Overnight Changes in Lung Function of Obese Patients with Obstructive Sleep Apnoea

Prevalence of and factors associated with likely obstructive sleep apnea in individuals with airflow limitation

Introduction

Obstructive sleep apnea (OSA) is frequently associated with airflow limitation (AFL). However, information on the prevalence of and factors associated with likely OSA in individuals with AFL in Korea is limited.

Methods

Data from the 2019 Korea National Health and Nutrition Examination Survey (KNHANES) were used, and 3,280 individuals (2,826 individuals without AFL and 454 individuals with AFL) were included. AFL was defined as forced expiratory volume in 1 s (FEV1)/forced vital capacity (FVC) < 0.7. A score ≥ 5 on the STOP-BANG questionnaire was used to identify individuals with likely OSA. The prevalence of likely OSA was compared between individuals with and without AFL. In addition, factors associated with likely OSA in individuals with AFL were evaluated using multivariable logistic regression analysis.

Results

Of 3,280 individuals, 13.8% had an AFL. The prevalence of likely OSA was significantly higher in individuals with AFL than in individuals without AFL (9.2% vs. 5.0%, p = 0.014). Among 454 individuals with AFL, obesity (adjusted odds ratio [aOR] = 14.78, 95% confidence interval [CI] = 4.20-52.02) was most strongly associated with likely OSA, followed by heavy alcohol consumption (aOR = 4.93, 95% CI = 1.91-12.70), hypertension (aOR = 4.92, 95% CI = 1.57-15.46), overweight (aOR = 4.71, 95% CI = 1.76-12.64), college graduate (aOR = 4.47, 95% CI = 1.10-18.22), and history of pulmonary tuberculosis (aOR = 3.40, 95% CI = 1.06-10.96).

Conclusion

In Korea, approximately 1 in 10 individuals with AFL had likely OSA. Overweight and obesity, heavy alcohol consumption, high educational level, hypertension, and history of pulmonary tuberculosis were associated with likely OSA in individuals with AFL.

The efficacy of bariatric surgery on pulmonary function and sleep architecture of patients with obstructive sleep apnea and co-morbid obesity: a systematic review and meta-analysis

Obstructive sleep apnea (OSA) is highly prevalent in patients with morbid obesity. There is a growing interest in the role of bariatric surgery in OSA management. This study aims to evaluate the therapeutic efficacy of bariatric surgery on changes in pulmonary function and sleep architecture. Studies of patients with OSA that underwent bariatric surgery were searched in 4 different databases (PubMed, Cochrane, Web of Science, and Embase) until October 31, 2022. We identified studies evaluating the efficacy of surgical intervention on primary outcomes (body mass index [BMI] and apnea-hypopnea index [AHI]) and secondary outcomes such as forced vital capacity (FVC), forced expiratory volume in the first second (FEV1), FEV1/FVC, oxygen desaturation index (ODI), T90, mean oxygen saturation (SpO2), nadirSpO2, sleep efficiency (SE), N1%, N2%, N3%, rapid eye movement (REM%), arousal index, Epworth sleepiness scale (ESS), neck circumference, waist circumference, and weight. A total of 24 eligible studies were finally chosen. Risk of bias assessed through funnel plots was collected and analyzed via random effects meta-analyses. There were significant reductions in BMI and AHI after bariatric surgery induced weight loss. Accordingly, improvement in FVC, meanSpO2, nadirSpO2, SE, N3%, REM%, and ESS were observed compared with baseline. Patients with OSA also exhibit lower ODI, T90, arousal index, neck circumference, waist circumference, and weight after treatment. Bariatric surgery has beneficial effects on patients with OSA and obesity, particularly with morbid obesity. Surgical weight loss significantly eliminates apnea-hypopnea events, reduces weight, increases oxygen saturation, N3 and REM sleep stage, reduces sleep fragmentation, and improves pulmonary functions with augmented FVC.

Pulmonary Function Test and Obstructive Sleep Apnea Hypopnea Syndrome in Obese Adults: A Retrospective Study

Objective

We explore risk factors related to severe obstructive sleep apnea (OSA) in obese patients, including pulmonary ventilation function, diffusion function, and impulse oscillometry (IOS) data.

Methods

The medical records of 207 obese patients who were prepared to undergo bariatric surgery in a hospital from May 2020 to September 2021 were retrospectively reviewed. Polysomnography (PSG), pulmonary ventilation function, diffusion function, and IOS parameters were collected according to the ethical standards of the institutional research committee (registration number: KYLL-202008-144). Logistic regression analysis was used to analyze the related independent risk factors.

Results

There were significantly statistical difference in a number of pulmonary ventilation and diffusion function parameters among the non-OSAHS group, the mild-to-moderate OSA group, and the severe OSA group. However, only airway resistance parameters R5%, R10%, R15%, R20%, R25%, and R35% increased with increasing OSA severity and were positively correlated with apnea hypopnea index (AHI). Age (P = 0.012, 1.104 (1.022, 1.192)), body mass index (P< 0.0001, 1.12 (1.057, 1.187)), gender (P = 0.003, 4.129 (1.625, 10.49)), and R25% (P = 0.007, 1.018 (1.005, 1.031)) were independent risk factors for severe OSA. In patients aged 35 to 60, RV/TLC (P = 0.029, 1.272 (1.025, 1.577)) is an independent risk factor for severe OSA.

Conclusion

R25% was an independent risk factor for severe OSA in obese individuals, while RV/TLC was also an independent risk factor in those aged 35 to 60. Pulmonary function tests (PFTs), particularly IOS levels, are recommended to assess severe OSA in obese patients.

Effect of Short-Term Treatment with Continuous Positive Airway Pressure on Cardiopulmonary Exercise Tolerance, Pulmonary and Cardiac Function in Patients with Obstructive Sleep Apnea

Background: Obstructive sleep apnea (OSA) is a condition with a high prevalence, linked to an increased risk of cardiovascular disease as well as increased morbidity and death. CPAP is currently considered the "gold standard" treatment for OSA, but more thorough research and testing are required to assess its efficacy on cardiopulmonary function. Objectives: To evaluate pulmonary function of OSA patients, cardiopulmonary exercise tolerance test (CPET) performance, cardiac magnetic resonance imaging (MRI) parameters, and polysomnographic changes before and after 3 months of CPAP therapy. Materials and methods: A total of 34 patients diagnosed with moderate or severe OSA, as well as 17 patients as a control group for the evaluation of the cardiac MRI, were included in this study. All the subjects were obese (body mass index (BMI) > 30 kg/m2). Lung function tests, CPETs, cardiac MRIs, and polysomnography were performed at the time of the study's enrolment before the initiation of the CPAP therapy and after 3 months of the CPAP treatment. Results: The patients' VO2max during the CPAP treatment tended to increase, but no statistical significance was found (before treatment it was 17.52 ± 3.79 mL/kg/min and after 3 months of treatment, it was 18.6 ± 3,4 mL/kg/min; p = 0.255). The CPAP treatment had positive effects on pulmonary ventilation at the anaerobic threshold (VEAT): 44.51 L/min (43.21%) during the baseline visit and 38.60 L/min (37.86%) after the 3-month treatment period (p = 0.028). The ventilator equivalent for the carbon dioxide slope (VE/VCO2) at peak exercise decreased from 23.47 to 20.63 (p = 0.042). The patients' pulmonary function tests were without abnormalities and did not change after treatment. When assessing cardiac the MRIs, the RV ejection fraction was lower in the OSA group compared to that of the control subjects (53.69 ± 8.91 and 61.35 ± 9.08, p = 0.016). Both LA and RA global longitudinal strains (GLS) improved after 3 months of treatment with CPAP (20.45 ± 7.25 and 26.05 ± 14.00, p = 0.043; 21.04 ± 7.14 and 26.18 ± 7.17, p = 0.049, respectively). Additionally, it was found that CPAP therapy led to statistical improvements in RV end-diastolic volume (164.82 ± 32.57 and 180.16 ± 39.09, p = 0.042). The AHI and oxygen desaturation index (ODI) significantly changed after 3 months of the initiation of the CPAP treatment (p = 0.049 and p = 0.001, respectively). The REM sleep duration decreased, while the duration of non-REM sleep increased after treatment initiation with CPAP (p = 0.016 and p = 0.017, respectively). Conclusions: Short-term CPAP treatment improves pulmonary ventilation, sleep efficiency, and sleep architecture. Significant alterations in both atrias' GLS and RV end-diastolic volume were observed after 3 months of treatment. Longer-term follow-up and a larger patient sample are needed to confirm the reproducibility of our results.

Home Respiratory Polygraphy and Spirometry in Normal Weight and Children with Obesity Suspected for Obstructive Sleep Apnea Syndrome: Are There Any Associations?

Aim

It is known that children and adolescents with obesity are more prone to obstructive sleep apnea syndrome (OSAS) and that their lung function may show some disturbance. Literature is scarce about potential associations; therefore, we aimed to study the relationship between OSAS, lung function, and adiposity in a population of children suspected of OSAS. Material and Methods. We performed home respiratory polygraphy and spirometry in all subjects. The relationships between body mass index z-score (zBMI), polygraphy, and spirometry data were analyzed.

Results

We recruited 81 subjects aged between 5 and 16 years, 63% being obese. 43.2% of subjects were diagnosed with OSAS (32.1% mild, 4.9% moderate, and 6.2% severe). We found no correlation between respiratory polygraphy and the zBMI. The mean spirometric value FEV₁, FVC, and FEV₁/FVC ratio z's were normal in all subjects, whereas FVC z's and FEV₁/FVC ratio z's were significantly positively related for obesity and negatively for normal weight (p < 0.05). FEV₁ z's was inversely correlated to the percentage of analyzed time passed below 90% of SpO₂ (r = -0.224, p = 0.044). All subjects with FEV₁ (n = 8) and/or FVC (n = 9) z's below the lower limit for normal (LLN) had an AHI ≥ 1 (FEV₁: p = 0.001; FVC: p < 0.001), especially subjects with normal weight (FEV₁: p = 0.003; FVC: p = 0.010).

Conclusion

When comparing normal-weight children and adolescents with obesity, the prevalence of OSAS but not spirometric values was strongly related to BMI z-score, probably because obesity engenders advanced puberty and an accelerated growth spurt. FEV₁ was more frequently <LLN in normal-weight children, while obese subjects presented low FEV₁/FVC ratio z's and FEF_25-75% z's. Moreover, all subjects with abnormal spirometric values were suffering from at least mild OSAS, again more frequently in normal-weight subjects.

Asthma and obstructive sleep apnoea in adults and children - an up-to-date review

Obstructive sleep apnoea (OSA) and asthma are two common respiratory disorders in children and adults. Apart from common risk factors, such as obesity, gastroesophageal reflux disease and allergic rhinitis, emerging evidence suggest that the two diseases may complicate the clinical course of each other. On one hand, OSA modifies asthmatic airway inflammation and is associated with poor asthma control. On the other hand, asthma and its medications increase the collapsibility of the upper airways contributing to the development and worsening of OSA. The overnight respiratory symptoms of OSA and asthma are often similar, and an inpatient polysomnography is often necessary for a proper diagnosis, especially in children. Continuous positive pressure, the gold standard treatment for OSA can improve asthma control in patients suffering from both diseases. However, there is limited evidence how anti-asthma medications act in the same patients. Nevertheless, adenotonsillectomy seems to be effective in children with concomitant asthma and OSA. This review summarises the evidence for the bidirectional link between asthma and OSA, focuses on diagnostic and therapeutic challenges and highlights the need for further research.

Changes in Exercise Capacity of Patients With Obstructive Sleep Apnea Following Treatment With Continuous Positive Airway Pressure

Introduction: Patients with obstructive sleep apnea (OSA) frequently complain of fatigue during exercise. Treatment with continuous positive airway pressure (CPAP) ameliorates OSA-related symptoms and may reduce the burden of OSA on coexistent diseases. However, the role of CPAP on exercise capacity in OSA has not been fully investigated.

Aim: The aim of this study is to assess exercise capacity in a group of newly diagnosed OSA patients, without known comorbidities, following treatment with CPAP.

Methods: Consecutively diagnosed OSA patients by polysomnography completed the International Physical Activity Questionnaire (IPAQ) and underwent cardiopulmonary exercise testing (CPET) and pulmonary function testing at baseline of OSA diagnosis three months after adherence to CPAP treatment.

Results: A total of 40 OSA patients (Apnea-Hypopnea Index (ΑΗΙ)>15 events/hour) of whom 29 (72.5%) males with an average age of 42±2.5 years were enrolled in the study. OSA patients had a mean peak oxygen uptake (V̇O₂) value of 40.3 ±8.4 ml/kg/min (77.7±15%), which was improved after three months on CPAP treatment, 47.6±7.9 ml/kg/min (92.9±10.5%). (p=0.002). In addition, patients’ mean work (W) value increased significantly from baseline to three months of treatment with CPAP (101.5±30 watts vs 78.6±18.5 watts. p=0.015, respectively). There were no significant differences in terms of physical activity, as noted in IPAQ, before and after OSA therapy (p=0.075).

Conclusions: In the present study, OSA is associated with impaired exercise capacity, which seems to be improved after short-term treatment with PAP. Further evidence is warranted to elucidate whether CPET could be routinely used to monitor treatment responses of OSA with CPAP.

A community study of the risk for obstructive sleep apnea and respiratory inflammation in an adult Chinese population

Objectives: We aimed to investigate the relationship between obstructive sleep apnea (OSA) risk and respiratory inflammation evaluated by the exhaled breath condensate (EBC) interleukin-6 (IL-6) and plasma surfactant protein-D (SP-D), based on the Berlin questionnaire (BQ) screening values in an adult, urban community in Beijing, China.Methods: Volunteers aged >40 years were recruited from the Shichahai community of central Beijing (Registration number: NCT04832711). Their general information and disease history were recorded. OSA risk was assessed using the BQ. IL-6 in EBC and plasma SP-D were d etected by enzyme-linked immunoassay through specimens collected while fasting. The differences in IL-6 and SP-D values between high-risk and low-risk groups for OSA were compared, and the factors affecting their values were analyzed.Results: Among 1,239 participants, 18.8% of participants were in the high-risk group. There were more participants with higher body mass index, chronic hypertension, coronary heart disease, and diabetes in the high-risk group than in the low-risk group (P < 0.05). There were no significant differences in EBC IL-6 and plasma SP-D between the high- and low-OSA risk groups (p > 0.05). After adjustment for age, sex and chronic comorbidities, multivariate logistic regression showed that there was no correlation between risk of OSA and IL-6 in EBC. However, the risk of OSA (odds ratio [OR] [95% CI]: 1.69 [1.15,2.48]; β = 0.522) and BMI (OR [95%CI]: 0.94 [0.91,0.98]; β = -0.061) were independently associated with plasma SP-D level (p < 0.05 for both). Stratification analysis showed that OSA risk were independently associated with plasma SP-D levels in participants <65 years, or men, or participants with BMI<25.Conclusion: This study showed that plasma SP-D, an inflammation biomarker, was associated with risk of OSA and BMI in a Chinese central urban community.The relationship between the risk of OSA and respiratory inflammation in community populations needs to be further evaluated.

Influence of coexistence of mild OSA on airway mucus hypersecretion in patients with COPD

PURPOSE

The coexistence of chronic obstructive pulmonary disease (COPD) and obstructive sleep apnea (OSA) can cause multiple system damage, and the main physiological mechanisms are continuous hypoxia and intermittent hypoxia (IH). Airway mucus hypersecretion is an important clinical feature of COPD, which can cause a progressive decline of lung function, acute COPD aggravation, and disease progression. The purpose of our study is to determine the influence of the coexistence of mild OSA on airway mucus hypersecretion.

PATIENTS AND METHODS

Clinical data and airway epithelial samples were collected. The average fluorescence intensity of MUC5AC and the number of goblet cells were measured through immunofluorescence staining. MUC5AC expression was measured in human bronchial epithelial (HBE) cells exposed to normoxia, IH, particulate matter (PM), and PM+IH using real-time quantitative polymerase chain reaction and western blotting.

RESULTS

FEV1% pred and FEV1/FVC were higher in patients with COPD-OSA overlap syndrome(OS) than in patients with COPD alone. Patients with OS had less sputum volume than patients with COPD alone.MUC5AC expression and the number of goblet cells in the airway epithelium in the COPD alone group were significantly higher than those in the OS groups. The PM+IH group had lower MUC5AC mRNA and protein expression in HBE cells than the PM group.

CONCLUSIONS

The coexistence of mild OSA may reduce goblet cell proliferation and MUC5AC expression in the airway epithelium of patients with COPD. Mild IH inhibited PM-induced up-regulation of MUC5AC expression in the mRNA and protein levels in HBE cells.

The Burden of Associated Comorbidities in Patients with Obstructive Sleep Apnea-Regional Differences in Two Central-Eastern European Sleep Centers

Background: Obstructive sleep apnea (OSA) is usually associated with cardiovascular and cerebrovascular disease, metabolic syndrome and depression. Data on relevant OSA-associated comorbidities in Central–European populations are scarce. The aim of this study was to compare the prevalence of comorbidities in two OSA cohorts from Hungary and Romania. Methods: Data from 588 (282 from Hungary, 306 from Romania) untreated patients with OSA were retrospectively analyzed. The prevalence rates of hypertension, diabetes, dyslipidemia, allergic rhinitis, asthma, chronic obstructive pulmonary disease (COPD), osteoporosis, cerebrovascular and cardiovascular disease, arrhythmia and depression were compared between the two populations following adjustment for demographics, body mass index, smoking history, comorbidities and sleep parameters. Results: The prevalence rates of hypertension, arrhythmia, cerebrovascular and cardiovascular disease, diabetes and COPD in the whole study population were directly related to the severity of OSA. We found an inverse correlation between the prevalence of osteoporosis and OSA severity (all p < 0.05). Following adjustment, the prevalence of dyslipidemia was higher in the Hungarian cohort, whilst the prevalence of asthma, cardiovascular and cerebrovascular diseases was higher in the Romanian cohort (all p < 0.05). Conclusions: There was no difference in the prevalence rate of most comorbidities in patients with OSA from the two cohorts, except for dyslipidemia, asthma, cardiovascular and cerebrovascular disease.

Effects of chronic intermittent hypoxia caused by obstructive sleep apnea on lipopolysaccharide-induced acute lung injury

AIM OF THE STUDY

Obstructive sleep apnea (OSA) is a common disease associated with significant morbidity and mortality. Sleep quality is an important issue; some patients with acute lung injury (ALI) have underlying OSA. However, the potential influences of OSA on ALI have not been reported until now. In this study, we evaluated the impact of preceding intermittent hypoxia (IH), a typical characteristic of OSA, on lipopolysaccharide (LPS)-induced ALI in a mouse model.

METHODS

C57BL/6J mice were randomly divided into four groups: room air-control (RA-CTL), intermittent hypoxia-control (IH-CTL), room air-lipopolysaccharide (RA-LPS), and intermittent hypoxia-lipopolysaccharide (IH-LPS) groups. The mice were exposed to RA or IH (20 cycles/h, FiO₂ nadir 7 ± 0.5%, 8 h/day) for 30 days. The LPS groups received intratracheal LPS on day 28.

RESULTS

The IH-LPS group tended to exhibit more severe inflammation, fibrosis, and oxidative stress compared to the other groups, including the RA-LPS group. Total cell, neutrophil, and eosinophil counts in bronchoalveolar lavage fluid increased significantly in the IH-LPS group compared to the RA-LPS group. Compared to the RA-LPS group, the hydroxyproline level increased significantly in the IH-LPS group. In addition, the IH-LPS group exhibited significantly more terminal deoxynucleotidyl transferase dUTP nick end labeled-positive cells compared to the RA-LPS group.

CONCLUSIONS

We found that prior IH may negatively impact LPS-induced ALI in a mouse model. This result suggests that ALI in patients with OSA may be more of a concern. Further research into the mechanisms underlying the effects of IH on ALI is needed.

CPAP Effect on Cardiopulmonary Exercise Testing Performance in Patients with Moderate-Severe OSA and Cardiometabolic Comorbidities

Background and Objectives: Obstructive sleep apnea (OSA) is associated with daytime somnolence, cognitive impairment and high cardiovascular morbidity and mortality. Obesity, associated cardiovascular comorbidities, accelerated erythropoiesis and muscular mitochondrial energetic dysfunctions negatively influence exercise tolerance in moderate-severe OSA patients. The cardiopulmonary exercise testing (CPET) offers an integrated assessment of the individual's aerobic capacity and helps distinguish the main causes of exercise limitation. The purpose of this study is to evaluate the aerobic capacity of OSA patients, before and after short-term continuous positive airway pressure (CPAP). Materials and Methods: Our prospective study included 64 patients with newly diagnosed moderate-severe OSA (apnea hypopnea index (AHI) 39.96 ± 19.04 events/h) who underwent CPET before and after CPAP. Thirteen patients were unable to tolerate CPAP or were lost during follow-up. Results: 49.29% of our patients exhibited a moderate or severe decrease in functional capacity (Weber C or D). CPET performance was influenced by gender but not by apnea severity. Eight weeks of CPAP induced significant improvements in maximal exercise load (Δ = 14.23 W, p = 0.0004), maximum oxygen uptake (Δ = 203.87 mL/min, p = 0.004), anaerobic threshold (Δ = 316.4 mL/min, p = 0.001), minute ventilation (Δ = 5.1 L/min, p = 0.01) and peak oxygen pulse (Δ = 2.46, p = 0.007) as well as a decrease in basal metabolic rate (BMR) (Δ = -8.3 kCal/24 h, p = 0.04) and average Epworth score (Δ = -4.58 points, p < 0.000001). Conclusions: Patients with moderate-severe OSA have mediocre functional capacity. Apnea severity (AHI) was correlated with basal metabolic rate, resting heart rate and percent predicted maximum effort but not with anaerobic threshold or maximum oxygen uptake. Although CPET performance was similar in the two apnea severity subgroups, short-term CPAP therapy significantly improved most CPET parameters, suggesting that OSA per se has a negative influence on effort capacity.

Snoring and nocturnal reflux: association with lung function decline and respiratory symptoms

Introduction

The study aim was to examine the association of snoring and nocturnal gastro-oesophageal reflux (nGOR) with respiratory symptoms and lung function, and if snoring and/or nGOR associated with a steeper decline in lung function.

Methods

Data from the third visit of the European Community Respiratory Health Survey (ECRHS) was used for cross-sectional analysis. Pre- and post-bronchodilator spirometry was performed, and information on sleep, nGOR and respiratory symptoms was collected (n=5715). Habitual snoring and nGOR were assessed by questionnaire reports. Pre-bronchodilator spirometry from ECRHS I, II and III (20 years follow-up) were used to analyse lung function changes by multivariate regression analysis.

Results

Snoring and nGOR were independently associated with a higher prevalence of wheeze, chest tightness, breathlessness, cough and phlegm. The prevalence of any respiratory symptom was 79% in subjects with both snoring and nGOR versus 56% in those with neither (p<0.001). Subjects with both snoring and nGOR had more frequent exacerbations (adjusted prevalence 32% versus 19% among "no snoring, no nGOR", p=0.003). Snoring but not nGOR was associated with a steeper decline in forced expiratory volume in 1 s over 10 years after adjusting for confounding factors (change in % predicted -5.53, versus -4.58 among "no snoring", p=0.04) and forced vital capacity (change in % predicted -1.94, versus -0.99 among "no snoring", p=0.03).

Conclusions

Adults reporting both habitual snoring and nGOR had more respiratory symptoms and more frequent exacerbations of these symptoms. Habitual snoring was associated with a steeper decline in lung function over time.

Current opinions for the management of asthma associated with ear, nose and throat comorbidities

Ear, nose and throat (ENT) comorbidities are common in patients with asthma and are frequently associated with poorer asthma outcomes. All these comorbidities are "treatable traits" in asthma. Identification and management of these disorders may spare medication usage and contribute to improved asthma control and quality of life, and a decrease in exacerbation rates.This review summarises recent data about the prevalence, clinical impact and treatment effects of ENT comorbidities in asthma including allergic rhinitis, chronic rhinosinusitis with and without nasal polyposis, aspirin-exacerbated respiratory disease, obstructive sleep apnoea and vocal cord dysfunction.Many of these comorbidities are possible to be managed by the pulmonologist, but the collaboration with the ENT specialist is essential for patients with chronic rhinosinusitis or vocal cord dysfunction. Further rigorous research is needed to study the efficacy of comorbidity treatment to improve asthma outcomes, in particular with the development of biotherapies in severe asthma that can also be beneficial in some ENT diseases.

Forced expiratory volume in one second: A novel predictor of work disability in subjects with suspected obstructive sleep apnea

Whether the association of work disability with obstructive sleep apnea (OSA) is mainly due to the disease, i.e. the number and frequency of apneas-hypoapneas, or to coexisting factors independent from the disease, is not well-established. In this study, we aim to evaluate work ability in a group of subjects undergoing OSA workup and to identify the major contributors of impaired work ability. In a cross-sectional study, we enrolled 146 consecutive subjects who have been working for the last five years and referred to the sleep disorders outpatients' clinic of the University-Hospital of Ferrara, Italy, with suspected OSA. After completing an interview in which the Work Ability Index (WAI) and the Epworth Sleepiness Scale (ESS) questionnaires were administered to assess work ability and excessive daytime sleepiness, respectively, subjects underwent overnight polysomnography for OSA diagnosing and spirometry. Of the 146 subjects, 140 (96%) completed the tests and questionnaires and, of these, 66 exhibited work disability (WAI < 37). OSA was diagnosed (apnea-hypopnea index ≥ 5) in 45 (68%) of the 66 subjects. After controlling for confounders, a lower level of forced expiratory volume at 1 second (FEV1), [odds ratio 0.97 (95% CI 0.95-1.00)], older age [1.09 (95% CI 1.03-1.15)], excessive daytime sleepiness [3.16 (95% CI 1.20-8.34)] and a worse quality of life [0.96 (95% CI 0.94-1.00)], but not OSA [1.04 (95% CI 0.41-2.62)], were associated with work disability. Patients with a higher number of diseases, in which OSA was not included, and a lower quality of life had an increased probability of absenteeism in the previous 12 months. In subjects with suspected OSA, FEV1 can be an important predictor of work disability.

[Alterations of respiratory resistance in patients with obstructive sleep apnea hypopnea syndrome]

OBJECTIVE

To evaluate the association between the components of airway resistance and severity of obstructive sleep apnea hypopnea syndrome (OSAHS).

METHODS

A total of 234 patients with snoring during sleep underwent full-night polysomnography in our center between January, 2015 and September, 2017. According to the apnea-hypopnea index (AHI) scores, the patients were divided into non-OSAHS group (AHI scores <5), mild or moderate OSAHS group (5-30) group, and severe OSAHS group (>30). The pulmonary function and respiratory resistance of the patients were assessed using spirometry and impulse oscillometry, respectively, and the correlation between the parameters of respiratory resistance and the severity of AHI were analyzed.

RESULTS

The non-OSAHS, mild or moderate OSAHS, and severe OSAHS groups consisted of 31, 90 and 113 patients, respectively. The patients with severe OSAHS had significantly higher levels of respiratory resistance at 5 Hz (R5) and 20 Hz (R20), FEF_50% and MMEF than those in the other two groups (P<0.05). Bivariate correlation analysis identified positive correlations of R5 (r=0.259, P=0.000), R20 (r=0.298, P=0.000) and FEF_50% (r=0.176, P=0.007) with AHI scores of the patients.

CONCLUSION

Patients with OSAHS have increased respiratory resistance in the large airways and compensatory reduction in small airway resistance.

Circulating Survivin Levels in Obstructive Sleep Apnoea

INTRODUCTION

Obstructive sleep apnoea (OSA) is characterised by a low-grade systemic and airway inflammation; however, the regulatory mechanisms of inflammation are poorly explored. Survivin (Birc5) is an anti-apoptotic protein which inhibits Type 1 inflammation; however, this molecule has not been investigated in OSA.

METHODS

Forty-five patients with OSA and 31 non-OSA control subjects were involved. Venous blood was collected for plasma survivin measurements before and after diagnostic overnight polysomnography. Plasma survivin levels were compared between the two groups and correlated to OSA severity and comorbidities.

RESULTS

Plasma survivin levels were lower in OSA in the evening (27.6 ± 89.9 vs. 108.3 ± 161.2 pg/ml, p < 0.01) and in the morning (17.4 ± 48.6 vs. 36.4 ± 69.2 pg/ml, p = 0.02) compared to the control group. This OSA-related decrease was also present when only the non-obese patients were analysed. Significant indirect relationships were observed between plasma survivin levels and measures of OSA severity such as the apnoea-hypopnoea index (r = - 0.45) or oxygen desaturation index (r = - 0.40, both p < 0.01); however, when adjusting to BMI, these became insignificant (p > 0.05). Low plasma survivin concentrations were associated with high BMI (r = - 0.35), high CRP (r = - 0.31), low HDL cholesterol (r = 0.24) and high triglyceride levels (r = - 0.24, all p < 0.05).

CONCLUSION

Plasma survivin levels are reduced in OSA, relate to disease severity, and are associated with high CRP levels. This suggests an impaired immunoregulation in this disorder which needs to be studied in further detail.

Role of lung volume and airway inflammation in obstructive sleep apnea

Obstructive sleep apnea (OSA) is a prevalent disorder that affects not only the upper airways but also the intrathoracic airways. In this review, we summarize the results of studies on lung function and airway inflammation. We provide evidence that the alterations in intrathoracic airways observed in OSA are not purely consequences of mechanical trauma and oxidative stress during apneic events but have a causal role in the structural changes associated with OSA and increasing severity of this disorder.

Perception of circadian variation of symptoms in Chinese patients with chronic obstructive pulmonary disease

BACKGROUND

Although, the variable pattern of asthmatic symptoms is well recognized, little is known about the respiratory symptoms variability in patients of chronic obstructive pulmonary disease (COPD). The present study evaluated the variability of the respiratory symptoms in a day and their influence on the daily activities in a cohort of Chinese COPD patients.

METHODS

An observational cross-sectional study was conducted in 11 medical centers of China. Participants were outpatient ≥40 years old with stable COPD, post-bronchodilator forced expiratory volume in 1 second (FEV1) <80% predicted. Overall, data of 1,032 eligible patients were valid for final analysis.

RESULTS

Mean post bronchodilator FEV1 (predicted %) was 46.5%. Cough, expectoration and dyspnea were the most commonly observed symptoms (73.6%, 68.8% and 61.4%, respectively). Daily symptom variability was experienced by 50.2% of symptomatic patients. The wake up time in the morning was the worst and the most troublesome time during the day (39.3%), followed by the nighttime (21.3%). The morning activities were most affected by COPD symptoms. Multivariate analyses revealed that COPD assessment test (CAT) scores was the only factor correlated with patients' symptom variability [odds ratio (OR) =0.463, P<0.0001].

CONCLUSIONS

Patient-perceived symptoms vary during the day in Chinese COPD patients. They experience the greatest increase in respiratory symptoms early in the morning. This variation should be considered as a potential new target in the long-term COPD management.