Mortality in sleep apnea patients: a multivariate analysis of risk factors

Obstructive sleep apnea and cardiovascular disease

Obstructive sleep apnea (OSA) is a common medical condition that occurs in approximately 5% to 15% of the population. The pathophysiology of OSA is characterized by repetitive occlusions of the posterior pharynx during sleep that obstruct the airway, followed by oxyhemoglobin desaturation, persistent inspiratory efforts against the occluded airway, and termination by arousal from sleep. Obstructive sleep apnea is associated with daytime sleepiness and fatigue, likely due to fragmented sleep from recurrent arousals. Substantial evidence shows that patients with OSA have an increased incidence of hypertension compared with individuals without OSA and that OSA is a risk factor for the development of hypertension. Recent studies show that OSA may be implicated in stroke and transient ischemic attacks. Obstructive sleep apnea appears to be associated with coronary heart disease, heart failure, and cardiac arrhythmias. Pulmonary hypertension may be associated with OSA, especially in patients with preexisting pulmonary disease. Although the exact cause that links OSA with cardiovascular disease is unknown, there is evidence that OSA is associated with a group of proinflammatory and prothrombotic factors that have been identified to be important in the development of atherosclerosis. Obstructive sleep apnea is associated with increased daytime and nocturnal sympathetic activity. Autonomic abnormalities seen in patients with OSA include increased resting heart rate, decreased R-R interval variability, and increased blood pressure variability. Both atherosclerosis and OSA are associated with endothelial dysfunction, increased C-reactive protein, interleukin 6, fibrinogen, and plasminogen activator inhibitor, and reduced fibrinolytic activity. Obstructive sleep apnea has been associated with enhanced platelet activity and aggregation. Leukocyte adhesion and accumulation on endothelial cells are common in both OSA and atherosclerosis. Clinicians should be aware that OSA may be a risk factor for the development of cardiovascular disease.

Influence of sleep apnea on autonomic nervous activity and QT dispersion in patients with essential hypertension and old myocardial infarction

Sleep apnea syndrome (SAS) is an important cardiovascular risk factor in patients with hypertension or myocardial infarction (MI). We evaluated the influence of SAS on autonomic nervous activity and QT dispersion in patients with hypertension or coronary artery disease with old MI. A portable sleep polygraph was attached to 30 healthy volunteers (N group), 30 patients with essential hypertension (HT group), and 30 patients with old myocardial infarction (MI group) to serially record oronasal respiration, tracheal sound, thoracic respiratory movement, and percutaneous arterial oxygen saturation. In addition, a digital Holter ECG was used to examine heart rate variability during nighttime sleep. Heart rate variability was analyzed by obtaining low-frequency (LF) power, high-frequency (HF) power, the LF/HF ratio, and very low-frequency (VLF) power. Dispersion of QT intervals was obtained by CM5 and CM1 leads. VLF and LF powers were significantly higher in the HT-SAS group (hypertensive patients with SAS) than the N and HT-NSAS groups (hypertensive patients without SAS). The HF power was significantly lower in the HT-NSAS group than the N group, but the decrease in HF power in hypertension was not observed in the HT-SAS group. The LF/HF ratio was significantly higher in the HT-NSAS group than the N group, and this value was further increased in the HT-NSAS group. Percutaneous arterial oxygen saturation was decreased, and QT dispersion was significantly increased in the MI group during sleep apnea episodes. More severe autonomic nervous dysfunction and increased QTc dispersion were observed in hypertensive patients with SAS during episodes of apneas and hypopneas compared to those without SAS. These findings suggest that SAS may be associated with the future development of cardiac events.

Survival of veterans with sleep apnea: continuous positive airway pressure versus surgery

OBJECTIVES

Continuous positive airway pressure (CPAP) improves sleep apnea survival. We tested whether CPAP is associated with better survival than uvulopalatopharyngoplasty (UPPP).

STUDY DESIGN AND METHODS

This retrospective cohort database study included all sleep apnea patients treated with CPAP or UPPP in Veteran Affairs facilities from October 1997 through September 2001. Treatment groups were compared with Cox regression, adjusting for age, gender, race, year treatment was initiated, and comorbidity. Sleep apnea severity and CPAP use data were not available.

RESULTS

By September 2002, 1339 (7.1%) of 18,754 CPAP patients and 71 (3.4%) of 2,072 UPPP patients were dead (P < 0.001). After adjustment, CPAP patients had 31% (95% confidence interval, 3% to 67%, P = 0.03) higher probability of being dead at any time, relative to UPPP patients [corrected].

CONCLUSIONS

UPPP confers a survival advantage over CPAP, after adjustment for age, gender, race, year of treatment, and comorbidity. However, we were unable to adjust for sleep apnea severity or CPAP use. Surgical treatment should be considered in sleep apnea patients who use CPAP inadequately.

Sleep apnoea in the older adult : pathophysiology, epidemiology, consequences and management

Sleep apnoea is a breathing disorder in sleep usually caused by repetitive upper airway obstruction. Its primary symptoms include snoring, daytime sleepiness and decreased cognitive functioning. Risk factors for the condition include obesity, anatomical abnormalities, aging, and family history. It has been associated with hypertension, cardiovascular and pulmonary diseases and increased mortality. The prevalence of sleep apnoea increases with age, although the severity of the disorder, as well as the morbidity and mortality associated with it, may actually decrease in the elderly. A decline in cognitive functioning in older adults with sleep apnoea may resemble dementia. Medical management of sleep apnoea rarely relies on drug treatment, as the few drugs (antidepressants and respiratory stimulants) tested for treatment have been found to be ineffective, or cause tolerance or serious adverse effects and complications. The treatment of choice for sleep apnoea is continuous positive airway pressure, a device which generates positive air pressure through a nose mask, creating a splint which keeps the airway unobstructed throughout the night. Weight loss significantly decreases or eliminates apnoeas. Oral appliances are used to enlarge the airway at night by moving the tongue and mandible forward. Positional therapy involves avoiding the supine position during sleep in patients who mostly have apnoeas while lying on their back. Surgical management may also be considered, although with great caution in the elderly, because of their increased risk of complications related to surgery. Surgical procedures include nasal reconstruction, somnoplasty, laser-assisted uvuloplasty, uvulopalatopharyngoplasty, genioglossus advancement and hyoid myotomy, and maxillomandibular advancement for severe cases when other treatments have failed. As a last option, tracheostomy may be performed.

Hospital Use in the Treatment of Sleep Apnea

OBJECTIVES

Evaluate hospital use for treatment of sleep apnea.

STUDY DESIGN

Retrospective database review.

MATERIALS AND METHODS

The 1998 to 2000 National Inpatient Sample (NIS) was searched for admissions with a diagnosis of sleep apnea. Records were examined for demographics, diagnoses, procedures, and complications. Data were analyzed to identify factors affecting length of stay (LOS) and charges.

RESULTS

There were 5864 (0.03% NIS) admissions for sleep apnea. The sleep apnea group had lower mean age (43.1 vs. 47.2 years), higher percentages of males (71.6% vs. 41.0%) and African Americans (18.7% vs. 13.7%), and higher rates of obesity, hypertension, and anatomic airway diagnoses than the NIS population. Of sleep apnea group adults, 77.1% underwent a mean 2.3 procedures, whereas of those patients under 18 years of age, 60.8% underwent a mean of 1.2 procedures. Tracheotomy and procedures for hypopharyngeal airway compromise were used infrequently. Within the sleep apnea group, there were significant differences in LOS and charges on the basis of age, sex, race, payment method, procedures, and number of secondary diagnoses (all P <.05). Patients over 18 admitted for other diagnoses, but with secondary diagnosis of sleep apnea, had longer LOS (5.38 vs. 4.95 days) and higher charges (US dollars 16562 vs. US dollars 13928) than patients without sleep apnea.

CONCLUSIONS

Hospital use for sleep apnea remains largely for surgical treatment of the disease. Procedures directed at hypopharyngeal obstruction are seldom used. Multiple factors including patient age, number of secondary diagnoses, and procedures affect LOS and charges. The presence of sleep apnea also increases charges and LOS in patients admitted for other diagnoses.

Modafinil as adjunct therapy for daytime sleepiness in obstructive sleep apnea: a 12-week, open-label study

STUDY OBJECTIVES

The purpose of this 12-week study was to evaluate the efficacy and safety of adjunct modafinil to treat excessive sleepiness in patients with obstructive sleep apnea (OSA) who experience residual sleepiness despite regular nasal continuous positive airway pressure (nCPAP) use.

DESIGN

Twelve-week, open-label trial.

SETTING

Twenty-two centers in the United States.

PATIENTS

We studied 125 patients with moderate-to-severe OSA (ie, respiratory disturbance index > or =15) before nCPAP therapy and residual daytime sleepiness (Epworth sleepiness scale [ESS] score > or =10) despite effective and regular nCPAP therapy. Patients were studied after completing a 4-week, double-blind, placebo-controlled trial of nCPAP plus modafinil for the treatment of residual daytime sleepiness.

INTERVENTIONS AND MEASUREMENTS

Patients received individually titrated doses of modafinil (200 to 400 mg qd). Sleepiness was assessed using the ESS, quality of life was evaluated using the Functional Outcomes of Sleep Questionnaire (FOSQ), and the overall clinical effect was indexed using the clinical global impression of change scale. Adverse events, nCPAP use, and vital sign measurements were also recorded.

RESULTS

The significant improvements in daytime wakefulness and sleep-related functional status observed with modafinil treatment during the 4-week, double-blind study were maintained throughout 12 weeks of open-label treatment: week 12 ESS, 7.8 (4.7) vs 14.4 (3.1) at double-blind baseline; week 12 FOSQ, 3.3 (0.6) vs 14.4 (2.7) at double-blind baseline (mean [SD]). The percentage of patients rated as clinically improved increased from 83% after 1 week to > or =93% after 2 to 12 weeks of open-label treatment. Mean (SD) nCPAP use decreased from 6.3 (1.3) h/night at baseline to 5.9 (1.4) h/night (p = 0.004) during open-label treatment. The most common adverse events were headache (28%), anxiety (16%), and nervousness (14%).

CONCLUSIONS

Modafinil remained effective and well tolerated as an adjunct therapy for residual daytime sleepiness even after 12 weeks of daily dosing in patients with OSA receiving nCPAP therapy.

A comparison of public and private obstructive sleep apnea clinics

The aim of the present study was to compare the clinical findings and polysomnography results obtained at public and private clinics in Brazil, the follow-up after diagnosis, and the therapeutic aspects related to continuous positive airway pressure. Patients who snore and who have obstructive sleep apnea were retrospectively divided into two groups, i.e., public clinic (N=307) and private clinic (N=317). Data concerning age, sex, body mass index (BMI), neck circumference, medical history, sleepiness scale, follow-up after diagnosis, and acceptance of continuous positive airway pressure therapy were collected. Mean age was 50 +/- 12 (range: 15-80) for public patients and 48 +/- 12 years (range: 19-91) for private patients. Mean BMI was 30 +/- 6 (range: 19-67) for public patients and 31 +/- 6 kg/m (range: 21-59) for private patients. The public clinic had a significantly higher frequency of women than the private clinic (M:F ratio of 2.0:1 and 6.9:1, respectively). The condition of private patients (apnea-hypopnea index=31 +/- 25) was more severe than that of public patients (apnea-hypopnea index=25 +/- 24 events/h; P=0.0004). In the public and private clinics, 19 and 15% of patients were snorers, respectively, and 81 and 85% of them had sleep apnea. After diagnosis, follow-up was longer in the private group. The continuous positive airway pressure acceptance was similar for both groups (32 vs 35%), but patients from the public clinic abandoned treatment more than private ones (65 vs 13%). Social status was significant in terms of the severity of obstructive sleep apnea age and gender distribution. Private patients look for a diagnosis earlier in the course of the disease than public patients, adhere more to follow-up, and abandon continuous positive airway pressure treatment less than public patients do.

Metabolic disturbances in obesity versus sleep apnoea: the importance of visceral obesity and insulin resistance

Obstructive sleep apnoea (OSA) is a very prevalent disorder particularly amongst middle-aged, obese men, although its existence in women as well as in lean individuals is increasingly recognized. Despite the early recognition of the strong association between OSA and obesity, and OSA and cardiovascular problems, sleep apnoea has been treated as a 'local abnormality' of the respiratory track rather than as a 'systemic illness'. In 1997, we first reported that the pro-inflammatory cytokines interleukin (IL)-6 and tumour necrosis factor-alpha (TNF alpha) were elevated in patients with disorders of excessive daytime sleepiness (EDS) and proposed that these cytokines were mediators of daytime sleepiness. Also, we reported a positive correlation between IL-6 or TNF alpha plasma levels and the body mass index (BMI). In subsequent studies, we showed that IL-6, TNF alpha, leptin and insulin levels were elevated in sleep apnoea independently of obesity and that visceral fat, was the primary parameter linked with sleep apnoea. The association of OSA with insulin resistance and diabetes type 2 has been confirmed since then in several epidemiological and clinical studies. Furthermore, our findings that women with polycystic ovary syndrome (PCOS, a condition associated with hyperandrogenism and insulin resistance) were much more likely than controls to have sleep disordered breathing (SDB) and daytime sleepiness support the pathogenetic role of insulin resistance in OSA. Other findings that support the view that sleep apnoea and sleepiness may be manifestations of a serious metabolic disorder, namely the Metabolic or Visceral Obesity Syndrome, include: obesity without sleep apnoea is associated with daytime sleepiness; PCOS and diabetes type 2 are independently associated with EDS after controlling for SDB, obesity and age; and increased prevalence of sleep apnoea in postmenopausal women, with hormonal replacement therapy associated with a significantly reduced risk for OSA. In conclusion, accumulating evidence provides support to our model of the bi-directional, feedforward, pernicious association between sleep apnoea, sleepiness, inflammation and insulin resistance, all promoting atherosclerosis and cardiovascular disease.

Forced oscillation technique in the sleep apnoea/hypopnoea syndrome: identification of respiratory events and nasal continuous positive airway pressure titration

Sleep breathing disorders (SBD) are related to obstructions resulting from repetitive narrowing and closure of the pharyngeal airway. Their diagnoses and treatment are critically dependent on an accurate identification of and discrimination between types of respiratory events. However, these disorders have been diagnosed using indirect or invasive measurements, which resulted in serious doubts concerning the correct evaluation of breathing events. The forced oscillation technique (FOT) has recently been suggested as a clinical tool able to accurately and non-invasively quantify respiratory obstruction during sleep. The present study investigates the morphology of the impedance signal during different sleep respiratory events and evaluates the ability of impedance measurements in providing adequate nasal continuous positive airway pressure (nCPAP) titration. The results evidenced characteristic patterns in impedance signal morphology that are useful in the identification and classification of abnormal respiratory events. Moreover, significantly higher impedance values were obtained during apnoea and hypopnoea events when compared with normal values (p < 0.01). Studies using impedance measurements to adjust nCPAP showed a significant reduction (p < 0.01) of abnormal respiratory events, and a consequent normalization of the patients. These findings support the use of the FOT as a versatile clinic diagnostic tool helping SBD diagnosis and treatment.

Estudio de la validez de un equipo de poligrafía respiratoria (BREAS SC–20) para el diagnóstico del síndrome de apneas-hipopneas durante el sueño

OBJECTIVE

To validate the BREAS SC20 (Breas Medical AB, Mölnlyke, Sweden) polygraphic screening device, comparing it with conventional polysomnography (PSG), in the diagnosis of sleep apnea-hypopnea syndrome. A validity study of the diagnostic test was carried out at the sleep clinic of a tertiary hospital.

PATIENTS AND METHODS

Seventy patients clinically suspected of sleep apnea-hypopnea syndrome and treated at the sleep laboratory of the Hospital Txagorritxu, Vitoria, Spain, from November, 2001 until August, 2002 were consecutively enrolled in the study. Patient characteristics, comorbidities, and results on the Epworth sleepiness scale were recorded. The apneahypopnea index (AHI) per hour of sleep was determined by PSG; the respiratory events index (REI) per hour of screening was determined by the polygraphic screening device.

RESULTS

Sixty studies were valid (77% were men; mean [SD] age: 51.6 [13.2]; body mass index: 30.3 [5]; AHI: 31.0 [27.6]). The intraclass correlation coefficient between the AHI by PSG and the manual REI was 0.92. The mean difference between the AHI and the manual REI was 2.92 (9.75). The area under the receiver operating characteristic curve was 0.924 for the cut point AHI >or =5. The optimal cut point for an AHI > or = 5 was 3.6 in the REI (98% sensitivity). The respiratory screening device correctly classified 90% to 95% of the patients.

CONCLUSIONS

The BREAS SC20 is a valid system for identifying patients clinically suspected of sleep apnea-hypopnea syndrome.

[Diagnosis and treatment of obstructive sleep apnea-hypopnea syndrome: the situation in Navarra (Spain)]

OBJECTIVE

To assess the diagnosis and treatment of obstructive sleep apnea-hypopnea syndrome (OSAHS) in Navarra (Spain) and to know the characteristics of patients treated with nasal continuous positive airway pressure (n-CPAP) in our community.

METHOD

All patients receiving nasal n-CPAP from the public health service of Navarra in July 2000 were enrolled. A nurse visited each patient and filled in a form with epidemiological data, and patient and clinical characteristics. The nurse then measured CO in expired air and the n-CPAP pressure used and recorded the hour counter reading on the n-CPAP device. Between one and two months later and without prior warning, the patient was once again contacted and a second visit was made. The counter was read again and expired CO was measured.

RESULTS

The prevalence of treatment with n-CPAP in Navarra was 125/100,000 inhabitants, and a gradual increase in annual prescriptions was observed. Home visits were made to 535 patients (80.7% of the total). Pneumologists wrote 83.5% of the prescriptions. n-CPAP was used a mean 6.1 hours/day, and the numbers of declared and real hours of use were statistically correlated. The mean apnea-hypopnea index was 51.5, although results were not available for 4.2% of the patients. The treatment was well tolerated according to 83.7% of the patients and 24.8% had been following it for over four years. The pathology most often associated with OSAHS was obesity (73.4% of the patients), followed by high blood pressure (40%); 299 patients (55.8%) had two or more associated diseases and 54 (9.7%) had none. Conventional polysomnography was the diagnostic method used in 45.9% of the cases, and respiratory polygraphs were available for 49.7%. Pressure was adjusted with the aid of polysomnography for 19.4% patients, whereas 32.1% had undergone no testing. Side effects of treatment were reported by 50.8%.

CONCLUSIONS

a) The prevalence of n-CPAP treatment in Navarra is high and prescriptions are increasing; b) patient tolerance of and compliance with therapy are good, c) polysomnographs or respiratory polygraphs are available for diagnosis of OSAHS in most cases but the n-CPAP pressure level is adjusted without the recommended studies for many patients.

Obstructive sleep apnoea

Obstructive sleep apnoea is a disease of increasing importance because of its neurocognitive and cardiovascular sequelae. Abnormalities in the anatomy of the pharynx, the physiology of the upper airway muscle dilator, and the stability of ventilatory control are important causes of repetitive pharyngeal collapse during sleep. Obstructive sleep apnoea can be diagnosed on the basis of characteristic history (snoring, daytime sleepiness) and physical examination (increased neck circumference), but overnight polysomnography is needed to confirm presence of the disorder. Repetitive pharyngeal collapse causes recurrent arousals from sleep, leading to sleepiness and increased risk of motor vehicle and occupational accidents. The surges in hypoxaemia, hypercapnia, and catecholamine associated with this disorder have now been implicated in development of hypertension, but the association between obstructive sleep apnoea and myocardial infarction, stroke, and congestive heart failure is not proven. Continuous positive airway pressure, the treatment of choice for obstructive sleep apnoea, reduces sleepiness and improves hypertension.

Prevalence of sleep apnoea and snoring in hypertensive men: a population based study

BACKGROUND

Several studies have reported an association between sleep disordered breathing (SDB) and hypertension (HT) but there is still a debate as to whether this is an effect of confounders. Some researchers have found an age dependent relationship between SDB and HT with higher risk at lower ages. A case-control study was performed in hypertensive men and non-hypertensive male controls matched for age and body mass index to assess whether there is an independent association between SDB and HT. If so, we further wanted to investigate whether this effect is age dependent.

METHODS

An overnight sleep study was performed in a population based, age stratified sample of 102 hypertensive men aged 43-82 years and 102 non-hypertensive controls.

RESULTS

Hypertensive subjects had a significantly higher prevalence of SDB than non-hypertensive subjects (apnoea-hypopnoea index (AHI): 10.8 v 7.3; desaturation index (DI): 8.5 v 5.2; AHI >or=10: 37% v 24%, p<0.05; DI >or=10: 29% v 12%; lowest desaturation: mean (SD) 81.9 (7.3) v 84.7 (6.1), p<0.01). After adjusting for neck circumference and physical inactivity, DI >or=10 and lowest desaturation were still independent predictors of HT with adjusted odds ratios of 2.3 (95% CI 1.0 to 5.3) and 0.94 (95% CI 0.89 to 0.99), respectively. When the subjects were split into two groups according to age (<60 and >or=60 years), the influence of DI >or=10 on HT was strongest in the younger men (adjusted OR 4.3 (95% CI 1.0 to 19.3 v 2.1 (95% CI 0.7 to 6.5)) and the association between minimum oxygen saturation (SaO(2)) and HT reached statistical significance in the younger men only.

CONCLUSION

SDB is more prevalent in men with HT than in controls. DI >or=10 and lowest desaturation are independent predictors of HT irrespective of confounders. The results indicate that the influence of SDB on HT is more pronounced in younger and middle aged men than in those above 60 years.

Obstructive sleep apnea: a comparison of black and white subjects

OBJECTIVE

To determine if the severity of obstructive sleep apnea syndrome (OSA) differs by racial group.

STUDY DESIGN

Cross-sectional retrospective review.

SETTING

University-based sleep disorders laboratory.

METHODS

The study reviewed the results of 280 adult (>18 y) patients diagnosed with obstructive sleep apnea syndrome by overnight polysomnogram between July 1, 1999, and June 30, 2000. Factors analyzed included age, sex, race, presence of hypertension, body mass index (kg/m2), respiratory disturbance index (RDI), and lowest oxygen saturation level.

RESULTS

Blacks with OSA are significantly more obese and have significantly higher rates of hypertension than white subjects with OSA. Black females with OSA are significantly younger than white females at the time of diagnosis (P =.005). Black males with OSA have significantly lower oxygen saturations than white males (P =.025).

CONCLUSION

Black males who present to the otolaryngologist-head and neck surgeon for evaluation of sleep-disordered breathing may be at increased risk of severe OSA.

Plasma vascular endothelial growth factor in sleep apnea syndrome: effects of nasal continuous positive air pressure treatment

Sleep apnea syndrome is associated with recurrent episodic hypoxia during sleep, which has been implicated in the development of cardiovascular morbidity. Hypoxia is the major stimulus of vascular endothelial growth factor (VEGF), which is a potent angiogenic cytokine. In the present article we describe the results of three experiments in which plasma concentrations of VEGF were measured in patients with sleep apnea. In Experiment 1, apnea-hypopnea index was found to be a significant independent predictor of morning VEGF concentrations in 85 male subjects investigated in the sleep laboratory, of whom 47 had an apnea-hypopnea index greater than 20. In Experiment 2, VEGF concentrations measured hourly during the sleep period were found to be significantly higher in a group of five sleep apnea patients compared with six age-similar snorers and six normal young adults (129.1 +/- 43.4 versus 74.6 +/- 11.5 and 32.5 +/- 12.8 pg/ml, respectively [p < 0.007]). In Experiment 3, VEGF concentrations were compared in patients with sleep apnea before and 1 year after nasal continuous positive airway pressure treatment. A significant decrease in VEGF concentrations was found only in patients in whom nocturnal hypoxia improved after treatment (57.1 +/- 62.5 versus 39.6 +/- 46.9 pg/ml, p < 0.01). There was no comparable improvement in patients who did not accept treatment (53.9 +/- 23.6 versus 54.0 +/- 21.5 pg/ml, ns). These results raise the possibility that VEGF may contribute to the long-term adaptation of sleep apnea syndrome to recurrent nocturnal hypoxia.

Characteristics of sleep apnea syndrome in tetraplegic patients

OBJECTIVE

To include a larger number of tetraplegics than in previous studies, in order to more reliably characterize the pathogenesis and predisposing factors of sleep apnea in tetraplegia.

METHODS

Sleep breathing data and oxymetric values were investigated in 50 randomly selected tetraplegic patients and discussed in context with age, gender, BMI, neck circumference, type and height of lesion, time after injury, spirometric values and medication. A non-validated short questionnaire on daytime complaints was added.

RESULTS

Thirty-one patients out of 50 had an RDI > or =15, defined as sleep disordered breathing (SDB); 24 of them combined with an apnea index of 5 or more, these cases were diagnosed as sleep apnea syndrome (SAS). SAS was apparent in 55% and 20% of the studied men and women, respectively. Regression analyses showed no significant correlation between RDI and lesion level, ASIA impairment scale or spirometric values. In contrast, a significant correlation between RDI and age, BMI, neck circumference and time after injury could be shown. Kruskal-Wallis test for dichotomous non-parametric factors, such as gender, cardiac medication and daytime complaints, showed significant differences with regard to RDI. In contrast to able-bodied people with SAS, daytime complaints were only present in tetraplegic patients with severe pathology (RDI>40).

CONCLUSION

Incidence of SAS is high in tetraplegia, particularly in older male patients with large neck circumference, long standing spinal cord injury and under cardiac medication. As tetraplegics with RDI between 15 and 40 reported no daytime complaints and often have normal BMI, these tetraplegics are not clinically suspicious for SAS. The increased use of cardiac medication in tetraplegics with SAS may implicate a link between SAS and cardiovascular morbidity, one of the leading causes of death in tetraplegia.

Increased physician-reported sleep apnea: the National Ambulatory Medical Care Survey

BACKGROUND

Despite increased recognition of sleep apnea as a major health problem, little is known about physician practice patterns regarding this condition.

METHODS

We used the National Ambulatory Medical Care Survey (NAMCS) data between the years of 1990 to 1998, a weighted estimate of the frequency of physicians' diagnoses nationwide in their outpatient practices, to address the following questions: (1) has there been an increase in physician reporting of sleep apnea, (2) which physicians reported diagnoses of sleep apnea, and (3) what are the demographic characteristics of patients with diagnoses of sleep apnea?

RESULTS

During this 9-year period, there was a 12-fold increase in the diagnosis of sleep apnea in outpatients, from 108,121 to 1,305,624 diagnoses (p < 0.001). Among other primary sleep disorders, only insomnia had an increase in reporting (fourfold, p < 0.001). Report of sleep apnea was greatest among primary care providers (37%), pulmonologists (24%), and otolaryngologists (18%). Sleep apnea was reported more often in men than in women (3:1, respectively), and 80% of diagnoses occurred in the following age groups: 30 to 39 years (12%), 40 to 49 years (33%), 50 to 59 years (27%), and 60 to 69 years (12%). Conditions associated with sleep apnea included hypertension (10%), obesity (6%), and COPD (7%). Increased reporting of sleep apnea by NAMCS physicians was associated with increases in the number of accredited sleep laboratories and the number of sleep publications in the medical literature during the period of review (p < 0.001).

CONCLUSION

Sleep apnea is recognized increasingly by physicians. Further investigation is necessary to define those factors that influence physician recognition and reporting of sleep apnea, and approaches associated with optimum patient outcomes.

Long-term follow-up of untreated patients with sleep apnoea syndrome

Obstructive sleep apnoea (OSA) is a common disorder with numerous potential sequelae. Although the majority of these consequences can be reduced with appropriate treatment, only limited data exist regarding the natural progression ofthis disorder in untreated individuals. We hereby report a long-term follow-up of all untreated patients (n = 40) followed-up in the Technion Sleep Clinic, using both subjective and objective measurements. In addition, we report a long-term follow-up of 11 patients who attempted dietary weight loss. The average time interval between the first and second polysomnographies for the untreated group was 5.0 +/- 2.8 yrs, and 2.5 +/- 2.3 yrs for the weight reduction group. There was no significant change in Body Mass Index (BMI) or Respiratory Disturbance Index (RDI) between the two Polysomnographic (PSG) evaluations in the untreated patients. However, eight patients developed hypertension (n=5) or ischaemic heart disease (IHD) (n=3) between the two evaluations. RDI, age and BMI at the time ofthe initial evaluation were not predictive of changes in RDI, snoring intensity or minimal oxygen saturation. However, the patients who developed hypertension/IHD had significantly higher RDI than the patients who did not (46 +/- 27 vs. 23 +/- 17 h(-1), P < 0.005). In the weight-loss group, BMI decreased by a mean of 3.1 kg m(-2), and RDI decreased by 20events h(-1), P<0.05 for both. There was a significant correlation between the weight loss and improvement in RDI (R = 0.75, P = 0.005). We conclude that in untreated obstructive sleep apnoea patients RDI does not necessarily increase over time, but associated hypertension or ischaemic heart disease may develop. When weight loss is successfully achieved, sleep apnoea significantly improves with a high correlation between the extent of weight loss and the improvement in apnoea status.

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.

Mortality in Obstructive Sleep Apnea: Association with Impaired Wakefulness

Sleep fragmentation from obstructive sleep apnea (OSA) is correlated with a shortened sleep latency on the Maintenance of Wakefulness Test (MWT) and the Multiple Sleep Latency Test. Whether impairment of wakefulness is associated with increased mortality in OSA patients is unknown. We evaluated survival over an average timespan of 7.5 years from the date of diagnosis in a consecutive series of 322 OSA patients who had undergone nocturnal polysomnograpy and the MWT. Evaluable survival data were obtained in 142 patients. Twenty two had died. Deaths were predominantly due to cardiovascular disease. A comparison of the demographic and sleep study data between the alive and dead groups was significant for differences in MWT sleep latency and in age at time of diagnosis. The MWT mean sleep latency, when adjusted for age, was significantly shortened in the dead patients (28 +/- 11 min vs. 21 +/- 10 min, p < 0.005). Also, there was a significant decrease in survival in the patients whose MWT mean sleep latency was less than 20 min. These findings demonstrate an association between impairment of wakefulness and long-term mortality in OSA patients. This association was not evident for the other measures used to assess OSA severity.

4-year follow-up of treatment with dental appliance or uvulopalatopharyngoplasty in patients with obstructive sleep apnea: a randomized study

STUDY OBJECTIVES

To evaluate the effects of treatment with a dental appliance or uvulopalatopharyngoplasty (UPPP) on somnographic variables in patients with mild-to-moderate obstructive sleep apnea (OSA) followed up for 4 years, and compliance and complementary treatment.

DESIGN

Randomized study.

SETTING

Central Hospital, Västerås, Uppsala University, Sweden.

PATIENTS

Ninety-five male patients with confirmed mild-to-moderate OSA (apnea index [AI] > 5 and < 25) were randomized to treatment with a dental appliance or UPPP. Sleep studies were performed before and 1 year and 4 years after intervention. Thirty-two patients in the dental-appliance group and 40 patients in the UPPP group completed the 4-year follow-up.

RESULTS

The success rate (percentage of patients with at least 50% reduction in AI) in the dental-appliance group was 81%, which was significantly higher than in the UPPP group, 53% (p < 0.05). Normalization (AI < 5 or apnea/hypopnea index < 10) was observed in 63% of the dental-appliance group and 33% of the UPPP group after 4 years. The difference between the groups was significant (p < 0.05). The compliance to use of the dental appliance was 62% at the 4-year follow-up. Thirty patients (75%) in the UPPP group continued without complementary treatment. The dental appliances had few adverse effects on the stomatognathic system, and the number of adjustments and repairs of the appliances over time was moderate. Pronounced complaints of nasopharyngeal regurgitation of fluid and difficulty with swallowing after UPPP were reported by 8% and 10%, respectively.

CONCLUSIONS

The dental-appliance group showed significantly higher success and normalization rates regarding the somnographic variables compared to the UPPP group, but the effectiveness of the dental appliance was partly invalidated by the compliance of 62% at the 4-year follow-up. However, the appliances had few adverse effects on the stomatognathic system and required only moderate adjustments. Use of a dental appliance with regular follow-up can be recommended for long-term treatment of OSA.

Snoring as a risk factor for type II diabetes mellitus: a prospective study

To examine the association between snoring and risk of developing type II diabetes mellitus, the authors analyzed data from the Nurses' Health Study cohort. This analysis included 69,852 US female nurses aged 40-65 years without diagnosed diabetes, cardiovascular disease, or cancer at baseline in 1986. Snoring patterns were ascertained by questionnaire. During 10 years of follow-up, 1,957 women were diagnosed with type II diabetes. In analyses adjusted for age and body mass index, snoring was associated with risk of diabetes (for occasional snoring vs. nonsnoring, relative risk (RR) = 1.48 (95% confidence interval (CI): 1.29, 1.70); for regular snoring vs. nonsnoring, RR = 2.25 (95% CI: 1.91, 2.66); p for trend < 0.0001). Further adjustment for other diabetes risk factors and sleeping-related covariates only slightly attenuated the risk (for occasional snoring, RR = 1.41 (95% CI: 1.22, 1.63); for regular snoring, RR = 2.03 (95% CI: 1.71, 2.40); p for trend < 0.0001). Analyses stratified by body mass index, smoking history, or parental history of diabetes showed a consistent association between snoring and diabetes within the categories of these variables. These results suggest that snoring is independently associated with elevated risk of type II diabetes.

Should all sleep apnoea patients be treated? Yes

Obstructive sleep apnoea (OSA) is a common condition. Whether an apnoeic patient should be considered for treatment depends on the definition of the syndrome, the rating of the severity and the potential morbidity associated with this condition. We have reviewed several types of evidence that early treatments of OSA deserved. There is a natural evolution of OSA leading to spontaneous aggravation and an increased cardiovascular morbidity in untreated patients in clinical populations. Excessive daytime sleepiness (EDS), the key symptom of the disease, can be found with very low apnoea hypopnoea index (AHI) and eliminated by adequate treatment. Cardiovascular risks are present with very low AHI and there is a high relative risk of developing hypertension in the future when patients present with mild OSA at baseline. The effect of treatment is significant when compared with placebo in the mildest forms of the disease. The clinical benefit, however, is mainly expected in terms of consequences for behavioural morbidity (i.e. reversibility of EDS and its related consequences) as the impact on cardiovascular morbidity is more doubtful and may anyway not be observed on a short-term follow-up. Overall, any OSA syndrome that is clearly responsible for EDS should be considered for treatment. Moreover, there is increasing evidence that the cardiovascular risk has to be taken into account when deciding on treatment, even in asymptomatic patients. All this evidence put together suggests early treatment in OSA.

Sleep and brain lesions: a critical review of the literature and additional new cases

We present a comprehensive review of sleep studies performed in patients with brain lesions complemented by 16 additional personal selected cases and by discussion of the corresponding animal data. The reader is cautioned about the risk of establishing an erroneous correlation between abnormal sleep and a given disorder due to the important inter and intra variability of sleep parameters among individuals. Salient points are stressed: the high frequency of post-stroke sleep breathing disorders is becoming increasingly recognised and may, in the near future, change the way this condition is managed. Meso-diencephalic bilateral infarcts induce a variable degree of damage to both waking and non-REM sleep networks producing and abnormal waking and sometimes a stage 1 hypersomnia reduced by modafinil or bromocriptine, which can be considered as a syndrome of cathecholaminergic deficiency. Central pontine lesions induce REM and non-REM sleep insomnia with bilateral lateral gaze paralysis. Bulbar stroke leads to frequent sleep breathing disorders. Polysomnography can help define the extent of involvement of various degenerative diseases. Fragmented sleep in Parkinson's disease may be preceded by REM sleep behavioural disorders. Multiple system atrophies are characterised by important sleep disorganization. Sleep waking disorganization and a specific ocular REM pattern are often seen in supra-nuclear ophtalmoplegia. In Alzheimer patients, sleep perturbations parallel the mental deterioration and are possibly related to cholinergic deficiency. Fronto-temporal dementia may be associated with an important decrease in REM sleep. Few narcoleptic syndromes are reported to be associated with a tumour of the third ventricle or a multiple sclerosis or to follow a brain trauma; all these cases raise the question whether this is a simple coincidence, a revelation of a latent narcolepsy or, as in non-DR16/DQ5 patients, a genuine symptomatic narcolepsy. Trypanosomiasis and the abnormal prion protein precociously after sleep patterns. Polysomnography is a precious tool for evaluating brain function provided it is realised under optimal conditions in stable patients and interpreted with caution. Several unpublished cases are presented: one case of pseudohypersomnia due to a bilateral thalamic infarct and corrected by modafinil, four probable late-onset autosomal recessive cerebellar ataxias without sleep pattern anomalies, six cases of fronto-temporal dementia with strong reduction in total sleep time and REMS percentage on the first polysomnographic night, one case of periodic hypersomnia associated with a Rathke's cleft cyst and four cases of suspected symptomatic narcolepsy with a DR16-DQ5 haplotype, three of which were post-traumatic without MRI anomalies, and one associated with multiple sclerosis exhibiting pontine hyper signals on MRI.

Sleep-disordered breathing and coronary artery disease: long-term prognosis

The evidence linking sleep-disordered breathing to increased mortality and cardiovascular morbidity has been conflicting and inconclusive. We hypothesized that a potential adverse effect of disordered breathing would be more obvious in patients with established vascular disease. In a prospective cohort study 408 patients aged 70 yr or younger with verified coronary disease were followed for a median period of 5.1 yr. An apnea-hypopnea index (AHI) of > or = 10 and an oxygen desaturation index (ODI) of > or = 5 were used as the diagnostic criteria for sleep-disordered breathing. The primary end point was a composite of death, cerebrovascular events, and myocardial infarction. There was a 70% relative increase and a 10.7% absolute increase in the primary composite end point in patients with disordered breathing defined as an ODI of > or = 5 (risk ratio 1.70, 95% confidence interval [CI] 1.15-2.52, p = 0.008). Similarly, patients with an AHI of > or = 10 had a 62% relative increase and a 10.1% absolute increase in the composite endpoint (risk ratio 1.62, 95% CI 1.09-2.41, p = 0.017). An ODI of > or = 5 and an AHI of > or = 10 were both independently associated with cerebrovascular events (hazard ratio 2.62, 95% CI 1.26-5.46, p = 0.01, and hazard ratio 2.98, 95% CI 1.43-6.20, p = 0.004, respectively). We conclude that sleep-disordered breathing in patients with coronary artery disease is associated with a worse long-term prognosis and has an independent association with cerebrovascular events.

Modafinil as adjunct therapy for daytime sleepiness in obstructive sleep apnea

Patients with obstructive sleep apnea/hypopnea syndrome can experience residual daytime sleepiness despite regular use of nasal continuous positive airway pressure therapy. This randomized, double-blind, placebo-controlled, parallel group study assessed the efficacy and safety of modafinil for the treatment of residual daytime sleepiness in such patients. Patients received modafinil (n = 77) (200 mg/d, Week 1; 400 mg/d, Weeks 2 to 4) or matching placebo (n = 80) once daily for 4 wk. Modafinil significantly improved daytime sleepiness, with significantly greater mean changes from baseline in Epworth Sleepiness Scale scores at Weeks 1 and 4 (p < 0.001) and in multiple sleep latency times (MSLT) at Week 4 (p < 0.05). The percentage of patients with normalized daytime sleepiness (Epworth score < 10) was significantly higher with modafinil (51%) than with placebo (27%) (p < 0.01), but not for MSLT (> 10 min; 29% versus 25%). Headache (modafinil, 23%; placebo, 11%; p = 0.044) and nervousness (modafinil, 12%; placebo, 3%; p = 0.024) were the most common adverse events. During modafinil or placebo treatment, the mean duration of nCPAP use was 6.2 h/night, with no significant change from baseline observed between groups. Modafinil may be a useful adjunct treatment for the management of residual daytime sleepiness in patients with obstructive sleep apnea/hypopnea syndrome who are regular users of nasal continuous positive airway pressure therapy.

Long-term follow-up of sleep disordered breathing in older adults

OBJECTIVE

The current study was designed to determine whether, with increasing age, sleep apnea improves, becomes worse, or stays the same.

BACKGROUND

There is a high prevalence of sleep disordered breathing (SDB) in older adults, but little is known about longitudinal changes. This study followed older adults to examine the natural history of SDB.

METHODS

Subjects were randomly selected community-dwelling elderly (n=427). A subset of subjects was studied approximately every 2 years over an 18-year period. Overnight sleep recordings and sleep questionnaires were completed at each time point.

RESULTS

Multiple linear regression showed that three variables were associated with change in respiratory disturbance index (RDI):body mass index (BMI) at initial visit (P=0.001), change in BMI (P=0.02), and a consistent self-report of high blood pressure (P=0.005). RDI increase was associated with BMI increase and presence of self-reported high blood pressure.

CONCLUSIONS

The changes in RDI that occurred were associated only with changes in BMI and were independent of age. This underscores the importance of managing weight for older adults, particularly those with hypertension.

Age-related changes in upper airway muscles morphological and oxidative properties

Obstructive sleep apnea (OSA) is a common disorder of the middle aged and elderly. It results from the decrease in upper airway muscle (UAM) tone that occurs during sleep. It is unclear whether age-related changes in UAM could constitute a contributory mechanism to the increased prevalence of OSA with increasing age, and previous papers evaluating the effects of aging on UAM in rats reported conflicting results. In the present study, we compared, in four age groups of Wistar rats (6-24 months), fiber-type distribution, mean cross-sectional fiber area and succinate dehydrogenase optical density of dilating and non-dilating UAM, and the diaphragm. Succinate dehydrogenase optical density, a marker of oxidative capacity, decreased significantly after the age of 6 months in all muscles (except for the sternohyoid), particularly in the genioglossus, the main tongue protrudor. In this muscle, we also found a significant decrease in type IIa and an increase in IIb fibers after the age of 18 months. Age-related changes in fiber-type distribution in other muscles were mostly insignificant. Dilating UAM could not be distinguished from their non-dilating neighboring muscles by their histochemical properties or aging-related changes. The aging-related changes observed in the present study may decrease UAM endurance, particularly that of the main tongue protrudor, the genioglossus.

Plasma homocysteine levels in obstructive sleep apnea: association with cardiovascular morbidity

OBJECTIVES

Obstructive sleep apnea (OSA) is associated with cardiovascular morbidity and mortality. Plasma levels of homocysteine are also associated with cardiovascular morbidity and mortality. We therefore investigated homocysteine and conventional cardiovascular risk factors in OSA patients with and without cardiovascular morbidity in comparison with normal control subjects and ischemic heart disease (IHD) patients without OSA.

SETTING

Technion Sleep Medicine Center, Haifa, Israel.

METHODS AND PARTICIPANTS

Levels of homocysteine, cholesterol, low-density lipoprotein, high-density lipoprotein, triglycerides, creatinine, vitamins B(12) and B(6), and folic acid were determined in 345 participants after overnight fasting. These included OSA patients with IHD (n = 49), with hypertension (n = 61), or without any cardiovascular disease (n = 127). Two control groups were employed: IHD patients without or with low likelihood for sleep apnea (n = 35), and healthy control subjects (n = 73).

RESULTS

After adjustment for age, body mass index, creatinine, and existence of diabetes mellitus, OSA patients with IHD had significantly higher homocysteine levels (14.6 +/- 6.77 micromol/L) than all other groups including the IHD-only patients. Hypertensive OSA patients had comparable homocysteine levels to IHD patients (11.80 +/- 5.28 micromol/L and 11.92 +/- 5.7 micromol/L, respectively), while patients with OSA only had comparable levels to normal control subjects (9.85 +/- 2.99 micromol/L and 9.78 +/- 3.49 micromol/L, respectively). No differences in conventional cardiovascular risk factors or in vitamin levels were found between groups.

CONCLUSIONS

Patients with the combination of IHD and OSA have elevated homocysteine levels. We hypothesize that these results may be explained by endothelial dysfunction combined with excess free-radical formation in OSA patients.

Obstructive sleep apnea and hypertension: from correlative to causative relationship

Sleep-disordered breathing, manifested by repetitive episodes of partial or complete cessation of breathing during sleep associated with brief arousal and autonomic activation, is estimated to affect as many as 4% of adult men and 2% of adult women. Studies conducted during the 1980s revealed a strong association between sleep-disordered breathing and hypertension. The results of these early studies, which relied on relatively small samples of patients, have been confirmed in recent years by large-scale epidemiologic studies that are controlled for all possible confounding factors. This paper reviews the evidence suggesting a causative relationship between hypertension and disordered breathing in sleep. The authors discuss the possible underlying mechanisms of the two entities and address the clinical implications of this relationship. They conclude by recommending a proactive approach to the diagnosis of breathing disorders in sleep, in order to prevent the cardiovascular sequelae of this syndrome.

Obstructive sleep apnea-hypopnea and related clinical features in a population-based sample of subjects aged 30 to 70 yr

The prevalence and related clinical features of obstructive sleep apnea-hypopnea (OSAH) in the general population were estimated in a two-phase cross-sectional study. The first phase, completed by 2,148 subjects (76.9%), included a home survey, blood pressure, and a portable respiratory recording, whereas in the second, subjects with suspected OSAH (n = 442) and a subgroup of those with normal results (n = 305) were invited to undergo polysomnography (555 accepted). Habitual snoring was found in 35% of the population and breathing pauses in 6%. Both features occurred more frequently in men, showed a trend to increase with age, and were significantly associated with OSAH. Daytime hypersomnolence occurred in 18% of the subjects and was not associated with OSAH. An apnea-hypopnea index (AHI) > or = 10 was found in 19% of men and 15% of women. The prevalence of OSAH (AHI > or = 5) increased with age in both sexes, with an odds ratio (OR) of 2.2 for each 10-yr increase. AHI was associated with hypertension after adjusting for age, sex, body mass index, neck circumference, alcohol use, and smoking habit. This study adds evidence for a link between OSAH and hypertension.

Anaesthesia and sleep apnoea

Sleep disordered breathing is a common problem affecting all age groups, particularly in association with certain other medical conditions and syndromes. The pathological consequences of the disorder may be severe, with significant implications for the perioperative management of sufferers. Research into the effects of surgery and anaesthesia on sleep is very much in its infancy. Understanding of the implications of sleep disturbance and sleep disordered breathing for perioperative morbidity and mortality is limited. While several observations have led to considerable speculation in the literature, evidence of a causal relationship is still largely lacking. Anaesthetists are ideally placed to screen large numbers of people for sleep disordered breathing, a source of considerable community morbidity. Recognizing the symptoms, signs and associations of the condition during the preoperative visit is important in planning management, as is recognition of the likelihood of OSA in patients who present difficulty with tracheal intubation or airway maintenance. Particular care is required in the perioperative management of patients with diagnosed or suspected sleep apnoea.

Sleep Disorders in the Elderly

Sleep disturbances in the elderly may not be a result of the aging process per se, but rather are likely caused by many factors that are amenable to treatment. These factors include medical and psychiatric problems, medications, and circadian rhythm changes, all of which can cause difficulties during sleep at night, and can lead to complaints of insomnia. Other factors that cause disturbances include a high prevalence of specific sleep disorders such as sleep disordered breathing (SDB), periodic limb movements during sleep (PLMS) and rapid eye movement (REM) sleep behavior disorder (RBD). Although these disorders are more prevalent in the older than younger population, they are not exclusive to this age group, and treatment options that are applicable to young adults are also applicable to older adults. On the other hand, dementia and Parkinson's disease are two neurologic disorders that are almost exclusive to the elderly and most often involve sleep disturbances. Because there are many causes of sleep complaints, when considering treatment options one must identify the underlying problem. If caused by illness, effective treatment of a specific medical or psychiatric problem should help alleviate the sleep problem as well. Changes in the timing of drug administration may improve sleep. For the treatment of chronic insomnia, behavior techniques should always be used in combination with pharmacologic therapy, and sedative-hypnotic medications should be considered when appropriate. The treatment of choice for obstructive sleep apnea is continuous positive airway pressure (CPAP). For PLMS, dopaminergic agents are most effective. For RBD, clonazepam effectively controls the aversive sleep behaviors. Sleep disturbances secondary to dementia and Parkinson's disease are usually problematic for the patient as well as the caregiver, whether in the home or in the nursing home. Proper management of these disturbances is beneficial in terms of delaying institutionalization and reducing nursing care costs, as well as improving the quality of life for both patient and caregiver.

Sleep apnea syndrome in chronic spinal cord injury: associated factors and treatment

OBJECTIVE

To determine the prevalence of sleep apnea in a sample of persons with chronic spinal cord injury (SCI) of varying injury levels and degrees of impairment.

DESIGN

Cross-sectional study.

SETTING

Inpatient SCI rehabilitation unit.

PARTICIPANTS

Twenty men with SCI (motor complete and incomplete; American Spinal Injury Association classes A-D) of at least 1 year's duration, randomly selected from patients with SCI undergoing elective hospitalization.

MAIN OUTCOME MEASURES

Apnea index, determined by sleep study (including chest wall movement, airflow, oxygen saturation), and daytime sleepiness, determined by Epworth sleepiness score.

RESULTS

Eight subjects (40%) had sleep apnea, manifested by elevated apnea index (mean +/- SD, 17.1 +/- 6.9) and excessive daytime sleepiness. Sleep apnea was commonly diagnosed in motor-incomplete injuries. A trend (p = .07) existed toward a greater prevalence of sleep apnea with tetraplegia. Age and body mass index were not associated with sleep apnea.

CONCLUSION

The prevalence of sleep apnea in men with chronic SCI admitted for nonrespiratory elective hospitalization is high relative to the general population.

CLINICAL REVIEW ARTICLE: Epidemiology of sleep-related obstructive breathing

The diagnosis of obstructive sleep apnoea syndrome (OSAS) and upper airway resistance syndrome (UARS) is based both on a combination of laboratory findings from whole-night sleep recordings and daytime symptoms. Due to the recent interest in breathing disturbances during sleep many prevalence studies have been performed within this field. There are, however, methodological difficulties in characterizing these syndromes in large populations; many of the studies have therefore been unable to present an overview of the complete syndromes but rather have focused on specific characteristics. In epidemiological research snoring and/or daytime sleepiness have often been used as markers of OSAS, while other studies have looked only on the respiratory disturbances or oxygen desaturation. Studies on the prevalence of OSAS based on polysomnography are reviewed here, as well as investigations where associated factors such as cardiovascular diseases and mortality were analysed. The interrelationships between snoring, daytime symptoms and laboratory findings are discussed. Gender, age, obesity, smoking, alcohol and ethnicity are all factors that influence the prevalence of OSAS. The data on associations between OSAS and cardiovascular disease or mortality are sometimes unrelated. Much of the discrepancy between different studies can be explained by the methodological difficulties connected with the definition of OSAS and also by the fact that the association between sleep-disordered breathing and cardiovascular outcome seems to be age-dependent.

Assessment and treatment of sleep disturbances in older adults

Sleep disturbances are common in older adults. These disturbances are often secondary to medical illness and/or medication use or are due to specific problems such as sleep disordered breathing, periodic limb movements in sleep and circadian rhythm disturbances. The prevalence of sleep disordered breathing and periodic limb movement in sleep increases with age. The circadian rhythm tends to advance with age, causing older people to awaken early in the morning. Insomnia is often caused by pain associated with medical illness. Insomnia can also be caused by stimulating medications. In institutionalized elderly, sleep becomes even more disturbed and fragmented than in community-dwelling older adults. Accurate assessment and diagnosis is crucial since effective treatment strategies are available for these sleep disturbances. The effect, prevalence and treatment of each of these conditions is reviewed.

The role of habitual snoring and obesity in the development of diabetes: a 10-year follow-up study in a male population

OBJECTIVES

There are many similarities between diabetes (mainly type 2) and sleep breathing disturbances regarding risk factors, anthropometric criteria and consequences of morbidity and mortality. The aim of this study was to investigate whether the association between habitual snoring and diabetes is entirely dependent on obesity.

DESIGN

A population-based prospective study.

SETTING

The municipality of Uppsala, Sweden.

SUBJECTS AND METHODS

In 1984 and in 1994, 2668 men aged 30-69 years at baseline answered questionnaires concerning sleep breathing disturbances and somatic diseases.

RESULTS

Of those with habitual snoring in 1984, 5.4% reported that they had developed diabetes during the 10-year period compared with 2.4% of those without habitual snoring (P < 0.001). Amongst obese snorers, 13.5% developed diabetes compared with 8.6% of obese non-snorers (P = 0.17). In a multiple logistic regression model, the odds ratio (95% confidence interval) for development of diabetes was higher in obese snorers [7.0 (2.9-16.9)] than in obese non-snorers [5.1 (2.7-9.5)] after adjustment for age, weight gain, smoking, alcohol dependence and physical inactivity.

CONCLUSIONS

We conclude that, in males aged 30-69 years, habitual snoring is associated with an increased incidence of diabetes within 10 years. Although obesity is the main risk factor for developing diabetes, coexistent habitual snoring may add to this hazard.

Treating obstructive sleep apnea and snoring: assessment of an anterior mandibular positioning device

BACKGROUND

Dental devices have been used to help manage snoring and obstructive sleep apnea, or OSA. This article reports on patients' compliance with and complications of long-term use of an anterior mandibular positioning, or AMP, device.

METHODS

The device used was a custom-made, two-piece, full-coverage, adjustable acrylic appliance, connected with Herbst attachments. The appliance was used nightly and advanced the mandible by 75 percent of the patient's maximum protrusive distance. Patients were telephoned to determine whether they were still using the AMP device. If not, they were asked when and why they stopped using it. The study sample included 65 consecutive patients with mild-to-moderate obstructive sleep apnea and snoring.

RESULTS

Long-term use (three years or more) of the AMP device in these patients was 51 percent (27 of 53 patients). Of the 53 responding patients, 40 percent reported jaw/facial muscle pain, 40 percent had occlusal changes, 38 percent reported tooth pain, 30 percent reported jaw joint pain and 30 percent experienced xerostomia. Of the 27 long-term AMP users, 22 rated themselves as being very satisfied and four as somewhat satisfied; one was neither satisfied nor dissatisfied with the appliance.

CONCLUSIONS

It was determined that with use of the AMP device, 40 percent of patients will develop some minor complications of jaw, mouth and/or tooth pain, and approximately 26 percent of long-term users might experience a painless but irreversible change in their occlusion. Annual follow-up office visits with the dentist appear necessary for early detection of these changes.

CLINICAL IMPLICATIONS

Patients with mild-to-moderate OSA who receive a two-piece, adjustable AMP device should be informed that 50 percent of patients quit using the device in a three-year period and some will experience shifts in their occlusion.

Reported snoring--does validity differ by age?

Snoring is a major sign of obstructive sleep apnoea syndrome. Despite the frequent number of studies based on subjective reports of snoring, self-reported snoring has hardly been validated at all. In some previous epidemiological studies, a significant association between snoring and cardiovascular morbidity and mortality was found only below the age of 50-60 y. This study was performed to investigate whether this is due to a decrease in the validity of reported snoring with increasing age. In a population-based study, 2668 men aged 40-79 y answered a questionnaire including questions on snoring. Those who reported loud and disturbing snoring often or very often were regarded as habitual snorers. Without taking account of reported snoring, an age-stratified sample of these men was selected and their snoring was measured using a microphone for 1 night. Significant snoring was defined as recorded snoring sounds for >/= 10% of the night. The participants were divided into younger (age 40-59, mean +/- SD: 51.8 +/- 4.6 y, n=132) and older (age 60-79, 67.7 +/- 5.4 y, n=99) age groups. When analysing the validity of reported snoring, no significant differences were found between the younger and older age groups in terms of specificity [younger: 82% (95% CI 74-90%), older: 88% (81-95%)] or sensitivity [younger: 40% (26-54%), older: 35% (17-53%)]. These data indicate that, in men aged 40-79 y, the validity of reported snoring is similar in different age groups. The lack of an association between reported snoring and cardiovascular disease at higher ages can, therefore, not be explained by a decrease in the validity of reported snoring.

Sleep-related breathing disorder is an independent risk factor for uncontrolled hypertension

OBJECTIVE

To test the hypothesis that sleep-related breathing disorder (SRBD) is associated with poor blood pressure control in hypertensive patients independent from confounding factors such as age, body mass index, alcohol, smoking and daytime blood gases.

DESIGN AND METHODS

This cross-sectional study of a sleep laboratory cohort was carried out at the University Hospital Sleep Disorders Centre, Marburg. The study comprised 599 patients referred for a sleep study, all of them with a documented history of systemic hypertension and/or previously initiated antihypertensive therapy. Data were obtained from a clinical interview, two unattended sleep studies and assessment of clinic blood pressure, cholesterol level, alcohol and nicotine consumption and daytime blood gases. The main outcome measure was a post hoc analysis of predictors for poor blood pressure control.

RESULTS

Respiratory disturbance index (RDI) was significantly higher in patients with uncontrolled hypertension (blood pressure > or = 160 and/or 95 mmHg, n = 463) than in those with controlled hypertension (n = 136) (34.0 +/- 26.8 versus 27.0 +/- 23.5, P < 0.01). The relative proportion of patients with uncontrolled hypertension increased significantly as SRBD activity increased (chi2, P< 0.05). Body mass index was the only independent predictor (P = 0.006) of uncontrolled hypertension in the whole study sample. However, in the subset of patients aged < or = 50 years, RDI (P= 0.006) and age (P = 0.016) were the only independent predictors. The probability of uncontrolled hypertension increased by approximately 2% (B = 0.019, P= 0.006) for each RDI unit.

CONCLUSION

SRBD should be considered, in addition to traditional confounders, as a risk factor for poor blood pressure control in younger hypertensive patients (< or = 50 years of age).