoring, sudden awakening with gasping/choking (rare/sometimes and once or more a week), and nodding off/falling asleep in driving in the past 12 months were significantly associated with diagnosed sleep apnea. Predictive probability demonstrated that in overweight and obese persons, ≥15 minutes of daily exercise significantly decreased the risk of diagnosed sleep apnea. The conclusion of this study is that in the Canadian population, sleep apnea is associated with older age, loud snoring, and sleeping problems. The protective effect of exercise warrants further investigation.

Association of adiponectin level and obstructive sleep apnea prevalence in obese subjects

Obstructive sleep apnea (OSA) is prevalent in obese subjects. Plasma adiponectin level in obese subjects is decreased. Whether reduced adiponectin level is associated with OSA is unknown. Participants without a previous diagnosis of OSA or who have not been treated with continuous positive airway pressure were enrolled and parameters of interest were collected. Polysomnography was performed to evaluate the presence of OSA and the severity of OSA as indexed by the apnea-hypopnea index (AHI). Between-group differences were analyzed. Pearson correlation analysis was used to evaluate the association between body mass index (BMI) with plasma levels of adiponectin and C-reactive protein (CRP) and AHI; and the association between plasma adiponectin level with CRP and AHI was also evaluated. Logistic regression analysis was conducted to evaluate the association between per 1-SD standardized decrease of plasma adiponectin level and the prevalence of OSA using stepwise adjustment models. A total of 486 participants were enrolled and the mean BMI was 26.9 ± 6.2 kg/m with obesity prevalence of 28%; and the mean AHI was 12.6 ± 8.9 per sleep hour with OSA prevalence of 42%. The mean adiponectin level was 18.4 ± 10.6 μg/mL. Compared with the nonobese group, participants in the obese group had higher BMI, neck girth, waist circumference, and AHI (P < .05 for all comparisons). The prevalence of OSA (51% vs 37%) and the proportion of moderate OSA (49% vs 42%) were also significantly higher, while adiponectin level (14.6 ± 8.7 μg/mL vs 20.7 ± 10.5 μg/mL) was significantly lower. In the obese group, plasma adiponectin level was decreased gradually with the increasing severity of OSA, which was not observed in the nonobese group. BMI was negatively correlated with adiponectin while positively correlated with CRP and AHI; and adiponectin was negatively correlated with both CRP and AHI. After adjusted for covariates including BMI and waist circumference, adiponectin remained significantly associated with OSA prevalence with odds ratio of 1.20 (95% confidence interval 1.12-1.65). In summary, our preliminary study suggests that in obese subjects, plasma adiponectin level is associated with the prevalence of OSA.

Association of aldosterone excess and apnea-hypopnea index in patients with resistant hypertension

The present study was to investigate the association of aldosterone excess and apnea-hypopnea index (AHI) in patients with resistant hypertension. Patients with resistant hypertension were enrolled and baseline characteristics including plasma aldosterone concentration (PAC) and 24 h-urine aldosterone levels were collected and compared between groups with different degrees of AHI as assessed by polysomnography. Association of key variables and AHI was then evaluated by univariate and multiple linear regression analysis. A total of 534 patients with resistant hypertension were enrolled and mean age was 57 ± 11 years. Overall, mean number of AHI was 21.7 ± 9.6 and nearly 92.3% of resistant hypertensive patients had obstructive sleep apnea (OSA). Mean PAC and 24 h-urine aldosterone level was 12.4 ± 6.3 ng/dL and 13.1 ± 6.8 ug, respectively. Compared with other groups, participants in the severe OSA group (AHI ≥ 30) had significantly higher PAC and 24 h-urine aldosterone level. Multiple linear regression analysis showed that PAC and 24 h-urine aldosterone levels were positively associated with AHI, while spironolactone was negatively associated with AHI, independent of age, gender, body mass index, smoking, plasma renin activity and diuretics. OSA is highly prevalent in patients with resistant hypertension and both PAC and 24 h-urine aldosterone level are significantly associated with AHI.

OSA and Cardiac Arrhythmogenesis: Mechanistic Insights

A surge of data has reproducibly identified strong associations of OSA with cardiac arrhythmias. As an extension of epidemiologic and clinic-based findings, experimental investigations have made strides in advancing our understanding of the putative OSA and cardiac arrhythmogenesis mechanistic underpinnings. Although most studies have focused on the links between OSA and atrial fibrillation (AF), relationships with ventricular arrhythmias have also been characterized. Key findings implicate OSA-related autonomic nervous system fluctuations typified by enhanced parasympathetic activation during respiratory events and sympathetic surges subsequent to respiratory events, which contribute to augmented arrhythmic propensity. Other more immediate pathophysiologic influences of OSA-enhancing arrhythmogenesis include intermittent hypoxia, intrathoracic pressure swings leading to atrial stretch, and hypercapnia. Intermediate pathways by which OSA may trigger arrhythmia include increased systemic inflammation, oxidative stress, enhanced prothrombotic state, and vascular dysfunction. Long-term OSA-associated sequelae such as hypertension, atrial enlargement and fibrosis, ventricular hypertrophy, and coronary artery disease also predispose to cardiac arrhythmia. These factors can lead to a reduction in atrial effective refractory period, triggered and abnormal automaticity, and promote slowed and heterogeneous conduction; all of these mechanisms increase the persistence of reentrant arrhythmias and prolong the QT interval. Cardiac electrical and structural remodeling observed in OSA animal models can progress the arrhythmogenic substrate to further enhance arrhythmia generation. Future investigations clarifying the contribution of specific OSA-related mechanistic pathways to arrhythmia generation may allow targeted preventative therapies to mitigate OSA-induced arrhythmogenicity. Furthermore, interventional studies are needed to clarify the impact of OSA pathophysiology reversal on cardiac arrhythmogenesis and related adverse outcomes.

Does continuous positive airway pressure reduce aldosterone levels in patients with obstructive sleep apnea?

PURPOSE

Aldosterone is associated with the development of obstructive sleep apnea (OSA) and cardiovascular diseases. Continuous positive airway pressure (CPAP) is an effective treatment for OSA, but the impact of CPAP therapy on aldosterone levels in patients with OSA remains unclear. To address this issue, a meta-analysis was conducted to evaluate the effects of CPAP therapy on serum aldosterone levels in OSA.

METHODS

Two reviewers independently searched PubMed, Cochrane library, Embase, and Web of Science before March 2015. Information on characteristics of subjects, study design, and pre- and post-CPAP treatment of serum aldosterone was extracted for analysis. Standardized mean difference (SMD) was calculated to estimate the treatment effects of CPAP therapy.

RESULTS

A total of 5 studies involving 329 patients were pooled into this meta-analysis, including 3 observational studies and 2 randomized controlled studies. Results indicated significantly decreased aldosterone levels after CPAP therapy (SMD = -0.236, 95 % confidence interval (CI) = -0.45 to -0.02, z = 2.12, p = 0.034).

CONCLUSIONS

This meta-analysis suggested that CPAP therapy was associated with a decrease in serum aldosterone in patients with OSA. Further large-scale, well-designed interventional investigations are needed to clarify this issue.

Drug therapy of apparent treatment-resistant hypertension: focus on mineralocorticoid receptor antagonists

Apparent treatment-resistant hypertension (aTRH) is defined as blood pressure (BP) >140/90 mmHg despite three different antihypertensive drugs including a diuretic. aTRH is associated with an increased risk of cardiovascular events, including stroke, chronic renal failure, myocardial infarction, congestive heart failure, aortic aneurysm, atrial fibrillation, and sudden death. Preliminary studies of renal nerve ablation as a therapy to control aTRH were encouraging. However, these results were not confirmed by the Symplicity 3 trial. Therefore, attention has refocused on drug therapy. Secondary forms of hypertension and associated conditions such as obesity, sleep apnea, and primary aldosteronism are common in patients with aTRH. The pivotal role of aldosterone in the pathogenesis of aTRH in many cases is well recognized. For patients with aTRH, the Joint National Committee-8, the European Society of Hypertension, and a recent consensus conference recommend that a diuretic, ACE inhibitor, or angiotensin receptor blocker and calcium channel blocker combination be used to maximally tolerated doses before starting a 'fourth-line' drug such as a mineralocorticoid receptor (MR) antagonist. Although the best fourth-line drug for aTRH has not been extensively investigated, a number of studies summarized here show that an MR antagonist is effective in reducing BP when added to the standard multi-drug regimen.

Sleep-disordered breathing and resistant hypertension

Hypertension is a highly prevalent problem worldwide, affecting at least one third of the adult general population. Although the exact prevalence is uncertain, it is estimated that at least 15% to 20% of individuals with hypertension have resistant hypertension. Resistant hypertension has been shown to predict more adverse cardiovascular and renal outcomes. In 2003, the Joint National Committee on Prevention, Detection, Evaluation and Treatment of High Blood Pressure recognized obstructive sleep apnea (OSA) as an important cause of secondary hypertension. A large body of epidemiologic evidence has linked OSA to resistant hypertension, nondipping nocturnal blood pressure, as well as target organ damage, including left ventricular hypertrophy, arterial stiffness, and microalbuminuria. The importance of OSA as a risk factor for the development of hypertension independent of other confounding factors also was observed in a prospective longitudinal study. More importantly, OSA predicts an increased risk of adverse cardiovascular outcomes, mortality, and sudden cardiac death. This article discusses the associations between OSA and resistant hypertension and reviews the latest understanding on the pathophysiologic mechanisms of hypertension in OSA. Nocturnal continuous positive airway pressure therapy is regarded as the standard treatment for OSA. Prospective randomized controlled trials and meta-analyses of prospective randomized controlled trials within the past 10 years that have examined the effects of continuous positive airway pressure therapy on blood pressure control in patients with OSA with or without hypertension are reviewed and summarized. The majority of the trials suggest a modest but significant benefit on blood pressure control with continuous positive airway pressure therapy. Whether continuous positive airway pressure therapy may improve hard outcomes of patients with OSA and resistant hypertension warrants further investigation.

Excessive daytime sleepiness among rural residents in Saskatchewan

BACKGROUND

Obstructive sleep apnea (OSA) is a common diagnosis in clinical practice. Excessive daytime sleepiness may be a warning for possible OSA.

OBJECTIVES

To assess the prevalence of excessive daytime sleepiness as measured by the Epworth Sleepiness Scale (ESS) in a rural community population; potential risk factors for OSA were also assessed.

METHODS

In 2010, a baseline respiratory health questionnaire within the Saskatchewan Rural Health Study was mailed to 11,982 households in Saskatchewan. A total of 7597 adults within the 4624 (42%) respondent households completed the ESS questionnaire. Participants were categorized according to normal or high (>10) ESS scores. Data obtained included respiratory symptoms, doctor-diagnosed sleep apnea, snoring, hypertension, smoking and demographics. Body mass index was calculated. Multivariable logistic regression analysis examined associations between high ESS scores and possible risk factors. Generalized estimating equations accounted for the two-tiered sampling procedure of the study design.

RESULTS

The mean age of respondents was 55.0 years and 49.2% were male. The prevalence of ESS>10 and 'doctor diagnosed' OSA were 15.9% and 6.0%, respectively. Approximately 23% of respondents reported loud snoring and 30% had a body mass index >30 kg⁄m2. Of those with 'doctor-diagnosed' OSA, 37.7% reported ESS>10 (P<0.0001) and 47.7% reported loud snoring (P<0.0001). Risk of having an ESS>10 score increased with age, male sex, obesity, lower socioeconomic status, marriage, loud snoring and doctor-diagnosed sinus trouble.

CONCLUSIONS

High levels of excessive daytime sleepiness in this particular rural population are common and men >55 years of age are at highest risk. Examination of reasons for residual sleepiness and snoring in persons with and without sleep apnea is warranted.

Increased aldosterone: mechanism of hypertension in obesity

The prevalence of both obesity and hypertension are increasing worldwide. Hypertension is a common consequence of obesity. Increased central adiposity is associated with increased aldosterone levels and blood pressure in human beings. A number of small studies have shown an association between obesity-mediated hypertension and mechanisms directly linked to increased levels of aldosterone. These studies have shown a trend toward relatively greater blood pressure reduction using aldosterone-receptor blockers compared with other classes of antihypertensive agents. Other than treatment for weight loss, treatment of hypertension with specific antihypertensive medications that block or reduce aldosterone action are appropriate in obese patients. Further research is needed to understand the exact role of the adipocyte in obesity-mediated hypertension.

Relationship between aldosterone and the metabolic syndrome in patients with obstructive sleep apnea hypopnea syndrome: effect of continuous positive airway pressure treatment

Background

Metabolic syndrome (MS) occurs frequently in patients with obstructive sleep apnea-hypopnea syndrome (OSAHS). We hypothesized that aldosterone levels are elevated in OSAHS and associated with the presence of MS.

Methods

We studied 66 patients with OSAHS (33 with MS and 33 without MS) and 35 controls. The occurrence of the MS was analyzed according to the National Cholesterol Education Program Adult Treatment Panel III (NCEP ATP III) clinical criteria. Measurements of plasma renin activity (PRA), aldosterone, aldosterone:PRA ratio, creatinine, glucose, triglycerides, cholesterol and HDL cholesterol were obtained at baseline and after CPAP treatment.

Results

Aldosterone levels were associated with the severity of OSAHS and higher than controls (p = 0.046). Significant differences in aldosterone levels were detected between OSAHS patients with and without MS (p = 0.041). A significant reduction was observed in the aldosterone levels in patients under CPAP treatment (p = 0.012).

Conclusion

This study shows that aldosterone levels are elevated in OSAHS in comparison to controls, and that CPAP therapy reduces aldosterone levels. It also shows that aldosterone levels are associated with the presence of metabolic syndrome, suggesting that aldosterone excess might predispose or aggravate the metabolic and cardiovascular complications of OSAHS.

Trial registration

The study is not a randomized controlled trial and was not registered.

Obesity-related hypertension: pathogenesis, cardiovascular risk, and treatment--a position paper of the The Obesity Society and The American Society of Hypertension

In light of the worldwide epidemic of obesity, and in recognition of hypertension as a major factor in the cardiovascular morbidity and mortality associated with obesity, The Obesity Society and The American Society of Hypertension agreed to jointly sponsor a position paper on obesity-related hypertension to be published jointly in the journals of each society. The purpose is to inform the members of both societies, as well as practicing clinicians, with a timely review of the association between obesity and high blood pressure, the risk that this association entails, and the options for rational, evidenced-based treatment. The position paper is divided into six sections plus a summary as follows: pathophysiology, epidemiology and cardiovascular risk, the metabolic syndrome, lifestyle management in prevention and treatment, pharmacologic treatment of hypertension in the obese, and the medical and surgical treatment of obesity in obese hypertensive patients.

Obesity-related hypertension: pathogenesis, cardiovascular risk, and treatment: a position paper of The Obesity Society and the American Society of Hypertension

In light of the worldwide epidemic of obesity, and in recognition of hypertension as a major factor in the cardiovascular morbidity and mortality associated with obesity, The Obesity Society and the American Society of Hypertension agreed to jointly sponsor a position paper on obesity-related hypertension to be published jointly in the journals of each society. The purpose is to inform the members of both societies, as well as practicing clinicians, with a timely review of the association between obesity and high blood pressure, the risk that this association entails, and the options for rational, evidenced-based treatment. The position paper is divided into six sections plus a summary as follows: pathophysiology, epidemiology and cardiovascular risk, the metabolic syndrome, lifestyle management in prevention and treatment, pharmacologic treatment of hypertension in the obese, and the medical and surgical treatment of obesity in obese hypertensive patients.

Prevalence of High Epworth Sleepiness Scale scores in a rural population

BACKGROUND

Increased daytime sleepiness is an important symptom of obstructive sleep apnea (OSA). OSA is frequently underdiagnosed, and the Epworth Sleepiness Scale (ESS) can be a useful tool in alerting physicians to a potential problem involving OSA.

OBJECTIVE

To measure the prevalence and determinants of daytime sleepiness measured using the ESS in a rural community population.

METHODS

A community survey was conducted to examine the risk factors associated with ESS in a rural population in 154 households comprising 283 adults. Questionnaire information was obtained regarding physical factors, social factors, general medical history, family medical history, ESS score, and self-reported height and weight. Multivariable binary logistic regression analysis based on the generalized estimating equations approach to account for clustering within households was used to predict the relationship between a binary ESS score outcome (normal or abnormal) and a set of explanatory variables.

RESULTS

The population included 140 men (49.5%) and 143 women (50.5%) with an age range of 18 to 97 years (mean [± SD] 52.0±14.9 years). The data showed that 79.2% of the study participants had an ESS score in the normal range (0 to 10) and 20.8% had an ESS score >10, which is considered to be abnormal or high sleepiness. Multivariable regression analysis revealed that obesity was significantly associated with an abnormal or high sleepiness score on the ESS (OR 3.40 [95% CI 1.31 to 8.80).

CONCLUSION

High levels of sleepiness in this population were common. Obesity was an important risk factor for high ESS score.

Mineralocorticoid receptors in the pathophysiology of chronic kidney diseases and the metabolic syndrome

Recent studies indicate that aldosterone/mineralocorticoid receptor (MR) is a major contributor of chronic kidney disease (CKD) progression. Aldosterone/MR induces glomerular podocyte injury, causing the disruption of the glomerular filtration barrier and proteinuria. Conversely, MR antagonists substantially reduce proteinuria, which can be partly attributable to the protective effects on podocytes. Aldosterone excess, caused by adipocyte-derived aldosterone-releasing factors and other mechanisms, can be pathologically important in the renal complication of metabolic syndrome. A rat model of metabolic syndrome exhibits podocyte injury and proteinuria with serum aldosterone elevation, and the renal damage is prevented by MR blockade. Accumulating data also indicate that MR inhibition can confer renoprotection in a subgroup with low or normal aldosterone levels. We have recently identified the cross-talk between MR and small GTPase Rac1, providing one theoretical basis for the renoprotective effects of MR antagonists in non-high-aldosterone subjects. MR blockade can be a promising strategy for preventing CKD progression, and future clinical trials will conclusively determine the efficacy and tolerability of selective MR inhibition in CKD and metabolic syndrome.

Blood pressure dipping: ethnicity, sleep quality, and sympathetic nervous system activity

BACKGROUND

Blunted blood pressure (BP) dipping is an established predictor of adverse cardiovascular outcomes. Although blunted BP dipping is more common in African Americans than whites, the factors contributing to this ethnic difference are not well understood. This study examined the relationships of BP dipping to ethnicity, body mass index (BMI), sleep quality, and fall in sympathetic nervous system (SNS) activity during the sleep-period.

METHODS

On three occasions, 128 participants with untreated high clinic BP (130-159/85-99 mm Hg) underwent assessments of 24-h ambulatory BP (ABP), sleep quality, (evaluated by sleep interview, self-report, actigraphy) and sleep-period fall in sympathetic activity (measured by waking/sleep urinary catecholamine excretion).

RESULTS

Compared to whites (n = 72), African Americans (n = 56) exhibited higher sleep-period systolic (SBP) (P = 0.01) and diastolic BP (DBP) (P < 0.001), blunted SBP dipping (P = 0.01), greater BMI (P = 0.049), and poorer sleep quality (P = 0.02). SBP dipping was correlated with BMI (r = -0.32, P < 0.001), sleep quality (r = 0.30, P < 0.001), and sleep-period fall in sympathetic activity (r = 0.30, P < 0.001). Multiple regression analyses indicated that these three factors were independent determinants of sleep-period SBP dipping; ethnic differences in dipping were attenuated when controlling for these factors.

CONCLUSIONS

Blunted BP dipping was related to higher BMI, poorer sleep quality, and a lesser decline in sleep-period SNS activity. Although African-American ethnicity also was associated with blunted dipping compared to whites in unadjusted analyses, this ethnic difference was diminished when BMI, sleep quality, and sympathetic activity were taken into account.

Aldosterone, mortality, and acute ischaemic events in coronary artery disease patients outside the setting of acute myocardial infarction or heart failure

BACKGROUND

Recent studies have demonstrated that aldosterone levels measured in patients with heart failure or acute myocardial infarction (MI) are associated with long-term mortality, but the association with aldosterone levels in patients with coronary artery disease (CAD) outside these specific settings remains unknown. In addition, no clear mechanism has been elucidated to explain these observations. The present study was designed to evaluate the relationship between the level of aldosterone and the risk of death and acute ischaemic events in CAD patients with a preserved left ventricular (LV) function and no acute MI.

METHODS AND RESULTS

In 799 consecutive CAD patients referred for elective coronary angioplasty measurements were obtained before the procedure for: aldosterone (median = 25 pg/mL), brain natriuretic peptide (BNP) (median = 35 pg/mL), hsC-reactive protein (median = 4.17 mg/L), and left ventricular ejection fraction (mean = 58%). Patients with acute MI or coronary syndrome (ACS) who required urgent revascularization were not included in the study. The primary endpoint, cardiovascular death, occurred in 41 patients during a median follow-up period of 14.9 months. Secondary endpoints-total mortality, acute ischaemic events (acute MI or ischaemic stroke), and the composite of death and acute ischaemic events-were observed in 52, 54, and 94 patients, respectively. Plasma aldosterone was found to be related to BMI, hypertension and NYHA class, and inversely related to age, creatinine clearance, and use of beta-blockers. Multivariate Cox model analysis demonstrated that aldosterone was independently associated with cardiovascular mortality (P = 0.001), total mortality (P = 0.001), acute ischaemic events (P = 0.01), and the composite of death and acute ischaemic events (P = 0.004). Reclassification analysis, using integrated discrimination improvement (IDI) and net reclassification improvement (NRI), demonstrated incremental predictive value of aldosterone (P < 0.0001).

CONCLUSION

Our results demonstrate that, in patients with CAD but without heart failure or acute MI, the level of aldosterone is strongly and independently associated with mortality and the occurrence of acute ischaemic events.

Resistant hypertension and obstructive sleep apnea: the sparring partners

Enhanced target organ damage and cardiovascular morbidity represent common issues observed in both resistant hypertension and obstructive sleep apnea. Common pathophysiological features and risk factors justify their coexistence, especially in individuals with increased upper-body adiposity. Impaired sodium handling, sympathetic activation, accelerated arterial stiffening, and impaired cardiorenal hemodynamics contribute to drug-resistant hypertension development in obstructive sleep apnea. Effective CPAP therapy qualifies as an effective "add-on" to the underlying antihypertensive pharmacological therapy, and emerging evidence underlines the favorable effect of mineralocorticoid antagonists on both resistant hypertension and obstructive sleep apnea treatment.

Renin-angiotensin-aldosterone system in patients with sleep apnoea: prevalence of primary aldosteronism

Obstructive sleep apnoea (OSA) is a sleep disorder characterized by recurrent episodes of oxygen desaturation during sleep, representing an independent risk factor for cardiovascular disease, such as myocardial infarction, stroke, congestive heart failure and resistant hypertension. Several neurohormonal mechanisms have been suggested to account for blood pressure increases, such as sympathetic nervous system hyperactivity, oxidative stress, renin—angiotensin—aldosterone system (RAAS) activation, endothelin system activation, and endothelial dysfunction. The aim of this study was to evaluate the behaviour of RAAS and the presence of primary aldosteronism (PA) in these patients and possible correlations between RAAS and the severity of OSA. From October 2007 to November 2008 we studied 325 consecutive newly diagnosed hypertensive patients; 71 patients (21.8%) presented with clinical signs of sleep disorders, evaluated also through a specific questionnaire (Epworth Sleepiness Scale). In hypertensive patients with sleep disorders, 53 patients were affected by OSA; in this group 18 patients were affected by PA (five with aldosterone-producing adenoma (APA) and 13 with bilateral hyperplasia (IHA)); obesity was also demonstrated (BMI >" xbd="961" xhg="938" ybd="2430" yhg="2403"/> 30 kg/m2). Overall, in patients with OSA PRA levels correlated positively with apnoea/hypopnoea index (AHI; r = 0.35; p<0.01), and in all groups the waist circumference and the neck circumference were correlated positively with AHI ( r = 0.3 p<0.02 and r = 0.3 p<0.03, respectively). We revealed a high prevalence of PA in patients with OSA, and we can conclude that patients with hypertension and OSA, especially those who are newly diagnosed, must be evaluated for PA.

The cost of poor sleep: workplace productivity loss and associated costs

OBJECTIVE

To assess the impact of sleep disturbances on work performance/productivity.

METHODS

Employees (N = 4188) at four US corporations were surveyed about sleep patterns and completed the Work Limitations Questionnaire. Respondents were classified into four categories: insomnia, insufficient sleep syndrome, at-risk, and good sleep. Employer costs related to productivity changes were estimated through the Work Limitations Questionnaire. Performance/productivity, safety, and treatment measures were compared using a one-way analysis of variance model.

RESULTS

Compared with at-risk and good-sleep groups, insomnia and insufficient sleep syndrome groups had significantly worse productivity, performance, and safety outcomes. The insomnia group had the highest rate of sleep medication use. The other groups were more likely to use nonmedication treatments. Fatigue-related productivity losses were estimated to cost $1967/employee annually.

CONCLUSIONS

Sleep disturbances contribute to decreased employee productivity at a high cost to employers.