Increased incidence of nonfatal cardiovascular events in stroke patients with sleep apnoea: effect of CPAP treatment

Obstructive sleep apnoea (OSA) is a risk factor for stroke, but little is known about the effect of OSA and continuous positive airway pressure (CPAP) on the incidence of long-term, nonfatal cardiovascular events (CVE) in stroke patients. A prospective observational study was made in 223 patients consecutively admitted for stroke. A sleep study was performed on 166 of them. 31 had an apnoea/hypopnoea index (AHI) <10 events · h(-1); 39 had an AHI between 10 and 19 events · h(-1) and 96 had an AHI ≥ 20 events · h(-1). CPAP treatment was offered when AHI was ≥ 20 events · h(-1). Patients were followed up for 7 yrs and incident CVE data were recorded. The mean ± SD age of the subjects was 73.3 ± 11 yrs; mean AHI was 26 ± 16.7 events · h(-1). Patients with moderate-to-severe OSA who could not tolerate CPAP (AHI ≥ 20 events · h(-1); n = 68) showed an increased adjusted incidence of nonfatal CVE, especially new ischaemic strokes (hazard ratio 2.87, 95% CI 1.11-7.71; p = 0.03), compared with patients with moderate-to-severe OSA who tolerated CPAP (n = 28), patients with mild disease (AHI 10-19 events · h(-1); n = 36) and patients without OSA (AHI <10 events · h(-1); n = 31). Our results suggest that the presence of moderate-to-severe OSA is associated with an increased long-term incidence of nonfatal CVE in stroke patients and that CPAP reduces the excess of incidence seen in these patients.     

The impact of ageing and sex on the association between sleepiness and sleep disordered breathing

The aim of our study was to investigate age-related changes in sleepiness symptoms associated with sleep disordered breathing (SDB). Wisconsin Sleep Cohort participants were assessed using polysomnography, the Epworth Sleepiness Scale (ESS) and the multiple sleep latency test (MSLT). SDB was defined as an apnoea/hypopnoea index ≥15 events·h(-1), and sleepiness as ESS ≥10 and MSLT ≤5 min. Odds ratios were calculated using generalised estimating equations associating sleepiness with SDB, and conditional logistic regression examining changes in longitudinal sleepiness status (ESS only). Models were a priori stratified by sex. ESS was measured in 1,281 participants and MSLT in 998 at multiple time-points (ESS n=3,695; MSLT n=1,846). Significant interactions were found between SDB and age in males, but not females. The odds ratios modelled for sleepiness in a 40-yr-old male with SDB were significant compared to a male without SDB (ESS 2.1 and MSLT 2.9); however, these associations were not significant at 60 yrs of age. The within-subject odds ratio for sleepiness was also significant at 40 yrs of age (OR 3.4), but not at 60 yrs of age. The age-related reductions in the association between sleepiness and SDB may have clinical implications for the diagnosis and treatment of SDB in older people as sleepiness is often used as a therapeutic target.     

Pulmonary vascular resistances during exercise in normal subjects: a systematic review

The physiological range of pulmonary vascular resistance (PVR) and total pulmonary resistance (TPR), and the impact of exercise, age and posture have been a matter of debate for many years. We performed a systematic literature review including all right heart catheterisation data where individual PVR and TPR of healthy subjects both at rest and exercise were available. Data were stratified according to age, exercise level and posture. Supine resting PVR in subjects aged <24 yrs, 24-50 yrs, 51-69 yrs and ≥70 yrs was 61±23, 69±28, 86±15 and 90±39 dyn·s·cm(-5), respectively. Corresponding TPR was 165±50, 164±46, 226±64 and 223±45 dyn·s·cm(-5), respectively. During moderate exercise in subjects aged ≤50 yrs, an 85% increase in cardiac output was associated with a 25% decrease in TPR (p<0.0001) and a 12% decrease in PVR (p<0.01). At 51-69 yrs of age there was no significant decrease in TPR and PVR. In individuals aged ≥70 yrs TPR even increased by 17% (p=0.01), while PVR did not change significantly. At higher exercise levels, TPR decreased in all age groups. In the upright position, based on a limited number of data, resting TPR and PVR were higher than in the supine position and decreased more prominently during exercise, suggesting the release of resting pulmonary vasoconstriction. These data may form a basis to define normal PVR at rest and exercise.     

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.     

Sleep-disordered breathing in acromegalics--relation of hormonal levels and quantitative sleep study by means of bedside oximeter

Sleep-disordered breathing (SDB) is common in patients with growth hormone (GH) secreting pituitary adenomas. Since long-term untreated SDB aggravates systemic conditions (hypertension and arrhythmia etc.), the therapeutic outcome of SDB is important in reducing morbidity and mortality rates. But the results of a quantitative analysis of the lowered GH and IGF-1 levels in SDB in a relatively large number of patients are not detailed. Ten consecutive acromegalic patients were studied with a bedside oximeter. Preoperatively they were divided into two groups based on the presence (SDB group = 6 patients) or absence (non-SDB group = 4 patients) of clinical symptoms of SDB such as habitual snoring, excessive daytime somnolence and nocturnal apneic episodes. The serum IGF-1 averaged 931.7 ng/ml in SDB group and 898.3 ng/ml in non-SDB group. The oxygen desaturation index (ODI) (the number of oxygen desaturations exceeding 4% from the base line) was 29.1+/-15.4 in the SDB group and 2.5+/-1.8 in the non-SDB group (P=0.01). Other oximeter parameters such as the percent of the time spent at O2 saturation < 90% and the mean and the lowest O2 saturations closely correlated with the degree of the clinical symptoms. A postoperative sleep study was conducted in 5 patients in the preoperative SDB group, 4 months or more after the surgery. The serum GH and IGF-1 levels normalized in 3 patients but remained slightly high in 2. ODI became 9.1+/-5.6, which was significantly lower than the preoperative value (P=0.026). One patient had a complete clinical resolution. The other 4 obtained slight to moderate improvement clinically and oximetrically despite normalized or decreased hormonal levels. This study clarified that the response of SDB to lowering of the GH level varies from one patient to another and persisting SDB despite the normalization of the hormonal levels suggests the involvement of other factors in the production of SDB.     

Detection of postoperative sleep-disordered breathing using a portable monitoring device

Purpose

Adverse surgical outcomes may occur more frequently in patients with sleep-disordered breathing (SDB). Despite this concern, there have been no prospective studies using objective measures of postoperative SDB to determine the scope of the problem. We designed a prospective study to determine the feasibility of identifying SDB in elective postoperative patients by the use of a type IV portable monitor (PM).

Methods

Patients >18?years old who presented for elective surgery with at least one postoperative hospital night on a non-monitored unit were enrolled and wore a type IV device that measured nasal flow, heart rate, and oxygen saturation on their first postoperative night. Respiratory disturbance index (RDI) and oxygen desaturation index (ODI) were generated for each patient.

Results

Data sufficient for interpretation were collected on 100/116 patients enrolled. SDB (RDI ??5) was observed in 51% of the study group, and 17% had a RDI >15. An elevated ODI ??5 was seen in 42%, while 17% had an ODI ??15. Device malfunction occurred in 16% of the study participants.

Conclusion

A type IV PM can be employed in the postoperative setting to detect and gauge the severity of SDB.     

Follow-up assessment of CPAP efficacy in patients with obstructive sleep apnea using an ambulatory device based on peripheral arterial tonometry

This study aimed to assess the accuracy of a wrist-worn device based on peripheral arterial tonometry (Watch_PAT 100) to detect residual episodes of respiratory disturbance during continuous positive airway pressure (CPAP) therapy. Concurrent polysomnography was used as the reference standard to identify sleep disordered breathing (SDB) events. The study was conducted in three sleep laboratories affiliated with tertiary care academic medical centers. Seventy patients using CPAP to treat obstructive sleep apnea for at least 3 months, following an in-laboratory titration to determine the optimal therapeutic positive airway pressure, participated in this study. Symptoms indicating suboptimal therapy were not required for participation, but self-reported adherence to CPAP therapy was necessary for inclusion. Interventions are not applicable in this study. The accuracy of the PAT-derived respiratory disturbance index (PAT RDI scored by automated algorithm) to detect residual SDB on CPAP was assessed against polysomnography (PSG) using Bland–Altman analysis, receiver–operator characteristic (ROC) curves, and likelihood ratios for increasing (LR+) and decreasing (LR−) the probability of moderate–severe SDB in the study population. Respiratory events on the PSG were quantified using standard criteria for research investigations (“Chicago criteria”) to yield a PSG RDI.C. Based on the PSG results, 19% of the participants had moderate–severe SDB (PSG RDI.C>15 events per hour) on their prescribed pressure. For PAT RDI >15 events per hour, the area under the ROC curve was 0.95 (SE 0.03, p<0.0001, 95% CI 0.89 to 1.00), the LR+ was 8.04 (95% CI 3.64–17.7), and the LR− was 0.17 (95% CI 0.05–0.62). The mean difference between the PAT RDI and PSG RDI.C was three (2SD 14.5) events per hour. Therefore, residual moderate–severe SDB on CPAP was not uncommon in a multicenter population self-reporting adherence to CPAP therapy to treat obstructive sleep apnea. The Watch_PAT device accurately identified participants with moderate–severe SDB while using CPAP in the attended setting of a sleep laboratory.     

Prevalence of snoring and sleep-disordered breathing in a student population

INTRODUCTION: The prevalence of snoring and sleep-disordered breathing (SDB) in young adults in Southeast Asian countries is unknown. We aim to determine the symptoms and prevalence of SDB in a university student population using a questionnaire survey followed by home sleep monitoring. METHODS: The Sleep and Health Questionnaire (a modified version of the Specialized Centers of Research Sleep Questionnaire, translated into Chinese) was distributed to all first-year students (1,306 male and 1,757 female) enrolled in the Chinese University of Hong Kong. Subsequently, those students who returned the questionnaires were randomly chosen to undergo portable home sleep monitoring using the MESAM IV device (Madaus Medizin-Elektronik; Freiburg, Germany). RESULTS: A total of 1,910 replies were obtained from 3,063 questionnaires sent by mail (response rate, 62.4%). The female to male ratio was 1.8:1, with mean age of 19.4 years (SD, 1.3 years) and mean body mass index (BMI) of 20.0 (SD, 2.5). Overall, 25.7% of subjects reported snoring; 10.7% and 42.1% reported impaired performance ability and daytime sleepiness, respectively. Of the 88 subjects who underwent overnight sleep monitoring, 66 subjects (75%) were snorers and 8 subjects (9%) snored > 10% of the night. Male subjects had a higher BMI (p < 0.001) and tended to snore more often than female subjects (p = 0.06). Subjects with an oxygen desaturation index (ODI) > or = 3 had a BMI > 22 (p < 0.05). On sleep study, nine subjects (10.2%) and two subjects (2.3%) had a respiratory disturbance index (RDI) > or = 3 and an RDI > or = 5, respectively, associated with self-reported sleepiness, giving a minimum estimated prevalence of SDB as 0.1% (RDI > or = 5) in the study population. There was no correlation between recorded snoring with either RDI or self-reported sleepiness. Questionnaire responses, neck circumference, and alcohol consumption did not predict the occurrence of SDB. CONCLUSION: Snoring was prevalent, while SDB was uncommon in this student population. However, snoring and self-reported symptoms by questionnaire were poor predictors for SDB. Male gender showed a trend as an independent predictor for snoring, but not for SDB.     

Prevalence of snoring and sleep-disordered breathing in a group of commercial bus drivers in Hong Kong

Objectives: To assess the prevalence of sleep‐­disordered breathing (SDB) and its associated symptoms in a group of commercial bus drivers in Hong Kong. Methods: Two hundred and sixteen of 410 bus drivers from three different shifts were interviewed with the Sleep & Health Questionnaire (SHQ) and the Epworth sleepiness scale (ESS) at a Hong Kong bus depot. Seventeen subjects from each shift were then randomly selected for at‐home sleep study using the Mesam IV device (Madaus Medizin?Elektronik, Freiburg, Germany). Results: There were 207 men and nine women (mean age 42.4 ± 7.5 years; body mass index (BMI) 25.4 ± 4.5 kg/m²; ESS 5.3 ± 4.2). From the SHQ it was discovered that: (i) daytime sleepiness was reported by 87 subjects (40%), (ii) snoring ≥ 3 times per week was reported by 80 subjects (37%), (iii) witnessed apnoea was reported by 17 subjects (7.9%) and (iv) 29 subjects (13.4%) reported having fallen asleep during driving. Among the 51 subjects who underwent the at‐home sleep study: (i) 31 subjects (61%) had respiratory disturbance index (RDI) ≥ 5 per hour of sleep, (ii) 21 subjects (41%) had RDI ≥ 10 per hour of sleep, (iii) 12 subjects (24%) had RDI ≥ 15 per hour of sleep and (iv) 35 subjects (68.6%) snored objectively ≥ 10% of the night. Ten subjects (20%) had RDI ≥ 5 and sleepiness at work, while five subjects (9.8%) had RDI ≥ 5 and ESS > 10. No significant differences were noted in the SHQ responses, ESS, objective snoring or RDI among the three groups. Multiple regression analysis showed that BMI and witnessed apnoea were the only positive independent predictors of RDI. Conclusions: This study showed a high prevalence of objective snoring and SDB in a group of commercial bus drivers. Neither self‐reported sleepiness nor the ESS could identify subjects with SDB. (Intern Med J 2002; 32: 149?157)     

Echocardiographic features of the right heart in sleep-disordered breathing: the Framingham Heart Study

The effect of sleep-disordered breathing (SDB) on right heart structure and function is controversial. Studies of patients referred for evaluation of possible sleep apnea have yielded conflicting results, and the impact of SDB on the right heart has not been investigated in the general population. We examined the echocardiographic features of subjects with SDB at the Framingham Heart Study site of the Sleep Heart Health Study. Of 1,001 polysomnography subjects, 90 with SDB defined as a respiratory disturbance index (RDI) score > 90th percentile (mean RDI = 42) were compared with 90 low-RDI subjects (mean RDI = 5) matched for age, sex, and body mass index. Right heart measurements, made without knowledge of clinical status, were compared between groups. The majority of the subjects were male (74%). After multivariable adjustment, right ventricle (RV) wall thickness was significantly greater (p = 0.005) in subjects with SDB (0.78 +/- 0.02 cm) than in the low-RDI subjects (0.68 +/- 0.02 cm). Right atrial dimensions, RV dimensions, and RV systolic function were not found to be significantly different between subjects with SDB and the low-RDI subjects. We conclude that in this community-based study of SDB and right heart echocardiographic features, RV wall thickness was increased in subjects with SDB. Whether the RV hypertrophy observed in persons with SDB is associated with increased morbidity and mortality remains unknown.     

At 68 years, unrecognised sleep apnoea is associated with elevated ambulatory blood pressure

After the age of 65 yrs the specific impact of unrecognised sleep-related breathing disorders (SRBD) on 24-h blood pressure (BP) levels remains under debate. We tested the cross-sectional relationship between the severity of obstructive sleep apnoea/hypopnoea (OSAH) and the increase of BP using ambulatory BP monitoring (ABPM) in the PROOF (PROgnostic indicator OF cardiovascular and cerebrovascular events study)-SYNAPSE (Autonomic Nervous System Activity, Aging and Sleep Apnea/Hypopnea study) cohort. 470 subjects (aged 68 yrs) neither treated for hypertension nor diagnosed for SRBD were included. All subjects underwent ABPM, and unattended at-home polygraphic studies. OSAH was defined by an apnoea/hypopnoea index (AHI) >15·h(-1). The severity of the sleep apnoea was also quantified as the index of dips in oxyhaemoglobin saturation >3% (ODI). Results are expressed in per protocol analysis. Severe OSAH (AHI >30·h(-1), 17% of subjects) was associated with a significant 5 mmHg increase in both diurnal and nocturnal systolic BP (SBP), and with a nocturnal 3 mmHg increase in diastolic BP (DBP). Systolic (mean SBP >135 mmHg) or diastolic (mean DBP >80 mmHg) hypertension were more frequently encountered in subjects suffering from moderate (AHI 15-30) or severe OSAH. After adjustment, the independent association between severe OSAH and 24-h systolic hypertension remained significant (OR 2.42, 95% CI 1.1-5.4). The relationship was further reinforced when SRBD severity was expressed using ODI >10·h(-1). The impact of unrecognised SRBD on BP levels also exists at the age of 68 yrs. The hypoxaemic load appears to be the pathophysiological cornerstone for such a relationship.     

Sleep apnea syndrome in patients with cardiac pacemaker

BACKGROUND: Heart rhythm disturbances are cardiac side effects in patients with sleep-disordered breathing (SDB), which in itself is considered to be a risk factor for bradycardic rhythm disturbances. OBJECTIVE: We analyzed the prevalence and degree of SDB in patients who received a cardiac pacemaker due to bradycardic rhythm disturbances and investigated the relationship between the severity of an underlying SDB and the type of heart rhythm disturbance. METHODS AND RESULTS: 192 patients (100 males, 92 females, mean age 62.2 +/-12.2 years) were studied using the portable screening device MESAM IV. The respiratory disturbance index (RDI) was calculated visually. The mean RDI in all patients was 9.13+/-11. 09/h, 11.7+/-13.15/h in males and 6.33+/-7.42/h in females. The prevalence ratio of SDB between men and women was 1.7:1, with significant differences in the respective severity (p<0.05). The screening showed a prevalence of SDB (RDI >10/h) of 32.3%. The highest prevalence was found in the group of patients with atrial fibrillation and bradycardia. However, there were no significant differences compared to other types of rhythm disturbances. The RDI in the population studied depended on age and body mass index, but not on the existence or type of rhythm disturbance and not on concomitant diseases. CONCLUSION: The prevalence of SDB in cardiac pacemaker patients is similar to that in patients of comparable age without a pacemaker. A heart rhythm disturbance does not seem to be an independent risk factor for development of SDB. Nevertheless, the differential diagnosis of bradycardic rhythm disturbances in this age group should include a screening for sleep apnea.     

The influence of renal insufficiency on sleep-disordered breathing in patients with symptomatic chronic heart failure

BACKGROUND:

Renal insufficiency, a common condition among patients with chronic heart failure, complicates the management of heart failure. However, the influence of renal insufficiency on sleep-disordered breathing (SDB) – another important comorbidity of heart failure – has not been well studied.

METHODS:

Seventy-nine patients (60 men and 19 women) with stable, symptomatic heart failure caused by left ventricular systolic dysfunction (left ventricular ejection fraction of less than 45%) were studied.

RESULTS:

Thirty-nine patients (49%) had SDB as defined by an apnea-hypopnea index (AHI) of five or greater: 15 patients were classified as having mild SDB (AHI of five or greater and less than 15), 10 patients as having moderate SDB (AHI of 15 or greater and less than 30) and 14 patients as having severe SDB (AHI of 30 or greater). The etiology of SDB was predominantly central. Plasma brain natriuretic peptide concentration in the severe SDB group was 587±377 pg/mL, which was significantly higher than those of the remaining three groups (P<0.05). On the other hand, estimated glomerular filtration rate (eGFR) was comparable between non-SDB and SDB groups. There was no statistically significant correlation between eGFR and AHI, or between eGFR and the number of central sleep apneas in the study patients.

CONCLUSION:

Higher plasma brain natriuretic peptide concentrations were associated with more severe SDB, whereas the level of eGFR was not correlated with the severity of SDB. The results suggest that renal dysfunction plays a relatively minor role in determining breathing abnormalities in chronic heart failure.     

Effects of olmesartan on blood pressure and insulin resistance in hypertensive patients with sleep-disordered breathing

The increased risk of cardiovascular morbidity and mortality among patients with sleep-disordered breathing (SDB) has been linked to arterial hypertension and insulin resistance. However, an effective antihypertensive agent for patients with SDB has not been identified. We investigated the effect of the angiotensin II subtype 1 receptor blocker olmesartan in hypertensive patients with SDB. This prospective, one-arm pilot study included 25 male patients with untreated SDB (mean age, 52.7 ± 11.4 years). We measured blood pressure, oxygen desaturation index (ODI), cardiac function using echocardiography, and insulin resistance using the homeostasis model assessment (HOMA) before and after 12 weeks of olmesartan therapy (mean dose, 17.6 ± 4.4 mg/day). Olmesartan significantly decreased systolic blood pressure (151.4 ± 8.0 vs. 134.0 ± 7.4 mmHg; P < 0.001), diastolic blood pressure (93.4 ± 7.1 vs. 83.9 ± 6.3 mmHg; P < 0.001), and HOMA index (3.7 ± 2.9 vs. 2.8 ± 1.9; P = 0.012). Furthermore, left ventricular ejection fraction significantly increased at 12 weeks (68.1 ± 5.1 vs. 71.6 ± 5.4%; P = 0.009). However, body mass index (BMI) and degree of SDB did not change (BMI, 26.6 ± 4.0 vs. 26.6 ± 4.2 kg/m2, P = 0.129; 3% ODI, 29.5 ± 23.1 vs. 28.2 ± 21.0 events/h, P = 0.394). Olmesartan significantly reduced blood pressure and insulin resistance in hypertensive patients with SDB without changing BMI or SDB severity.     

Classification of sleep-disordered breathing

Increasing recognition of sleep-disordered breathing (SDB) and its morbidity have prompted reevaluation of techniques to identify respiratory events during sleep. The present study was designed to evaluate the utility of various metrics of SDB and to identify the optimal respiratory metric that objectively correlates to symptoms of excessive daytime somnolence (EDS). Metrics were derived from combinations of conventional apnea/hypopnea, flow limitation events (transient elevated upper airway resistance identified by characteristic flattening on the flow/time tracing, using a noninvasive nasal cannula technique), desaturation, and arousal. A total of 137 subjects underwent clinical evaluation and nocturnal polysomnogram. In 34 randomly selected subjects, the best metrics for discriminating between 13 subjects with no EDS/snoring and 21 patients with EDS and snoring were identified by receiver operator curve analysis. Of the metrics and cut points tested, a total respiratory disturbance index (RDI(Total), sum of apneas, hypopnea, and flow limitation events) of 18 events/h was found to have the best discriminant ability (100% sensitivity and 96% specificity). Prospective testing of this metric was then performed with the remaining 103 subjects (14 nonsnoring non-EDS, 21 snoring non-EDS, 68 snoring with EDS). Using this cutoff of 18 events/h, we obtained 71% sensitivity and 60% specificity for identifying subjects with EDS. We conclude that, in subjects with upper airway dysfunction, an index that incorporates all respiratory events provides the best quantitative physiological correlate to EDS.     

Sleep disordered breathing and cognitive function in a retirement village population.

Sleep disordered breathing (SDB) may be associated with cognitive dysfunction in non-demented elderly people. A random sample of 96 retirement village residents were given both neuropsychological assessment and overnight sleep monitoring with a portable microprocessor based system (Vitalog PMS-8). Respiratory disturbance index (RDI) was calculated as the number of apnoeas and hypopnoeas per hour of sleep. RDI was not associated with 'memory', 'verbal', and 'motor' factors identified from the analysis of cognitive tests, but was associated with the 'cerebral efficiency' factor (R2 = 0.21, p less than 0.0001). Seventy-three subjects had repeat neuropsychological tests, median time to follow-up being 17 months. Baseline RDI did not predict changes in scores on the two factors identified from the second analysis. We conclude that mild to moderate disturbance of breathing during sleep is not associated with cognitive dysfunction in non-demented subjects.     

11O例老年阻塞性睡眠呼吸暂停低通气综合征患者多导睡眠监测及相关分析

目的 加深对老年患者阻塞性睡眠呼吸暂停低通气综合征(obstructive sleep apneahypopnea syndrome,OSAHS)特点的认识,提高老年OSAHS诊治水平.方法 对我院睡眠呼吸障碍与鼾症诊治中心诊断的110例老年OSAHS患者的整夜多导睡眠图(PSG)监测资料进行回顾性分析,应用SPSS 18.0统计软件对患者的一般情况、睡眠结构、呼吸暂停和低通气情况、氧减饱和情况以及各指标间可能的相关关系进行统计分析.结果老年OSAHS患者中位快动眼相(rapid eye movement,REM)和非快动眼相(NREM)睡眠时间分别占2.17%和76.73%;中位觉醒指数为45.60次/h.呼吸暂停最长时间为(51.94±22.06)s,中位呼吸暂停平均时间为22.50 s,低通气最长时间为(47.06±12.52)s,低通气平均时间为(21.50±4.63)s.中位呼吸紊乱指数(respiratory disturbance index,RD1)为21.50,RDI 5～20者占46.40%,20～40者占31.80%,＞40者占21.80%.夜间平均血氧饱和度为(93.45±2.81)%,夜间最低血氧饱和度为(76.30±10.50)%,中位氧减饱和指数为31.65次/h.体质指数(BMI)与夜间最低血氧饱和度(r=-0.378,P＜0.01)和夜间平均血氧饱和度(r=-0.355,P＜0.01)呈负相关,与氧减指数呈正相关(r=0.338,P＜0.01);夜间最低血氧饱和度与阻塞性呼吸暂停最长时间(r=-0.47,P＜0.01)、阻塞性呼吸暂停平均时间(r=-0.31 6,P＜0.01)、低通气最长时间(r=-0.293,P＜0.01)和低通气平均时间(r=-0.277,P＜0.01)呈负相关.仰卧位睡眠时中位氧减时间间隔为2.36 min,左侧卧位睡眠时中位氧减时间间隔为11.54 min,右侧卧位睡眠时中位氧减时间间隔为12.45 min,左侧卧位和右侧卧位睡眠时中位氧减时间间隔均长于仰卧位(Z值分别为-6.12和-7.10,均P＜0.01).结论 老年OSAHS患者存在明显的睡眠结构紊乱和睡眠片段化.依据RDI对患者的病情分级,大多数OSAHS患者为轻、中度,但缺氧程度较重,缺氧严重度与BMI和睡眠呼吸事件的持续时间相关,侧卧睡眠时缺氧程度减轻.     

Effects of sex on sleep-disordered breathing in adolescents.

This study was conducted to determine the influence of puberty on features of sleep-disordered breathing (SDB) in adolescents. The study was performed in a general population sample of 226 adolescents of both sexes (aged 11-19 yrs) recruited from the secondary school population of the city of Seville, Spain. Subjects were divided into two groups: 1) postpubertal, i.e. females who had undergone menarche and males in whom axillary hair development or peak height velocity had occurred > 1 yr before the study; and 2) peripubertal, i.e. females who had not undergone menarche and males who had not developed axillary hair nor reached peak height velocity, or subjects in whom these pubertal changes had appeared < 1 yr before the study. All subjects answered a questionnaire on SDB and underwent overnight cardiorespiratory polygraphy. There were 50 males and 40 females (mean +/- SD age 13.5 +/- 1.2 yrs) in the peripubertal group, and 54 males and 82 females (age 16.3 +/- 1.7 yrs) in the postpubertal group. Males exhibited significantly higher neck circumference/height index and waist/hip index than females in both the peripubertal and postpubertal groups. In the postpubertal group, snoring and polygraphic alterations (respiratory events and oximetric parameters) were significantly more frequent in males than in females. Postpubertal adolescents showed sex differences in clinical and polygraphic parameters that were not observed at earlier pubertal stages. These findings support the influence of sex hormones on sex differences in sleep-disordered breathing.     

新诊断2型糖尿病患者葡萄糖耐量试验与糖化血红蛋白水平的相关分析

目的 对比分析新诊断2型糖尿病及糖尿病前期患者口服葡萄糖耐量试验(OGTT)与糖化血红蛋白(HbAIc)水平变化的特点及影响因素. 方法 按照OGTT结果将受检者分为糖耐量正常组(正常组):31例,年龄29～75岁,平均(48.4±15.3)岁;空腹血糖受损组(血糖受损组):33例.年龄38～72岁,平均(50.8±9.8)岁;糖耐量受损组:34例,年龄33～74岁,平均(54.5±11.4)岁;2型糖尿病组(T2DM组):117例,年龄29～75岁,平均(54.3±14.1)岁.采用OGTT试验、HbAlc结果评价糖代谢状态,胰岛β细胞功能指数(HOMA-E)、OGTT 30 min胰岛素分泌增值与血糖增值比值(△I30/△G330)、胰岛素分泌曲线下面积(AUCINS)及胰岛素抵抗指数(HOMA-IR)分别反映胰岛β细胞分泌功能和胰岛素抵抗情况. 结果 (1)T2DM、糖耐量受损组和正常组HbAlc分别为7.41%、5.85%和5.21%,差异有统计学意义(P<0.01),T2DM、糖耐量受损组和血糖受损组HOMA-β指数与正常组比较,分别下降了53.1%(P<0.01)、29.3%(P<0.01)和23.4%(P<0.05),T2DM组HOMA-IR分别是正常组的1.66倍(P<0.01)、血糖受损组的1.29倍(P<0.001)和糖耐量受损组的1.44倍(P<0.05);(2)HbAIc与糖负荷后3 h血糖水平相关性最高(r=0.71,P<0.01),且独立相关;△I30/△G330与糖负荷后1 h和2 h血糖水平独立负相关(P<0.01);AUCINS只与糖负荷后3 h血糖水平独立负相关(P<0.01);HOMA-β与2 h以外的其他各点血糖独立负相关(P<0.01);HOMA-IR与OGTT各点血糖水平均呈正相关(P<0.01或P<0.05);三酰甘油与空腹血糖独立正相关(P<0.05),腰围与1/2 h血糖独立正相关(P<0.01).OGTT试验血糖水平变化的独立相关因素依次为△I30/△G330、AUCINS、HOMA-β、HOMA-IR和腰围.HbAlc水平的独立相关因素是OGTT 3 h血糖变化. 结论 在2型糖尿病、糖耐量低减及正常等不同糖代谢状态人群中,HbAlc水平存在差异,当HbAlc>8.0%时,OGTT试验、血糖、胰岛素水平或曲线下面积均不能反映出病情差别和变化的显著性.     

Sleep-disordered breathing in deep vein thrombosis and acute pulmonary embolism

Sleep-disordered breathing (SDB) may trigger thromboembolic events by enhancing intravascular clot formation. The primary objective of the present nested case-control study was to investigate whether the prevalence of SDB is increased in patients with deep vein thrombosis (DVT) and/or acute pulmonary embolism (PE). 82 consecutive patients with DVT and/or PE (cases) were prospectively enrolled irrespective of SDB-related symptoms and formed matched pairs with patients without DVT and/or PE (controls) according to sex and pre-defined categories of age and body mass index. The prevalence of SDB (respiratory disturbance index assessed by polygraphy ≥15 events·h(-1)) was significantly greater in the cases with DVT and/or PE than in controls (40 versus 26%, p=0.046) and was predominantly obstructive in nature. Multiple regression analysis revealed that SDB was significantly associated with DVT and/or PE (OR 2.28, 95% CI 1.08-4.85; p=0.032) independent of established risk factors for thrombosis. In the sex-specific analyses this association was significant in females (OR 4.14, 95% CI 1.05-16.36; p=0.042), but not in males (OR 1.55, 95% CI 0.57-4.21; p=0.391). SDB occurs more frequently in females with DVT and/or PE than in controls matched for anthropometric variables, and is independently associated with the occurrence of these thromboembolic events.