Carin Sahlin

Obstructive Sleep Apnea Is a Risk Factor for Death in Patients With Stroke: A 10-Year Follow-up

BACKGROUND Sleep apnea occurs frequently among patients with stroke, but it is still unknown whether a diagnosis of sleep apnea is an independent risk factor for mortality. We aimed to investigate whether obstructive or central sleep apnea was related to reduced long-term survival among patients with stroke. METHODS Of 151 patients admitted for in-hospital stroke rehabilitation in the catchment area of Umeå from April 1, 1995, to May 1, 1997, 132 underwent overnight sleep apnea recordings at a mean (SD) of 23 (8) days after the onset of stroke. All patients were followed up prospectively for a mean (SD) of 10.0 (0.6) years, with death as the primary outcome; no one was lost to follow-up. Obstructive sleep apnea was defined when the obstructive apnea-hypopnea index was 15 or greater, and central sleep apnea was defined when the central apnea-hypopnea index was 15 or greater. Patients with obstructive and central apnea-hypopnea indexes of less than 15 served as control subjects. RESULTS Of 132 enrolled patients, 116 had died at follow-up. The risk of death was higher among the 23 patients with obstructive sleep apnea than controls (adjusted hazard ratio, 1.76; 95% confidence interval, 1.05-2.95; P = .03), independent of age, sex, body mass index, smoking, hypertension, diabetes mellitus, atrial fibrillation, Mini-Mental State Examination score, and Barthel index of activities of daily living. There was no difference in mortality between the 28 patients with central sleep apnea and controls (adjusted hazard ratio, 1.07; 95% confidence interval, 0.65-1.76; P = .80). CONCLUSIONS Patients with stroke and obstructive sleep apnea have an increased risk of early death. Central sleep apnea was not related to early death among the present patients.

Sleep apnoea is a common occurrence in females

Obstructive sleep apnoea (OSA) is primarily regarded as a male disorder, presenting with snoring, daytime sleepiness and cardiovascular disease. We aimed to determine the frequency of sleep apnoea among females in the general population. We investigated 400 females from a population-based random sample of 10,000 females aged 20–70 yrs. They answered a questionnaire and performed overnight polysomnography. OSA (apnoea/hypopnoea index (AHI) ≥5) was found in 50% (95% CI 45–55%) of females aged 20–70 yrs. Sleep apnoea was related to age, obesity and hypertension, but not to daytime sleepiness. Severe sleep apnoea (AHI ≥30) was present in 14% (95% CI 8.1–21%) of females aged 55–70 yrs and in 31% (95% CI 12–50%) of obese females with a body mass index of ≥30 kg·m−2 aged 55–70 yrs. Sleep apnoea with daytime sleepiness and sleep apnoea with hypertension were observed as two different phenotypes of OSA. OSA occurs in 50% of females aged 20–70 yrs. 20% of females have moderate and 6% severe sleep apnoea. Sleep apnoea in females is related to age, obesity and hypertension, but not to daytime sleepiness. When searching for sleep apnoea in females, females with hypertension or obesity should be investigated.

Sleep in women: Normal values for sleep stages and position and the effect of age, obesity, sleep apnea, smoking, alcohol and hypertension

OBJECTIVES To define normal values for total sleep time, sleep latency, sleep efficiency, sleep stages and sleeping positions in women and to investigate how sleep is affected by age, obesity, sleep apnea, smoking, alcohol dependency and hypertension. METHODS In a population-based study, 400 Swedish women aged 20-70 years with over-sampling of snorers were investigated using overnight in-home polysomnography. All results are weighted. RESULTS The mean normal total sleep time was 392 min, sleep latency 22 min and sleep efficiency 82%. Women spent 31 min in sleep stage 1, 244 min in stage 2, 41 min in stage 3/4 and 76 min in rapid eye movement (REM) sleep. They spent 41% of their sleep time in the supine position, 50% in the lateral position and 9% in the prone position. Multivariate analyses revealed that sleep efficiency was lower in older women and in women with hypertension. Sleep latency was short in women with severe sleep apnea and long in smokers, alcohol-dependent and hypertensive women. Sleep stage 3/4 was inversely related to age and body mass index. Less REM sleep occurred in alcohol-dependent women. Women younger than 45 years old slept a mean of 42% in the lateral position while women of 45 years and older slept 57% in the lateral position (p<0.001). CONCLUSIONS In this population-based study of women, we present normal values for sleep stages and sleeping position. We conclude that age, body mass index, obstructive sleep apnea, smoking, alcohol and hypertension reduce sleep quality. With age, women spend more time sleeping in the lateral position.

Cheyne-Stokes respiration and supine dependency

The influence of position during sleep on central apnoeas during Cheyne-Stokes respiration has not previously been studied systematically. The current authors aimed to study the effect of body position and sleep stages on central sleep apnoeas during Cheyne-Stokes respiration. A total of 20 consecutive patients with cardiovascular diseases and central sleep apnoea during Cheyne-Stokes respiration were investigated using nocturnal polysomnography, including a body position sensor mounted on the patients sternum. The mean central apnoea–hypopnoea index was significantly higher in the supine position than in nonsupine positions (41±13 versus 26±12). The central apnoea–hypopnoea index was highest in sleep stages 1 and 2, and lowest in slow-wave sleep and rapid eye movement sleep. In every sleep stage, central apnoeas and hypopnoeas were more prevalent in the supine position compared with nonsupine positions. In conclusion, sleep in the supine body position increases the frequency of apnoeas and hypopnoeas in patients with Cheyne-Stokes respiration.

Heart rate variability during sleep and sleep apnoea in a population based study of 387 women

Increased sympathetic activity during sleep has been suggested as a link between obstructive sleep apnoea syndrome and cardiovascular disease. Heart rate variability (HRV) is a measure of autonomic effect on the heart. Different parameters have been associated with sympathetic and parasympathetic activity. We have studied HRV in different sleep stages and related the HRV‐pattern to sleep apnoea in a population‐based sample of 387 women. We investigated the HRV‐parameters standard deviation of all R‐R intervals (SDNN), root of the averaged square of successive differences (RMSSD), low frequency component (LF), high frequency component (HF), ratio of low frequency component to high frequency component LF/HF and VSAI [variation in sympathetic activity between rapid eye movement (REM) and slow wave sleep, defined as LFREM−LFSWS]. The HRV‐parameters were compared with the results of a full‐night polysomnography. Hourly incidence of obstructive episodes was used for classifying the subjects into four apnoea‐hypopnoea index (AHI)‐groups (<5, ≥5 and <15, 15–30 and >30 events). Individual sleep stages were analysed by pooling all recordings. Women with high AHI had higher heart rate and LF/HF ratio. In subjects with AHI >30, LF/HF ratio however dropped to same level as with AHI <5. Subjects with high AHI had low VSAI. Levels of SDNN, LF and LF/HF ratio during REM and light sleep were similar to wakefulness. In slow wave sleep the parameters decreased. In conclusion, moderately increased prevalence of obstructive apnoeas was associated with signs of higher sympathetic activity. High AHI was however associated with a HRV‐pattern suggestive of depressed sympathetic drive and lowered ability to increase it during REM.

Sleep Apnea and Down's Syndrome

Objective—Obstructive sleep apnea has been reported to occur in 20–50% of children with Downs syndrome in case series of patients referred for evaluation of suspected sleep apnea. In this population-based controlled study, we aimed to investigate whether sleep apnea is related to Downs syndrome. Material and Methods—Every child aged 2–10 years with Downs syndrome residing in the Umeå healthcare district (n = 28) was invited to participate in the study, with their siblings acting as controls. Successful overnight sleep apnea recordings and echocardiography were performed in 17/21 children with Downs syndrome and in 21 controls. Results—Obstructive sleep apnea could not be diagnosed, either in children with Downs syndrome or in the control children. The apnea-hypopnea index in the children with Downs syndrome was 1.2 ± 1.5 and did not differ from that in controls. Snoring and hypertrophy of the tonsils were more common in children with Downs syndrome than in controls. Children with Downs syndrome slept for a shorter time (p < 0.001) and changed body position more often (p < 0.05) than the control children. Conclusions—Snoring, restless sleep and hypertrophy of the tonsils were common among children with Downs syndrome. Obstructive sleep apnea was, however, not related to Downs syndrome in the present population-based controlled study.

Ambient temperature and obstructive sleep apnea : effects on sleep, sleep apnea and morning alertness

STUDY OBJECTIVES The aim of the study was to investigate the effect of ambient temperature on sleep, sleep apnea, and morning alertness in patients with obstructive sleep apnea. DESIGN Randomized controlled trial. SETTING In-hospital investigations. PARTICIPANTS Forty patients with obstructive sleep apnea naïve to treatment, with an apnea-hypopnea index of 10-30. INTERVENTIONS Three different nights in room temperatures of 16°C, 20°C, and 24°C. MEASUREMENTS Overnight polysomnography and Karolinska Sleepiness Scale. RESULTS The obstructive apnea-hypopnea index was 30 ± 17 at 16°C room temperature, 28 ± 17 at 20°C, and 24 ± 18 at 24°C. The obstructive apnea-hypopnea index was higher at 16°C room temperature versus 24°C (P = 0.001) and at 20°C room temperature versus 24°C (P = 0.033). Total sleep time was a mean of 30 min longer (P = 0.009), mean sleep efficiency was higher (77 ± 11% versus 71 ± 13% respectively, P = 0.012), and the patients were significantly more alert according to the Karolinska Sleepiness Scale (P < 0.028) in the morning at 16°C room temperature versus 24°C. The amount of sleep in different sleep stages was not affected by room temperature. CONCLUSIONS Untreated patients with obstructive sleep apnea sleep longer, have better sleep efficiency, and are more alert in the morning after a nights sleep at 16°C room temperature compared with 24°C, but obstructive sleep apnea is more severe at 16°C and 20°C compared with 24°C. CLINICAL TRIAL INFORMATION This study is registered in ClinicalTrials.gov number NCT00544752.

Atrial fibrillation among patients under investigation for suspected obstructive sleep apnea

Study objectives Obstructive sleep apnea is common among patients with atrial fibrillation, but the prevalence and risk factors for atrial fibrillation among patients who are being investigated on suspicion of sleep apnea are not well known. The aim of the study was to estimate the prevalence of atrial fibrillation among patients investigated for suspected obstructive sleep apnea and to identify risk factors for atrial fibrillation among them. Methods The prevalence of atrial fibrillation was investigated among 201 patients referred for suspected obstructive sleep apnea. Patients without known atrial fibrillation were investigated with a standard 12-lead ECG at hospital and short intermittent handheld ECG recordings at home, during 14 days. Results Atrial fibrillation occurred in 13 of 201 subjects (6.5%), and in 12 of 61 men aged 60 years and older (20%). The prevalence of atrial fibrillation increased with sleep apnea severity (p = 0.038). All patients with atrial fibrillation were men and all had sleep apnea. Age 60 or older, the occurrence of central sleep apnea and diabetes mellitus were independent risk factors for atrial fibrillation after adjustments for body mass index, gender, sleep apnea and cardiovascular disease. Conclusions Atrial fibrillation is common among subjects referred for sleep apnea investigation and the prevalence of atrial fibrillation increases with sleep apnea severity. Independent risk factors for atrial fibrillation among patients investigated for suspected obstructive sleep apnea include the occurrence of coexisting central sleep apnea, age 60 years or older and diabetes mellitus.

Cardioversion of atrial fibrillation does not affect obstructive sleep apnea

Abstract Background: Sleep apnea is common in patients with atrial fibrillation, but the effect of the cardioversion of atrial fibrillation to sinus rhythm on central and obstructive apneas is mainly unknown. The primary aim of the study was to analyze the association between cardioversion of atrial fibrillation and sleep apneas, to investigate whether obstructive or central sleep apneas are reduced following cardioversion. A secondary objective was to study the effect on sleep quality. Methods: Twenty-three patients with atrial fibrillation were investigated using overnight polysomnography, including esophagus pressure monitoring and ECG, before and after the cardioversion of persistent atrial fibrillation. Results: Obstructive sleep apnea occurred in 17/23 patients (74%), and central sleep apnea in 6/23 patients (26%). Five patients had both obstructive and central sleep apnea. Sinus rhythm at follow-up was achieved in 16 patients. The obstructive apnea-hypopnea index, central apnea-hypopnea index, and the number of patients with obstructive or central sleep apnea did not differ before and after restoration of sinus rhythm. Sleep time, sleep efficiency, time in different sleep stages, and subjective daytime sleepiness were normal and unaffected by cardioversion. Conclusions: Both obstructive and central sleep apneas are highly prevalent in patients with persistent atrial fibrillation. Obstructive sleep apneas are unaffected by the cardioversion of atrial fibrillation to sinus rhythm. The sleep pattern is normal and unaffected by cardioversion in patients with atrial fibrillation. Clinical Trial Registration: Trial number NCT00429884.

Nocturnal Blood Pressure Is Reduced by a Mandibular Advancement Device for Sleep Apnea in Women: Findings From Secondary Analyses of a Randomized Trial

Background Obstructive sleep apnea is associated with high blood pressure. The magnitude of blood pressure effects from sleep apnea treatment is unclear. We aimed to determine the effect of mandibular advancement device therapy on ambulatory nighttime and daytime blood pressure in women and men with daytime sleepiness and snoring or mild to moderate sleep apnea (apnea‐hypopnea index, <30). Methods and Results In this 4‐month, double‐blind, randomized controlled trial comprising 96 untreated patients, 27 women and 58 men, aged 31 to 70 years, completed the study. The active group received individually made adjustable mandibular advancement devices, and the control group was given individually made sham devices, to be used during sleep. Polysomnographic sleep recordings and ambulatory 24‐hour blood pressure measurements were performed at baseline and at follow‐up. In women with mandibular advancement devices, the mean nighttime systolic blood pressure was 10.8 mm Hg (95% confidence interval, 4.0–17.7 mm Hg; P=0.004) lower than in the women in the sham group, adjusted for baseline blood pressure, age, body mass index, and the apnea‐hypopnea index. The mean nighttime adjusted diastolic blood pressure was 6.6 mm Hg (95% confidence interval, 2.7–10.4 mm Hg; P=0.002) lower in the mandibular advancement device group. In men, there were no significant differences in blood pressure at night or during the daytime between the intervention groups. Conclusions A mandibular advancement device for obstructive sleep apnea reduces nocturnal blood pressure in women. Clinical Trial Registration URL: https://www.clinicaltrials.gov. Unique identifier: NCT00477009.