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The role of the primary care physician in recognizing obstructive sleep apnea.

BACKGROUND: Obstructive sleep apnea (OSA) is a common disorder among middle-aged adults. However, OSA is a recently described disorder for which most primary care physicians do not have formal training. The primary objectives of this article are to evaluate what percentage of patients referred by primary care physicians for sleep studies had OSA; to characterize the clinical features of these patients and compare them with our known OSA population; and to determine whether primary care physicians asked key questions contained in a work sheet to make the diagnosis of OSA. METHODS: A retrospective chart review at a hospital-based sleep center that is accredited to evaluate all sleep disorders, not just OSA. The health maintenance organization is a staff model one. PATIENTS: Sixty-nine patients who were referred for a sleep study by a health maintenance organization internist or family practitioner between June 1, 1994, and May 30, 1995. RESULTS: Ninety-six percent of the 68 patients referred for polysomnography had OSA. Most were very symptomatic and obese. These 68 patients represent 0.13% of the primary care patient panel. In addition, most of the patients were referred by a few physicians; 6 (11%) of the 55 physicians ordered 33% of the 68 studies. CONCLUSIONS: Primary care physicians did recognize obese patients with prominent symptoms of sleep apnea. However, only a small percentage of their patient panel was referred, suggesting that this condition is still underdiagnosed. This seems particularly true as most of the sleep studies were ordered by a small group of physicians. Future work incorporating educational interventions is necessary to improve detection and treatment of OSA.

Adult↗

Polysomnographic and clinical findings in children with obstructive sleep apnea.

A retrospective study was conducted to determine which types of children might have polysomnographic findings that are most compatible with obstructive sleep apnea (OSA). The charts of 93 patients who were aged 18 months to 12 years were examined. All 93 patients had symptoms that were initially suggestive of OSA, and they underwent polysomnography. The types of presenting symptoms and associated illnesses were noted. Physical findings, including height, weight, and tonsil size, were examined. Of 93 patients with symptoms that were suggestive of OSA, 34 met sleep study criteria for OSA. In 44 patients, OSA was not demonstrated, and 15 patients had other results. On the basis of age, sex, and symptoms, no significant differences could be found between the group with OSA and the group with normal polysomnographic findings. Cor pulmonale, tonsil hypertrophy, and failure to thrive were associated with OSA. Surprisingly, obesity was not significantly associated with OSA.

Child↗

Circadian rhythm of autonomic activity in patients with obstructive sleep apnea syndrome.

BACKGROUND AND HYPOTHESIS: Although the immediate effects of sleep apnea on hemodynamics and the neurological system have been studied, little is known about the circadian rhythm of heart rate variability in patients with obstructive sleep apnea syndrome (OSAS). The purpose of the present study was to investigate the effects of sleep apnea on the autonomic activity during daytime, which may play some role in the pathogenesis of cardiovascular complications in OSAS. METHODS: We studied 18 middle-aged male patients with OSAS and 10 age-matched control subjects. Patients with OSAS were classified according to the severity of OSAS: patients with an apnea index (AI) < 20 were considered to have mild OSAS (Group 1, n = 8) and patients with an AI > or = 20 were considered to have severe OSAS (Group 2, n = 10). Heart rate variability was calculated from the 24-h ambulatory electrocardiograms by the Fourier transformation. Power spectra were quantified at 0.04-0.15 Hz [low frequency power (LF)ln(ms2)] and 0.15-0.40 Hz [high frequency power (HF)ln(ms2)]. The HF component and the ratio of LF to HF were used as indices of the parasympathetic and sympathetic activity, respectively. RESULTS: The circadian rhythms of the LF, HF, and LF/HF ratio differed significantly in Group 2 compared with Group 1 and control subjects (p < 0.05). Hypertension (> 160/95 mm Hg) was found in 7 (70.0%) of 10 patients in Group 2, and in 1 (12.5%) of 8 patients in Group 1. Echocardiographic evidence of left ventricular hypertrophy (LVH) (an interventricular septal thickness or a left ventricular posterior wall thickness > or = 12 mm) was found in 3 (30.0%) of 10 patients in Group 2, and in 1 (12.5%) of 8 patients in Group 1. The mean HF from 4 A.M. to 12 noon was significantly lower in Group 2 than in Group 1 and the control group, and it correlated significantly with the lowest nocturnal SaO2 (r = 0.58, p < 0.05). The mean LF/HF ratio during the same period was significantly higher in Group 2 than in Group 1 and the control group, and it correlated significantly with total time of the nocturnal oxygen saturation < 90% (r = 0.64, p < 0.005) and the lowest nocturnal SaO2 (r = 0.56, p < 0.05). Ventricular tachycardia was found in the early morning in one patient, ST-T depression in two patients, and sinus arrest in two patients in Group 2. CONCLUSION: These findings suggest that sleep-disordered breathing associated with severe oxygen desaturation might influence heart rate variability not only during sleep but also during daytime. OSAS per se might contribute to altered circadian rhythm in autonomic activity leading to the development of cardiovascular diseases.

Adult↗

Twenty-four-hour ambulatory oxygen desaturation and electrocardiographic recording in obstructive sleep apnea syndrome.

BACKGROUND: Although nocturnal pulseoximetry is routinely performed in obstructive sleep apnea syndrome (OSAS), pulseoximetry over a 24-h period has not been studied. HYPOTHESIS: The purpose of the study was to determine whether simultaneous 24-h oxygen desaturation and electrocardiographic (ECG) recording might be used to screen for daytime sleep sequelae in patients with OSAS. METHODS: Simultaneous recording of arterial oxygen saturation (SpO2) and ECG was conducted over a 24-h period in 18 male patients with OSAS (mean age 51.3 years) who were diagnosed by standard polysomnography (PSG), and in 15 age-matched healthy subjects (mean age 52.7 years) as controls to evaluate circadian variation of these parameters. The measures of heart rate variability (HRV) were calculated from 24-h ambulatory ECGs. Seventeen patients with OSAS showed excessive daytime sleepiness (EDS). We calculated the duration in which SpO2 decreased to < 90% (duration of SpO2 < 90%). The number of apnea/hypopneas per hour (AHI) during sleep was investigated with Apnomonitors (Chest MI, Co., Tokyo) on the same day as the SpO2 recordings. RESULTS: Controls showed no episodes of oxygen desaturation. In patients with OSAS, driving (33.3% of patients with OSAS) was the most common activity in which SpO2 decreased to < 90%, followed by daytime napping (27.8%) and resting after meals (22.2%). The duration of SpO2 < 90% over a 24-h period correlated significantly with the duration levels recorded during sleep (r = 0.99, p < 0.05) and in the afternoon (r = 0.62, p < 0.05), and with the AHI (r = 0.55, p < 0.05), but not with the duration of SpO2 < 90% in the morning. The number of ventricular premature beats correlated significantly with the duration of SpO2 < 90% for a 24-h period, but not with measures of HRV. Ventricular tachycardia was found in two (11.1%) and ST-T depression in three patients (16.6%) with underlying cardiac diseases. CONCLUSION: Our results suggest that daytime sleep attacks accompanied by oxygen desaturation in patients with moderate to severe OSAS may contribute to the occurrence of traffic or cardiovascular accidents. We conclude that 24-h ambulatory recordings of SpO2 and ECG are useful for screening for daytime sleep sequelae associated with the potential risk of this pathology in OSAS during social activities.

Adult↗

Acoustic arousal responses in children with obstructive sleep apnea.

Our objectives were to study the arousal responses to nonrespiratory (acoustic) stimuli in children with obstructive sleep apnea syndrome (OSAS). The acoustic arousal response was studied in children with OSAS due to adenotonsillar hypertrophy compared to normal, age-matched children. Acoustic stimuli were delivered incrementally from 30-100 dB during stage 2, slow wave sleep, and rapid eye movement (REM) sleep. The percentage of children who aroused in response to acoustic stimuli, and the arousal threshold (i.e., sound level at which arousal occurred), were compared between groups and sleep stages. The percentage of children who aroused was similar between children with OSAS and controls. The percentage of children who aroused was lower during slow wave sleep than REM sleep and stage 2 in both OSAS and controls. There were no statistically significant differences in acoustic arousal threshold between OSAS and control children. There was no difference in arousal response to moderate acoustic stimulation between children with OSAS and controls. These results contrast with previous data showing blunted arousal responses to hypercapnia and upper airway loading during sleep in children with OSAS, suggesting that children with OSAS have an arousal deficit specific to respiratory stimuli. However, further studies evaluating arousal to both respiratory and nonrespiratory stimuli in the same subjects are needed.

Acoustic Stimulation↗

Insulin and obstructive sleep apnea in obese Chinese children.

OBJECTIVE: In adults, obstructive sleep apnea (OSA) is associated with insulin resistance and dyslipidemia. We aimed to establish correlation between OSA, serum lipid profile, and insulin levels in obese snoring children. METHODS: Consecutive obese children with habitual snoring were recruited. They underwent physical examination, overnight polysomnography (PSG), and metabolic studies. OSA was diagnosed if apnea hypopnea index (AHI) > 1.0, and cases were considered to have moderate to severe OSA if AHI > 10. RESULTS: Ninety-four obese subjects with habitual snoring were studied. Seventy-three subjects were male and the median age of the studied group was 12.0 years (IQR 9.7-13.9). None of the subjects had active cardiopulmonary disease, and the BMI values of our subjects were >95th percentile using local reference charts. Sixty subjects had OSA, 47 being mild, and 13 being moderate to severe OSA. Multiple logistic regression analysis revealed that saturation nadir and insulin levels were significantly associated with OSA. CONCLUSION: OSA is prevalent among obese children with habitual snoring and insulin is independently associated with the condition. Its role in the cardiovascular complications of childhood sleep apnea is worthy of further exploration.

Adolescent↗

Preoperative predictors of difficult intubation in patients with obstructive sleep apnea syndrome.

PURPOSE: It has been speculated that the severity of obstructive sleep apnea syndrome (OSAS) is related to difficult intubation. However, this has not been confirmed in OSAS patients. Thus, we undertook a retrospective study to assess this relationship in patients who had undergone uvulopalatopharyngoplasty (UPPP) surgery for OSAS. METHODS: A retrospective case-control study was undertaken following approval from the Institutional Review Board on human studies. The data from 90 patients with a polysomnograph-confirmed diagnosis of OSAS, who had undergone UPPP surgery under general anesthesia, were used to evaluate the apnea-hypopnea index (AHI), the preoperative lowest arterial saturation, the occurrence of difficult intubation as assessed by the operator intubation difficulty scale score, extubation time, lowest arterial saturation in postanesthesia care unit, and length of stay in postanesthesia care unit. We compared OSAS patients with 90 age and sex-matched control patients with respect to the prevalence of difficult intubation. RESULTS: The prevalence of difficult intubation was higher in the OSAS group than in the control group (16.7% vs 3.3%, P = 0.003). When evaluating the OSAS group according to the occurrence of difficult intubation, AHI was significantly higher in the difficult intubation subgroup (67.4 +/- 22.5 vs 49.9 +/- 28.0, P = 0.026), and patients with an AHI >or= 40 showed a significantly higher prevalence of difficult intubation. CONCLUSION: This study shows that the occurrence of difficult intubation can be predicted using AHI in patients who undergo UPPP surgery for OSAS.

Adult↗

Testosterone levels in obese male patients with obstructive sleep apnea syndrome: relation to oxygen desaturation, body weight, fat distribution and the metabolic parameters.

To investigate the impact of obstructive sleep apnea syndrome (OSAS) on testosterone levels and on the main parameters of the metabolic syndrome in abdominally obese men, 15 male subjects with abdominal obesity phenotype and polysomnographic diagnosis of OSAS (OB-OSAS) and 15 controls matched for age and anthropometric parameters (OB) were investigated. Anthropometry, SHBG, sex hormones and several parameters of the metabolic syndrome were measured. Only subjects with an Epworth Sleepiness Score greater than 10 underwent a polysomnographic study with calculation of the number of desaturation rates per sleeping hour (ODI), the minimal oxygen saturation during each desaturation episode (minSaO2) and the mean minimal arterial oxygen saturation for the whole night period (MminSaO2). Both total and free testosterone levels were lower in OB-OSAS than in OB patients. A negative correlation between polysomnographic parameters (ODI, minSaO2 and MminSaO2) and testosterone levels was found. The relationship between total and free testosterone and ODI persisted after adjusting for body mass index (BMI) and waist (W) values. Triglyceride and uric acid levels were significantly higher in OB-OSAS than in OB patients. A negative correlation between testosterone and acid uric level and a positive correlation between testosterone and HDL-cholesterol level was found, regardless of BMI and W circumference, particularly in the OB-OSAS group. Our study suggests that, in patients with obesity and OSAS, the severity of hypoxia during sleeping hours may be an additional factor in reducing testosterone levels, regardless of BMI and abdominal fatness. This may contribute in worsening metabolic abnormalities which, in men with OSAS, exceed those expected on the basis of degree of obesity and pattern of fat distribution.

Adipose Tissue↗

[Obstructive sleep apnea-related cardiovascular disease].

The clinical spectrum of obstructive sleep apnea-(OSA-)related cardiovascular disease (CVD) comprises systemic arterial hypertension (prevalence: 40-60%), pulmonary hypertension (20-30%), coronary artery disease (20-30%), congestive heart failure (5-10%), and stroke (5-10%). During sleep, heart rhythm disorders such as atrioventricular blocks, sinus arrests and atrial fibrillation can be induced by OSA. OSA-related CVD mainly affects those patients with an apnea-hypopnea index > 30/h and, if left untreated, is linked to increased mortality. Epidemiologic data have clearly shown that cardiovascular risk is increased in OSA independent of confounding factors such as obesity and concomitant metabolic disease. In recent years, the pathophysiology of OSA-related CVD has been further elucidated showing that apart from the well-known sympathetic activation, increased oxidative stress and pro-inflammatory changes seem to play major roles. Furthermore, studies using high resolution ultrasonography have demonstrated endothelial dysfunction and enhanced atherosclerosis in these patients. Finally, animal models of OSA have delineated that daytime arterial hypertension is the consequence of the OSA-associated chronic intermittent hypoxia. Therapy of OSA by continuous positive airway pressure (CPAP) ventilation exerts cardioprotective effects. It has been shown to rectify the vascular micromilieu, restore endothelium-dependent vasodilation, lower 24-h blood pressure, eliminate nocturnal heart rhythm disorders, and improve left ventricular function. Furthermore, long-term CPAP therapy leads to a reduction in important clinical endpoints such as the rates of myocardial infarction and stroke.

Animals↗

Reactive oxygen metabolites (ROMs) as an index of oxidative stress in obstructive sleep apnea patients.

STUDY OBJECTIVES: Obstructive sleep apnea syndrome (OSA) is accompanied by oxygen desaturation and arousal from sleep. Free oxygen radicals are highly reactive molecules which could be produced by the OSA phenomenon of hypoxia/reoxygenation: cyclical alterations of arterial oxygen saturation with oxygen desaturation developing in response to apneas followed by resumption of oxygen saturation during hyperventilation. On the basis of these considerations, it was hypothesized that OSA may be linked to increased oxidative stress. MATERIAL AND METHODS: Twenty-six participants gave an interview during which a physician asked them about their age, smoking habits, and symptoms such as excessive daytime sleepiness and snoring. Physical examination and polysomnography were performed during their hospitalization. Reactive oxygen metabolites (ROMs) were measured in blood samples by the diacron reactive oxygen metabolites (D-ROM) test. RESULTS: Twenty-one out of 26 subjects had an apnea/hypopnea index greater than 5 (OSA group). The measurement of free radicals was high in OSA patients. Furthermore, ROMs values in OSA patients were linearly correlated with the apnea/hypopnea index (R = 0.426; p = 0.042). The predictive value of a positive D-ROM test is 81%. CONCLUSIONS: ROMs were elevated in patients with OSA. When OSA was severe, similarly the value of ROMs in blood samples was enhanced, and the probable underlying mechanism for these events is the hypoxia/reoxygenation phenomenon.

Female↗

Long-term effects of nasal continuous positive airway pressure on vasodilatory endothelial function in obstructive sleep apnea syndrome.

Obstructive sleep apnea syndrome (OSAS) is associated with a dysfunction of vascular endothelial cells. The aim of this study was to investigate long-term improvement of endothelial dysfunction in OSAS with nasal continuous positive airway pressure (nCPAP) treatment. We investigated endothelium-dependent and endothelium-independent vasodilatory function in patients with OSAS using the hand vein compliance technique. Dose-response curves to endothelium-dependent vasodilator bradykinin were obtained in 16 subjects with OSAS before and after 6 months of nCPAP therapy and in 12 control subjects without OSAS. Maximum dilation (Emax) to bradykinin, being impaired in all OSAS patients, was completely restored with nCPAP. Mean Emax to bradykinin rose from 54.9+/-18.5 to 108.2+/-28.7% with 164.4+/-90.0 nights of nCPAP therapy (p<0.0001; Emax healthy controls, 94.8+/-9.5%). At treatment follow-up, endothelium-dependent vasodilatory capacity was not significantly different in nCPAP-treated OSAS patients vs healthy controls. Mean vasodilation with endothelium independently acting nitroglycerin was not altered initially and did not change with nCPAP therapy indicating that nCPAP restored endothelial cell function and not unspecific, endothelium-independent factors. These results suggest that regular nocturnal nCPAP treatment leads to a sustained restoration of OSAS-induced impaired endothelium-dependent nitric oxide-mediated vasodilation, suggesting an improvement of systemic endothelial dysfunction in patients studied.

Anthropometry↗

Activation of nuclear factor kappaB in obstructive sleep apnea: a pathway leading to systemic inflammation.

Apnea-induced hypoxia and reoxygenation, which generates reactive oxygen species, may activate the oxidant-sensitive, proinflammatory transcription factor nuclear factor kappaB (NF-kappaB), increasing systemic inflammation in obstructive sleep apnea. We measured NF-kappaB activity in circulating neutrophils and plasma levels of NF-kappaB-controlled gene products, soluble E (sE)-selectin and soluble vascular cell adhesion molecule-1 (sVCAM-1) in control subjects and in obstructive sleep apnea (OSA) patients. To confirm a causal link with OSA, we reassessed these parameters after nasal continuous positive airway pressure (CPAP) therapy. Twenty-two subjects undergoing evaluation for symptoms of sleep-disordered breathing were grouped by apnea hypopnea index: control, less than 5/h; mild to moderate OSA, 11-40/h; severe OSA, more than 40/h. A morning venous blood sample was obtained. Neutrophils were isolated, and NF-kappaB activity was determined by electrophoretic mobility shift assay. Plasma sE-selectin and sVCAM-1 were assayed by enzyme-linked immunosorbent assay. Neutrophils in mild to moderate and severe OSA patients showed 4.8- and 7.9-fold greater NF-kappaB binding activity compared with control subjects (p<0.0001). The degree of NF-kappaB activation was positively correlated with indices of apnea severity. In five severe OSA patients, 1 month of CPAP therapy decreased neutrophil NF-kappaB activation to control levels. sE-selectin and sVCAM concentrations were reduced by CPAP in four of these five subjects. OSA leads to NF-kappaB activation, which may constitute an important pathway linking OSA with systemic inflammation and cardiovascular disease.

Adult↗

Evidence for activation of nuclear factor kappaB in obstructive sleep apnea.

Obstructive sleep apnea (OSA) is a risk factor for atherosclerosis, and atherosclerosis evolves from activation of the inflammatory cascade. We propose that activation of the nuclear factor kappaB (NF-kappaB), a key transcription factor in the inflammatory cascade, occurs in OSA. Nine age-matched, nonsmoking, and non-hypertensive men with OSA symptoms and seven similar healthy subjects were recruited for standard polysomnography followed by the collection of blood samples for monocyte nuclear p65 concentrations (OSA and healthy groups). In the OSA group, p65 and of monocyte production of tumor necrosis factor alpha (TNF-alpha) were measured at the same time and after the next night of continuous positive airway pressure (CPAP). p65 Concentrations in the OSA group were significantly higher than in the control group [median, 0.037 ng/microl (interquartile range, 0.034 to 0.051) vs 0.019 ng/microl (interquartile range, 0.013 to 0.032); p = 0.008], and in the OSA group were significantly correlated with apnea-hypopnea index and time spent below an oxygen saturation of 90% (r = 0.77 and 0.88, respectively) after adjustment for age and BMI. One night of CPAP resulted in a reduction in p65 [to 0.020 ng/mul (interquartile range, 0.010 to 0.036), p = 0.04] and levels of TNF-alpha production in cultured monocytes [16.26 (interquartile range, 7.75 to 24.85) to 7.59 ng/ml (interquartile range, 5.19 to 12.95), p = 0.01]. NF-kappaB activation occurs with sleep-disordered breathing. Such activation of NF-kappaB may contribute to the pathogenesis of atherosclerosis in OSA patients.

Adult↗

Delayed Diagnosis of Obstructive Sleep Apnea: Don't Ask, Don't Tell.

To define the patterns of referral of adult patients with obstructive sleep apnea syndrome (OSAS) for diagnostic sleep testing, we studied 97 consecutive patients with OSAS (Apnea/Hypopnea Index >/= 20) referred to the Center for Sleep and Ventilatory Disorders, an American Sleep Disorders Association-accredited university sleep center. Chart review and semi-structured patient telephone interview quantified the time between the onset of any major feature of OSAS and referral to the sleep center, as well as the time between the first OSAS complaint to a health care provider and referral to the center. The average time elapsed between first recognition by the patient of a major feature of OSAS to sleep center referral was 87.5 months (range, 1 to 480 months). Only 4% of referrals were made as a result of the clinician eliciting a history of sleep-related complaints. Once OSAS-related features were apparent to the clinician, the average time to referral for diagnostic testing was 7.9 months (range, 0 to 128 months). These data suggest that both a lack of reporting of symptoms by OSAS patients and a lack of obtaining appropriate sleep history by health care providers contribute to a significant delay in diagnosis of OSA.

Journal Article↗

Obstructive sleep apnea.

The high prevalence of obstructive sleep apnea (OSA) has only recently been appreciated, in part because the symptoms and signs of chronic sleep disruption are often overlooked in spite of their debilitating consequences. They typically develop insidiously during a period of years. We now know that the lives of millions of people each year are significantly impaired by the sequelae of OSA. Many of these patients go unrecognized, with tremendous medical and economic consequences for individual patients and for society. Evidence indicates that chronic, heavy snoring may be associated with increased long-term cardiovascular and neurophysiologic morbidity. Therefore considerable interest lies in the study of the epidemiology and the natural history of these related disorders. The fundamental problem in OSA is the periodic collapse of the pharyngeal airway during sleep. The pathophysiology of this phenomenon is reviewed in some detail. During apneas caused by obstruction, airflow is impeded by the collapsed pharynx in spite of continued effort to breathe. This causes progressive asphyxia, which increasingly stimulates breathing efforts against the collapsed airway, typically until the person is awakened. Hypopneas predominate in some patients and are caused by partial pharyngeal collapse. The clinical sequelae of OSA relate to the cumulative effects of exposure to periodic asphyxia and to sleep fragmentation caused by apneas and hypopneas. Some patients with frequent, brief apneas and hypopneas and normal underlying cardiopulmonary function may have considerable sleep disruption without much exposure to nocturnal hypoxia. Patients with sleep apnea often have excessive daytime sleepiness. As the disorder progresses, sleepiness becomes increasingly irresistible and dangerous, and patients develop cognitive dysfunction, inability to concentrate, memory and judgment impairment, irritability, and depression. These problems may lead to family and social problems and job loss. Cardiac and vascular morbidity in OSA may include systemic hypertension, cardiac arrhythmias, pulmonary hypertension, cor pulmonale, left ventricular dysfunction, stroke, and sudden death. The challenge for the clinician is to routinely consider the diagnosis and to incorporate several basic questions in the historical review of systems regarding daytime or inappropriate sleepiness. The diagnosis of OSA is made with polysomnography, and the decision to treat is based on an overall assessment of the severity of sleep-disordered breathing, sleep fragmentation, and associated clinical sequelae. The therapeutic options for the management of OSA are reviewed. Recognition and appropriate treatment of OSA and related disorders will often significantly enhance the patient's quality of life, overall health, productivity, and safety on the highways.

Adult↗

NARES: a risk factor for obstructive sleep apnea?

BACKGROUND: Nonallergic rhinitis with eosinophilia syndrome (NARES) constitutes a rare nasal condition characterized by a chronic, eosinophilic inflammation. Patients' major complaints constitute nasal congestion and rhinorrhea. Obstructive sleep apnea syndrome (OSAS) is a potentially life-threatening condition characterized by recurrent episodes of obstruction of the upper airways resulting in oxygen desaturation. Nasal congestion constitutes one predisposing factor for OSAS. OBJECTIVE: The purpose was to study whether NARES constitutes a risk factor for OSAS. METHODS: The study included 26 patients presenting typical symptoms of sleep apnea. Ten patients were diagnosed to suffer from NARES (mean age 56.8 +/- 12.5, body mass index [BMI] 29.3 kg/m(2) +/- 2.8; 9 men:1 woman) and were compared with 16 age- and BMI-matched individuals (mean age 58.8 +/- 11.6, BMI 29.7 kg/m(2) +/- 3.8, 16 men) without any nasal inflammation, such as allergic rhinitis, sinusitis, nasal polyposis, or vasomotor rhinitis. All patients were tested by polysomnography for an OSAS. RESULTS: Patients suffering from NARES revealed significantly (P <.01) impaired polysomnographic parameters (hypopnea index, apnea-hypopnea index, mean and minimal oxygen saturation) compared with patients without any nasal inflammation. CONCLUSIONS: Our data point to NARES as a risk factor for the induction or augmentation of OSAS. NARES patients suffered from severe OSAS, whereas nondiseased individuals suffered only from moderate OSAS, according to the criteria of the American Academy of Sleep Medicine. Our data support results of others, suggesting chronic nasal inflammation to cause OSAS. Mechanisms for our observations are not fully understood yet. Nasal obstruction or neuronal reflexes might be involved.

Aged↗

Benefits of obstructive sleep apnoea treatment in coronary artery disease: a long-term follow-up study.

AIM: The aim of this long-term prospective study was to evaluate the effect of treating obstructive sleep apnoea (OSA) on the rate of cardiovascular events in coronary artery disease (CAD). METHODS AND RESULTS: We prospectively studied 54 patients (mean age 57.3 +/- 10.1 years) with both CAD (> or = 70% coronary artery stenosis) and OSA (apnoea-hypopnoea index > or = 15). In 25 patients, OSA was treated with continuous positive airway pressure (n=21) or upper airway surgery (n=4); the remaining 29 patients declined treatment for their OSA. The median follow-up was 86.5 +/- 39 months. The two groups were similar at baseline in age, body mass index, smoking history, hypertension, hypercholesterolaemia, diabetes mellitus, number of diseased vessels, left ventricular ejection fraction, and CAD therapy. Treatment of risk factors other than OSA was similar in the two groups. The endpoint (a composite of cardiovascular death, acute coronary syndrome, hospitalisation for heart failure, or need for coronary revascularisation) was reached in 6 (6/25, 24%) and 17 (17/29, 58%) patients with and without OSA treatment, respectively (P<0.01). OSA treatment significantly reduced the risk of occurrence of the composite endpoint (hazard ratio 0.24; 95% confidence interval, 0.09-0.62; p<0.01) and of each of its components. CONCLUSIONS: Our data indicate that the treatment of OSA in CAD patients is associated with a decrease in the occurrence of new cardiovascular events, and an increase in the time to such events.

Body Mass Index↗

Obstructive sleep apnoea is independently associated with an increased prevalence of metabolic syndrome.

AIMS: Obstructive sleep apnoea (OSA) is associated with increased cardiovascular morbidity and mortality. Although it was previously assumed that this was due to its relation with obesity, recent data suggest that OSA is independently associated with the cardiovascular risk factors that comprise metabolic syndrome, including hypertension, insulin resistance, impaired glucose tolerance, and dyslipidaemia. However, as previous studies have only considered these variables individually, it has not been possible to determine the overall association of OSA with this syndrome. METHODS AND RESULTS: We recruited 61 male subjects with OSA and 43 controls. Glucose, insulin, lipids, and blood pressure (BP) were measured following an overnight fast. Insulin resistance was estimated using homeostasis model assessment (HOMA). Metabolic syndrome was diagnosed according to National Cholesterol Education Program (NCEP) criteria. Subjects with OSA were more obese, had higher BP and fasting insulin, were more insulin resistant, had lower HDL cholesterol, and an increased incidence of metabolic syndrome (87% vs. 35%, p<0.0001). In order to determine whether these associations were independent of obesity and other known covariates, a regression analysis adjusted for age, BMI, smoking, and alcohol consumption was performed. This demonstrated that OSA was independently associated with increased systolic and diastolic blood pressure, higher fasting insulin and triglyceride concentrations, decreased HDL cholesterol, increased cholesterol:HDL ratio, and a trend towards higher HOMA values. Metabolic syndrome was 9.1 (95% confidence interval 2.6, 31.2: p<0.0001) times more likely to be present in subjects with OSA. CONCLUSIONS: OSA is independently associated with an increase in the cardiovascular risk factors that comprise the metabolic syndrome and its overall prevalence. This may help explain the increased cardiovascular morbidity and mortality associated with this condition.

Blood Glucose↗