Evolution of mild obstructive sleep apnea after different treatments

Clinical phenotype of obstructive sleep apnea in older adults: a hospital-based retrospective study in China

BACKGROUND

The prevalence of obstructive sleep apnea (OSA) in older people (aged over 65 years) is high. However, OSA in older populations has not received sufficient attention. This study examined the clinical phenotypic characteristics of older patients with newly diagnosed OSA.

METHODS

A total of 110 older patients (≥ 65 years) and 220 younger patients (< 65 years), matched by gender, body mass index (BMI), and apnea-hypopnea index (AHI), were enrolled in this retrospective study. Clinical manifestations, comorbidities, and polysomnographic results were compared between the two groups, and correlations between age ≥ 65 years and OSA comorbidities were explored.

RESULTS

Nocturia was more common in older patients with OSA, as with lower sleep efficiency, longer wake after sleep onset, increased stage N1 sleep, and decreased stage N3 sleep and average SpO2. The proportions of older OSA patients who had comorbid hypertension, coronary artery disease (CAD), chronic obstructive pulmonary disease, and ischemic stroke were significantly higher than those of younger patients. The incidence of tonsillar enlargement and pharyngeal narrowing was lower in older patients. Age ≥ 65 years was an independent risk factor for patients with OSA to have hypertension (OR: 1.89, 95% CI: 1.11-3.21), CAD (OR: 4.83, 95% CI: 2.29-10.21), and ischemic stroke (OR: 2.92, 95% CI: 1.02 to 8.38).

CONCLUSIONS

The presence of OSA in older adults was associated with significant abnormalities of sleep architecture, aggravated nocturnal hypoxia and increased risks of hypertension, CAD, and stroke, which can be distinguished as a unique clinical phenotype.

Should mild obstructive sleep apnoea be treated? A systematic review from the standpoint of disease progression

OBJECTIVE

This study was a systematic review to investigate the progression of untreated obstructive sleep apnoea in order to evaluate whether mild obstructive sleep apnoea should be treated from the standpoint of disease progression.

METHOD

The database search study outcomes that were collected included Apnea Hypopnea Index and Respiratory Disturbance Index. A meta-analysis of obstructive sleep apnoea severity over time intervals was performed.

RESULTS

A total of 17 longitudinal studies and 1 randomised, controlled trial were included for review. For patients with mild obstructive sleep apnoea, mean pre-study and post-study Apnea Hypopnea Index was 5.21 and 8.03, respectively, over a median interval of 53.1 months. In patients with moderate to severe obstructive sleep apnoea, mean pre-study and post-study Apnea Hypopnea Index was 28.9 and 30.3, respectively, over a median interval of 57.8 months. Predictors for disease progression in mild obstructive sleep apnoea are patients aged less than 60 years and those with a baseline body mass index less than 25.

CONCLUSION

Mild obstructive sleep apnoea progression is observed, but it does not appear to reach any clinically significant progression to moderate or severe obstructive sleep apnoea.

Treatment of sleep disordered breathing relapse after surgery

This narrative review provides a general overview of the management of relapses after surgery for the treatment of sleep disordered breathing. This clinical scenario represents a challenging field, but fortunately several therapeutic options are included in sleep surgeons’ armamentarium. Each therapeutic modality is described in detail in a dedicated section.

Association of Obstructive Sleep Apnea With White Matter Integrity and Cognitive Performance Over a 4-Year Period in Middle to Late Adulthood

IMPORTANCE

Obstructive sleep apnea (OSA) is associated with cognitive impairment and brain structural alterations, but longitudinal outcomes are understudied.

OBJECTIVE

To examine the associations of OSA with cognition and white matter (WM) integrity over a 4-year period.

DESIGN, SETTING, AND PARTICIPANTS

This prospective cohort study was conducted in a community-based adult population among participants who had both baseline (2011-2014) and 4-year follow-up (2015-2018) polysomnography, diffusion tensor imaging, and cognitive assessment data. Participants with neurological disorders, anomalous findings on brain magnetic resonance imaging, or inadequate quality of the evaluations were excluded. Data were analyzed from March to November 2021.

EXPOSURES

Participants were categorized depending on the presence vs absence of OSA at baseline and follow-up polysomnographic analysis.

MAIN OUTCOMES AND MEASURES

The main outcomes were proportional changes over a 4-year period in neuropsychological performance and WM integrity. The neuropsychological assessment battery included verbal and visual memory, verbal fluency, Digit Symbol-coding, Trail Making Test-A, and Stroop Test. WM integrity was assessed by fractional anisotropy, axial, and radial diffusivity. To examine interactions with age and sex, participants were subgrouped by age older than 60 years vs 60 years or younger and men vs women.

RESULTS

A total of 1998 individuals were assessed for eligibility, and 888 were excluded based on exclusion criteria, leaving 1110 participants (mean [SD] age, 58.0 [6.0] years; 517 [46.6%] men) for analysis, including 458 participants grouped as OSA-free, 72 participants with resolved OSA, 163 participants with incident OSA, and 417 participants with persistent OSA. Incident OSA was associated with altered WM integrity and with concomitant changes in sustained attention compared with participants without OSA (eg, change in Digit Symbol-coding test score, -3.2% [95% CI, -5.2% to -1.2%]). Participants with resolved OSA showed better visual recall at the follow-up (change in Visual Reproduction-immediate recall test, 17.5% [95% CI, 8.9% to 26.1%]; change in Visual Reproduction-delayed recall test, 33.1% [95% CI, 11.3% to 54.9%]), with concordant changes in diffusion parameters at the relevant anatomic areas. In the older group only (age >60 years), persistent OSA was associated with altered WM integrity and cognition (eg, Visual Reproduction-recognition test: β = -24.2 [95% CI, -40.7 to -7.7]). Sex also was associated with modifying the association of OSA with WM integrity of the left posterior internal capsule, the left genu of corpus callosum, and the right middle cerebellar peduncle only in men and with cognition only in women (eg, Visual Reproduction-immediate recall test: β = 33.4 [95% CI, 19.1 to 47.7]).

CONCLUSIONS AND RELEVANCE

These findings suggest that dynamic changes in OSA status were significantly associated with WM integrity and cognition, which varied by age and sex. It is possible that adequate interventions for OSA could better preserve brain health in middle to late adulthood.

The Worsening of Positional Mild Obstructive Sleep Apnea over Time Is Associated with an Increase in Body Weight: Impact on Blood Pressure and Autonomic Nervous System

BACKGROUND

Most patients with mild obstructive sleep apnea (OSA) are positional dependent. Although mild OSA worsens over time, no study has assessed the natural course of positional mild OSA.

OBJECTIVES

The aim of this study was to evaluate the natural course of positional mild OSA, its most valuable progression predictor, and its impact on blood pressure (BP) and the autonomic nervous system (ANS).

METHODS

This retrospective observational cohort study enrolled 86 patients with positional mild OSA and 26 patients with nonpositional mild OSA, with a follow-up duration of 32.0 ± 27.6 months and 37.6 ± 27.8 months, respectively. Polysomnographic variables, BP, and ANS functions were compared between groups at baseline and after follow-up.

RESULTS

In patients with positional mild OSA after follow-up, the apnea/hypopnea index (AHI) increased (9.1 ± 3.3/h vs. 22.0 ± 13.2/h, p = 0.000), as did the morning systolic BP (126.4 ± 13.3 mm Hg vs. 130.4 ± 15.9 mm Hg, p = 0.011), and the sympathetic activity (49.4 ± 12.3% vs. 55.3 ± 13.1%, p = 0.000), while the parasympathetic activity decreased (50.6 ± 12.3% vs. 44.7 ± 13.1%, p = 0.000). The body mass index changes were the most important factor associated with AHI changes among patients with positional mild OSA (Beta = 0.259, adjust R2 = 0.056, p = 0.016, 95% confidence interval 0.425 and 3.990). The positional dependency disappeared over time in 66.3% of patients with positional mild OSA while 69.2% of patients with nonpositional mild OSA retained nonpositional.

CONCLUSIONS

In patients with positional mild OSA, disease severity, BP, and ANS regulation worse over time. Increased weight was the best predictor for its progression and the loss of positional dependency. Better treatments addressing weight control and consistent follow-up are needed for positional mild OSA.

Cardiac imageology changes in patients with mild obstructive sleep apnea without cardiovascular disease

PURPOSE

This study aims to assess changes in cardiac imageology of patients with mild obstructive sleep apnea (OSA) without cardiovascular disease.

METHODS

All enrolled participants underwent polysomnography (PSG). Some participants underwent transthoracic echocardiography, speckle tracking echocardiography, and cardiac-enhanced magnetic resonance imaging (MRI) if they were willing. They were divided into three groups according to PSG results: non-OSA, mild OSA, and moderate-to-severe OSA. Imageology parameters were compared, and the relationship between OSA severity and imageology indices was analyzed by correlation analysis and multiple linear regression.

RESULTS

Of the 352 enrolled participants, 274 participants with OSA had an apnea-hypopnea index (AHI) of ≥ 5 (86 mild OSA and 188 moderate-to-severe OSA cases), and 78 participants with non-OSA had an AHI of < 5. Transthoracic echocardiography showed that E/A and E'/A' values were lower in the mild OSA group than in the non-OSA group (1.12 ± 0.37 vs 1.27 ± 0.45 and 0.83 ± 0.33 vs 0.99 ± 0.42, respectively, p < 0.05). The aorta and ascending aorta widths were smaller in the mild OSA group than in the moderate-and-severe OSA groups (27.36 ± 2.87 mm vs 28.87 ± 2.95 mm and 30.27 ± 3.79 mm vs 31.63 ± 3.74 mm, respectively, p < 0.05). A regression analysis showed that cardiac function changes in patients with OSA may be related to age, obesity, and OSA severity.

CONCLUSION

Patients with mild OSA without cardiovascular disease displayed changes in cardiac structure and function on transthoracic echocardiography.

Mild obstructive sleep apnea increases hypertension risk, challenging traditional severity classification

STUDY OBJECTIVES

The association of mild obstructive sleep apnea (OSA) with important clinical outcomes remains unclear. We aimed to investigate the association between mild OSA and systemic arterial hypertension (SAH) in the European Sleep Apnea Database cohort.

METHODS

In a multicenter sample of 4,732 participants, we analyzed the risk of mild OSA (subclassified into 2 groups: mild_{AHI 5-<11/h} (apnea-hypopnea index [AHI], 5 to <11 events/h) and mild_{AHI 11-<15/h} (AHI, ≥11 to <15 events/h) compared with nonapneic snorers for prevalent SAH after adjustment for relevant confounding factors including sex, age, smoking, obesity, daytime sleepiness, dyslipidemia, chronic obstructive pulmonary disease, type 2 diabetes, and sleep test methodology (polygraphy or polysomnography).

RESULTS

SAH prevalence was higher in the mild_{AHI 11-<15/h} OSA group compared with the mild_{AHI 5-<11/h} group and nonapneic snorers (52% vs 45% vs 30%; P < .001). Corresponding adjusted odds ratios for SAH were 1.789 (mild_{AHI 11-<15/h}; 95% confidence interval [CI], 1.49-2.15) and 1.558 (mild_{AHI 5-<11/h}; 95%, CI, 1.34-1.82), respectively (P < .001). In sensitivity analysis, mild_{AHI 11-<15/h} OSA remained a significant predictor for SAH both in the polygraphy (odds ratio, 1.779; 95% CI, 1.403-2.256; P < .001) and polysomnography groups (odds ratio, 1.424; 95% CI, 1.047-1.939; P = .025).

CONCLUSIONS

Our data suggest a dose-response relationship between mild OSA and SAH risk, starting from 5 events/h in polygraphy recordings and continuing with a further risk increase in the 11- to <150-events/h range. These findings potentially introduce a challenge to traditional thresholds of OSA severity and may help to stratify participants with OSA according to cardiovascular risk.

The role of long-term continuous positive airway pressure in the progression of obstructive sleep apnoea: A longitudinal cohort study

Recent evidence suggests that short-term obstructive sleep apnea (OSA) treatment could affect OSA pathogenesis such as ventilatory control. The aim of our present study was to identify the impact of long-term treatment on the change in pathogenesis and natural progression of OSA. In a longitudinal analysis of a non-obese cohort study, patients with OSA treated with either continuous positive airway pressure (CPAP) or an oral appliance (OA), interrupted their treatment for 1 week and underwent a polysomnography (PSG) off treatment that was compared with their initial PSG taken 5 years before treatment initiation. In all, 154 consecutive patients with OSA who were treated by CPAP using an auto-titrating continuous positive airway pressure device (CPAP-APAP) (n = 112), or by OA (n = 27) or were untreated (n = 15), PSG was performed twice with a median (range) follow-up of 93 (60-176) months. Multivariate logistic regression showed that reduction of body mass index (BMI) and good treatment adherence to be significant predictors of favourable OSA progression, as represented by an improved or unchanged apnea-hypopnea index (AHI) (odds ratios were 5.14 and 2.89, respectively). Amongst the patients with an unchanged BMI and good CPAP-APAP adherence (n = 55), the improvement in AHI was significantly associated with the decrease in supine non-rapid eye movement-AHI and mixed apnoea index/apnoea index, which are generally recognised to be determinants of ventilator instability. These findings suggest that not only weight but also treatment adherence are determinants in the natural progression of OSA severity.

Natural History of Sleep-disordered Breathing during Rapid Eye Movement Sleep. Relevance for Incident Cardiovascular Disease

Rationale: Sleep-disordered breathing (SDB) occurring primarily during rapid eye movement (REM) sleep is a common clinical problem. The natural history of REM-related SDB and the associated cardiovascular sequelae of disease progression remain to be determined.Objectives: The objective of the current study was to describe the natural history of REM-related SDB, ascertain predictors of progression, and determine whether the evolution of REM-related SDB into non-REM (NREM) sleep is associated with incident cardiovascular events.Methods: Participants from the Sleep Heart Health Study with a baseline NREM apnea-hypopnea index (NREM-AHI) of <5 events/h and data from a follow-up sleep study along with information on incident cardiovascular disease were included in the study. Bivariate logistic regression was used to jointly model the predictors of disease progression based on the presence or absence of SDB during NREM and REM sleep using a cut-point of 5 events/h. Explanatory variables such as age, race, body mass index (BMI), change in BMI, and baseline REM-AHI were considered. Proportional hazards regression was then used to establish whether the development of SDB during NREM sleep was associated with incident cardiovascular disease.Results: The majority of the 1,908 participants included in the study did not develop SDB during NREM sleep. The likelihood of progression of SDB into NREM sleep did increase with higher baseline REM-AHI. BMI and an increase in BMI predicted progression of SDB in both NREM and REM sleep in men but not in women. There was a strong interdependence between developing a NREM-AHI of ≥5 events/h and worsening REM-AHI at follow-up with odds ratios of 6.01 and 4.47, in women and men, respectively. Moreover, the relative risk for incident cardiovascular events among those who developed a NREM-AHI of ≥5 events/h at the follow-up visit was elevated only in women with REM-related SDB at baseline.Conclusions: SDB during REM sleep is a relatively stable condition and does not progress in the majority of individuals. Progression of SDB into NREM sleep is associated with sex, weight, and age. SDB during REM and NREM sleep tends to develop concurrently. Finally, the development of SDB during NREM sleep is associated with incident cardiovascular events, but only in women with REM-related SDB at baseline.

Obstructive Sleep Apnea and the Brain: a Focus on Gray and White Matter Structure

PURPOSE OF REVIEW

Obstructive sleep apnea is extremely prevalent in the elderly and may precipitate dementia. We review recent advances on gray and white matter structure in obstructive sleep apnea, the impact of treatment, and potential pathological and neurodegenerative processes underlying brain structural changes.

RECENT FINDINGS

Two opposite patterns are observed in neuroimaging studies of obstructive sleep apnea. One may indicate cellular damage (gray matter atrophy, higher white matter hyperintensity burden, lower white matter fractional anisotropy, higher water diffusivities), while the other (gray matter hypertrophy, restricted white matter diffusivities) may reflect transitory responses, such as intracellular edema, reactive gliosis or compensatory structural changes. Treating obstructive sleep apnea could partly reverse these structural changes. Structural alterations related to obstructive sleep apnea may follow a multi-determined biphasic pattern depending on numerous factors (e.g. severity, symptomatology, age) that could tip the scale toward neurodegeneration and need to be investigated by longitudinal studies.

Cerebral white matter diffusion properties and free-water with obstructive sleep apnea severity in older adults

Characterizing the effects of obstructive sleep apnea (OSA) on the aging brain could be key in our understanding of neurodegeneration in this population. Our objective was to assess white matter properties in newly diagnosed and untreated adults with mild to severe OSA. Sixty‐five adults aged 55 to 85 were recruited and divided into three groups: control (apnea‐hypopnea index ≤5/hr; n = 18; 65.2 ± 7.2 years old), mild (>5 to ≤15 hr; n = 27; 64.2 ± 5.3 years old) and moderate to severe OSA (>15/hr; n = 20; 65.2 ± 5.5 years old). Diffusion tensor imaging metrics (fractional anisotropy (FA), axial diffusivity (AD), radial diffusivity, and mean diffusivity) were compared between groups with Tract‐Based Spatial Statistics within the white matter skeleton created by the technique. Groups were also compared for white matter hyperintensities volume and the free‐water (FW) fraction. Compared with controls, mild OSA participants showed widespread areas of lower diffusivity (p < .05 corrected) and lower FW fraction (p < .05). Participants with moderate to severe OSA showed lower AD in the corpus callosum compared with controls (p < .05 corrected). No between‐group differences were observed for FA or white matter hyperintensities. Lower white matter diffusivity metrics is especially marked in mild OSA, suggesting that even the milder form may lead to detrimental outcomes. In moderate to severe OSA, competing pathological responses might have led to partial normalization of diffusion metrics.

Modest Improvement of Untreated Severe Sleep-Disordered Breathing in the Middle-Aged and Elderly

OBJECTIVE

It has been reported that untreated sleep-disordered breathing (SDB) deteriorates over time, however this remains contentious. The aim of the present study is to evaluate the clinical course of SDB in middle-aged and older SDB patients, and to identify how relevant factors contribute to the change in SDB severity.

METHODS

Baseline and follow-up polysomnographic data of 56 untreated SDB patients (mean age, 61.2±5.71) were obtained retrospectively and the mean interval was 62.4±22.0 months. Subgroup analysis was performed based on the baseline severity, and the factors associated with the course of SDB were analyzed.

RESULTS

At the baseline, 13 subjects were simple snorers, 15 had mild to moderate SDB, and 28 were severe SDB patients. While there was no significant change in apnea-hypopnea index (AHI) as a whole, subgroup analysis showed decrease of AHI in severe SDB patients (43.9±10.6 to 35.6±20.0, p=0.009). The change in supine time percent and baseline AHI were associated with the change in AHI (β=0.387, p=0.003; β=-0.272, p=0.037).

CONCLUSION

Untreated SDB did not deteriorate over time with modest improvement in severe SDB. A proportion of severe SDB patients might expect decrease in SDB severity irrespective of changes in sleep position or body weight.

Comparison of cardiovascular co-morbidities and CPAP use in patients with positional and non-positional mild obstructive sleep apnea

BACKGROUND

This retrospective cohort study aimed to determine if there are differences in cardiovascular co-morbidities, blood pressure (BP) and continuous positive airway pressure (CPAP) use between patients with positional-dependent and nonpositional-dependent obstructive sleep apnea (OSA).

METHODS

Patients who were referred for overnight polysomnography for suspected OSA between 2007 and 2011 were screened. A total of 371 patients with OSA were included for analysis and divided into six groups according to positional-dependency and severity of OSA: positional mild (n = 52), positional moderate (n = 29), positional severe (n = 24), non-positional mild (n = 18), non-positional moderate (n = 70) and non-positional severe group (n = 178). The six groups were compared for anthropometric and polysomnographic variables, presence of cardiovascular co-morbidities, morning and evening BP and the changes between evening and morning BP, and CPAP device usage patterns.

RESULTS

Demographic and anthropometric variables showed non-positional severe OSA had poor sleep quality and higher morning blood pressures. Positional mild OSA had the lowest cardiovascular co-morbidities. Overall CPAP acceptance was 45.6%. Mild OSA patients had the lowest CPAP acceptance rate (10%), followed by moderate group (37.37%) and severe group (61.88%, P < 0.001). However, the significant difference in CPAP acceptance across OSA severity disappeared when the data was stratified by positional dependency.

CONCLUSIONS

This study found that positional mild OSA had less cardiovascular co-morbidities compared with subjects with positional severe OSA. Independent of posture, CPAP acceptance in patients with mild OSA was low, but CPAP compliance was similar in CPAP acceptors regardless of posture dependency of OSA. Since there are increasing evidences of greater cardiovascular risk for untreated mild OSA, improving CPAP acceptance among mild OSA patients may be clinically important regardless of posture dependency.

Endothelial function is well preserved in obese patients with mild obstructive sleep apnea

PURPOSE

Endothelial dysfunction is one of the early markers of cardiovascular complications in obstructive sleep apnea (OSA). The aim of our study was to evaluate whether overweight patients with mild OSA displayed endothelial dysfunction, and to assess the effect of 1-year lifestyle intervention with an early very low calorie diet in endothelial function.

METHODS

At baseline, the study population consisted of 83 overweight patients with mild OSA and 46 weight-matched non-OSA subjects. OSA patients were further randomized into a 1-year supervised lifestyle intervention group or control group which received routine lifestyle counselling. Endothelial function measured by brachial artery flow-mediated dilatation (FMD), apnea-hypopnea index (AHI), body mass index (BMI), and metabolic parameters were assessed at baseline and 12 months.

RESULTS

No correlations between endothelial function and mild OSA were detected. However, patients with impaired endothelial function had lower mean saturation and impaired endothelial function correlated significantly with glucose intolerance and dyslipidemia. After the lifestyle intervention and successful weight reduction, AHI, BMI, serum triglycerides and insulin improved significantly; however, no improvement in FMD was detected.

CONCLUSIONS

Mild OSA was not observed to be associated with endothelial dysfunction. Although in mild OSA endothelial function is still preserved, lifestyle intervention with weight reduction did achieve an improvement in other obesity-related risk factors for cardiovascular diseases, thus highlighting the importance of early intervention.

Craniofacial morphology but not excess body fat is associated with risk of having sleep-disordered breathing--the PANIC Study (a questionnaire-based inquiry in 6-8-year-olds)

We investigated the associations of dental occlusion, other craniofacial features and body fat with paediatric sleep-disordered breathing (SDB) in a representative population sample of 491 Finnish children 6-8 years of age. Overweight and obesity were defined using age- and sex-specific body mass index cutoffs by International Obesity Task Force (IOTF) criteria. Body fat percentage was assessed by dual-energy X-ray absorptiometry. Facial proportions, dental occlusion and soft tissue structures were evaluated by an orthodontist. Sleep was assessed by a sleep questionnaire administered by the parents. SDB was defined as apnoeas, frequent or loud snoring or nocturnal mouth breathing observed by the parents. The prevalence of SDB was 9.9 % with no difference between boys and girls. The median (interquartile range) of body fat percentage was 20.6 (17.4-27.1) in girls and 15.0 (11.4-21.6) in boys. Altogether 11.4 % of boys and 15.6 % of girls were classified as having overweight or obesity according to the IOTF criteria. There was no difference in the prevalence of overweight, obesity or body fat percentage between children with SDB and those without it. Children with tonsillar hypertrophy had a 3.7 times higher risk of suffering SDB than those with normal size tonsils after adjustment for age, sex and body fat percentage. Furthermore, children with cross bite had a 3.3 times higher risk of having SDB than those without cross bite, and children with a convex facial profile had a 2.6 times higher risk of having SDB than those with a normal facial profile.

CONCLUSION

Abnormal craniofacial morphology, but not excess body fat, is associated with an increased risk of having SDB in 6-8-year-old children. A simple model of necessary clinical examinations (i.e. facial profile, dental occlusion and tonsils) is recommended to recognize children with an increased risk of SDB.

Obesity and obstructive sleep apnea--clinical significance of weight loss

Obesity is a major health burden that contributes to increased morbidity and mortality. Obesity is also the most important risk factor for obstructive sleep apnea (OSA); at least 70% of patients are obese. OSA as such, has been linked with increased cardiovascular morbidity and mortality, and OSA patients often display metabolic syndrome. The exact underlying mechanisms behind these associations are complex and not fully understood. In obese individuals, weight reduction and increased physical activity form cornerstones for the prevention and treatment of metabolic syndrome, and recent controlled intervention trials strongly suggest that weight reduction together with a healthy diet and increased physical activity may correct or at least improve the symptoms of OSA. However, regardless of promising results in terms of symptoms of OSA and the undoubted metabolic benefits of changing lifestyles, weight reduction as a treatment of OSA is still underrated by many clinicians. Based on the current knowledge, clinicians should revise their previous attitudes, including suspicions about weight reduction as an effective treatment for OSA patients. Nevertheless, we also need large well-controlled trials on the effects of different weight reduction programs among OSA patients to determine the overall efficacy of different treatment modalities and their long-term success.

Total duration of apnea and hypopnea events and average desaturation show significant variation in patients with a similar apnea-hypopnea index

Obstructive sleep apnea (OSA) is commonly diagnosed based on the apnea-hypopnea index (AHI). Presently, novel indices were introduced for sleep apnea severity: total duration of sleep apnea and hypopnea events (TAHD%) and a combined index including duration and severity of the events (TAHD% × average desaturation). Two hundred and sixty-seven subjects were divided based on their AHI into four categories (normal, mild, moderate, severe OSA). In the most severe cases TAHD% exceeded 70% of the recorded time. This is important as excessive TAHD% may increase mortality and cerebro-vascular complications. Moreover, simultaneous increase in duration and frequency of apnea and hypopnea events leads to a paradoxical situation where AHI cannot increase along severity of the disease. Importantly, the combined index including duration and severity of the events showed significant variation between patients with similar apnea-hypopnea indices. To conclude, the present results suggest that the novel parameters could give supplementary information to AHI when diagnosing the severity of OSA.

Risk factors for sleep-disordered breathing: the role of craniofacial structure

OBJECTIVE

To evaluate possible differences in craniofacial structure between overweight patients and normal-weight patients with mild sleep-disordered breathing (SDB).

MATERIAL AND METHODS

Subjects were recruited from patients referred to Kuopio University Hospital due to suspicion of SDB. They were divided into two groups based on their body mass index (BMI). The overweight group (BMI > 27 kg/m(2)) consisted of 58 males and 19 females and the normal weight group (BMI ≤ 27 kg/m(2)) of 33 males and 15 females. The mean age of the subjects was 51.4 years. All subjects underwent an overnight cardiorespiratory recording. The mean apnea-hypopnea index (AHI) was 9.3 events/h for the entire study population. Occlusion and craniofacial morphology were examined by an experienced orthodontist.

RESULTS

Significant differences in craniofacial morphology and occlusion were found between the groups: the craniofacial profile in normal-weight patients was more convex (P < 0.000) and the mandible more retrusive (P = 0.004) than in overweight subjects. In addition, distal molar occlusion (P = 0.005) was more prevalent in normal-weight subjects, and their overjet and overbite were increased as compared to overweight patients (P = 0.009 and 0.006, respectively). Similarly, cross bite was detected significantly more often in normal-weight subjects (P = 0.052).

CONCLUSIONS

These results reveal that deviations in craniofacial morphology and occlusion are more frequent in normal subjects than in overweight subjects with mild SDB; this may well have implications in the pathophysiology of SDB.

Sustained improvement in mild obstructive sleep apnea after a diet- and physical activity-based lifestyle intervention: postinterventional follow-up

BACKGROUND

Obesity is the most important risk factor for obstructive sleep apnea (OSA). Weight-reduction programs have been observed to represent effective treatment of overweight patients with OSA. However, it is not known whether beneficial changes remain after the end of the intervention.

OBJECTIVE

The aim of the study was to assess the long-term efficacy of a lifestyle intervention based on a healthy diet and physical activity in a randomized, controlled, 2-y postintervention follow-up in OSA patients.

DESIGN

Eighty-one consecutive overweight [body mass index (in kg/m(2)): 28-40] adult patients with mild OSA were recruited. The intervention group completed a 1-y lifestyle modification regimen that included an early 12-wk weight-reduction program with a very-low-calorie diet. The control group received routine lifestyle counseling. During the second year, no dietary counseling was offered. Change in the apnea-hypopnea index (AHI) was the main objective outcome variable, and changes in symptoms were used as a subjective measurement.

RESULTS

A total of 71 patients completed the 2-y follow-up. The mean (± SD) changes in diet and lifestyle with simultaneous weight reduction (-7.3 ± 6.5 kg) in the intervention group reflected sustained improvements in findings and symptoms of OSA. After 2 y, the reduction in the AHI was significantly greater in the intervention group (P = 0.049). The intervention lowered the risk of OSA at follow-up; the adjusted odds ratio for OSA was 0.35 (95% CI: 0.12-0.97; P = 0.045).

CONCLUSION

Favorable changes achieved by a 1-y lifestyle intervention aimed at weight reduction with a healthy diet and physical activity were sustained in overweight patients with mild OSA after the termination of supervised lifestyle counseling. This trial was registered at clinicaltrials.gov as NCT00486746.

Surgical intervention represents a feasible option for patients with mild obstructive sleep apnoea

CONCLUSIONS

Patients with mild obstructive sleep apnoea (OSA) depict the disease as being detrimental to their health, causing significant symptoms. These patients were found to achieve significant improvements in OSA-related symptoms after surgical intervention.

OBJECTIVES

Although the effects of surgical treatment on OSA have been encouraging in many previous studies, little is known about its effects in patients with mild OSA. The aim of our study was to assess the evolution of symptoms experienced by mild OSA patients after surgical intervention.

SUBJECTS AND METHODS

This was an observational follow-up study in a university hospital in Finland. The change in daytime and night-time symptoms was assessed by a standardized questionnaire before treatment and after a mean follow-up time of 3 years in both operative and control groups in 81 adult patients with mild OSA.

RESULTS

At the follow-up, the control group experienced significantly more daytime sleepiness (p<0.001) compared with the operative group. Adjusted odds ratio (OR) for daytime sleepiness was 0.05 (95% CI 0.01-0.25, p<0.001) in operatively treated patients as compared with control patients, with improvement of witnessed apnoeas (p<0.001) and sleep quality (p=0.033). The OR for intensive snoring was 0.06 (95% CI 0.02-0.22) in the operative group as compared with the control group.

Accuracy of automatic analysis of ambulatory recordings of nocturnal breathing disorders is significantly instrumentation dependent

Obstructive sleep apnoea (OSA) is generally diagnosed with ambulatory recordings. Although reliability of automated analysis has been investigated, suitability of one single analysis software for use with different devices is unclear. Here, validity of automatic analysis of recordings with two ambulatory devices and reliability of automatic analysis in detection of mixed and central apnoeas are investigated through 100 and 167 recordings with Venla and Embletta devices, respectively. Recordings were analysed automatically with Somnologica 3.2 and compared to manual analysis. Significant differences were seen between devices in classification of the severity of OSA when automatic analysis was applied. 65.4% and 11.4% of patients with mild obstructive sleep apnoea received false negative diagnosis with Venla and Embletta, respectively. Further, as automatic analysis was seen to have major difficulty in detection and classification of central and mixed apnoeas, manual analysis is suggested when these forms of disease are suspected.

Radiofrequency surgery of the soft palate in the treatment of mild obstructive sleep apnea is not effective as a single-stage procedure: A randomized single-blinded placebo-controlled trial

OBJECTIVES/HYPOTHESIS

Radiofrequency (RF) surgery of the soft palate (SP) is an established treatment option for the treatment of snoring. Due to its minimally invasive character, it has received attention in the management of mild obstructive sleep apnea syndrome (OSAS).

STUDY DESIGN

The aim of this study was to assess the efficacy and the occurrence of adverse events after single-stage SP RF surgery in patients with mild OSAS in a randomized single-blinded placebo-controlled trial in an outpatient department at a tertiary care center, academic teaching hospital.

METHODS

Thirty-two patients with mild OSAS (apnea-hypopnea index [AHI] 5-15, body mass index <35) were randomized to receive a single session of RF surgery or placebo (insertion of applicator without energy delivery) with local anesthesia. The primary outcome measures were (AHI), Epworth Sleepiness Scale, and a 36-item short-form health survey quality-of-life questionnaire. The secondary measures were the soft tissue airway parameters in cephalometric radiographs, snoring scores, and rates of adverse events.

RESULTS

Neither objectively measured significances (active AHI 11.0 [5.0-9.0] to 13.0 [2.0-26.0] and placebo AHI 12.0 [5.0-8.0] to 11.0 [1.0-29.0], P = .628), nor were trends of a diminishing effect on symptoms of mild OSAS found in the treatment arms. No significant changes in the soft tissue airway parameters occurred. One patient (5.9%) in the active treatment group was cured.

CONCLUSIONS

RF surgery of SP is not recommended as a single-stage approach in mild OSAS.

Lifestyle intervention with weight reduction: first-line treatment in mild obstructive sleep apnea

RATIONALE

Obesity is the most important risk factor for obstructive sleep apnea (OSA). However, although included in clinical guidelines, no randomized controlled studies have been performed on the effects of weight reduction on mild OSA.

OBJECTIVES

The aim of this prospective, randomized controlled parallel-group 1-year follow-up study was to determine whether a very low calorie diet (VLCD) with supervised lifestyle counseling could be an effective treatment for adults with mild OSA.

METHODS

Seventy-two consecutive overweight patients (body mass index, 28-40) with mild OSA were recruited. The intervention group (n = 35) completed the VLCD program with supervised lifestyle modification, and the control group (n = 37) received routine lifestyle counseling. The apnea-hypopnea index (AHI) was the main objectively measured outcome variable. Change in symptoms and the 15D-Quality of Life tool were used as subjective measurements.

MEASUREMENTS AND MAIN RESULTS

The lifestyle intervention was found to effectively reduce body weight (-10.7 +/- 6.5 kg; body mass index, -3.5 +/- 2.1 [mean +/- SD]). There was a statistically significant difference in the mean change in AHI between the study groups (P = 0.017). The adjusted odds ratio for having mild OSA was markedly lowered (odds ratio, 0.24 [95% confidence interval, 0.08-0.72]; P = 0.011) in the intervention group. All common symptoms related to OSA, and some features of 15D-Quality of Life improved after the lifestyle intervention. Changes in AHI were strongly associated with changes in weight and waist circumference.

CONCLUSIONS

VLCD combined with active lifestyle counseling resulting in marked weight reduction is a feasible and effective treatment for the majority of patients with mild OSA, and the achieved beneficial outcomes are maintained at 1-year follow-up.

Cytokine changes after surgical treatment of obstructive sleep apnoea syndrome

Obstructive sleep apnoea syndrome (OSAS) is associated with inflammatory processes and elevated plasma cytokines. This study assesses the effect of surgery in cytokine levels of OSAS patients. A total of 24 male patients with mild to moderate OSAS, confirmed with polysomnography underwent septoplasty and uvulo-palato-pharyngoplasty in a period of a year. Control group consisted of 12 overweighted subjects and 15 obese subjects. Peripheral venous blood was collected from each patient 1 week before surgical treatment and 6 months postoperatively. Spontaneous production of tumour necrosis factor (TNF-a) by monocytes and serum levels of IL-1beta and IL-6 were investigated. Control subjects were also examined for the same pro-inflammatory cytokines. Production of TNF-a and IL-6 were significantly elevated in OSAS patients and obese controls compared with overweighted control subjects (p < 0.05). Serum levels of IL-1beta did not differ among the study groups. Preoperative cytokine values were significantly correlated with the preoperative body mass index (BMI) and the apnoea/hypopnoea index (AHI) in OSAS patients. Surgery resulted a significant reduction in the TNF-a and IL-6 values of the study group. Decrease in cytokine level was strongly correlated with the AHI decrease. The postoperative relative percentage change of IL-6 values was significantly higher than this of TNF-a (p < 0.001). Surgical management of mild to moderate OSAS leads to a significant reduction in TNF-a and IL-6 values. Our data indicate that AHI is an independent risk factor of systemic inflammation; however it affects cytokines to a lesser degree compared with the BMI.