Impact of sleep in COPD

Dupilumab improves sleep quality in chronic rhinosinusitis with nasal polyps

PURPOSE

Chronic rhinosinusitis with nasal polyps (CRSwNP) often alters sleep quality. Dupilumab emerged as an innovative and effective therapy for refractory/recurrent severe CRSwNP. The aim of this observational retrospective study was to evaluate the sleep quality in patients with CRSwNP who underwent treatment with dupilumab.

MATERIALS AND METHODS

Forty-five patients treated with dupilumab for CRSwNP were enrolled. Clinical parameters (age, sex, comorbidities, Nasal Polyp Score - NPS, Asthma Control Test - ACT), nasal cytology, quality of life (Sino Nasal Outcome Test 22 - SNOT-22), sleep quality (Pittsburgh Sleep Quality Index - PSQI, Epworth Sleepiness Scale - ESS), and risk of sleep apnea (STOP-BANG) were recorded before treatment (T0), and after 3 (T1), 6 (T2), and 12 months (T3).

RESULTS

NPS, ACT and SNOT-22 total score improved during treatment (p < 0.05). Meanwhile, all sleep parameters evaluated with SNOT-22, ESS and PSQI improved over time (p < 0.001), expect for PSQI Use of sleeping medications. Indeed, sleep drugs are rarely used before and during the treatment. The global sleep quality was classified as poor in 88.9 % of cases at T0 and decreased to 5.7 % at T3. A high risk of sleep apnea was revealed by the STOP-BANG in 68.9 % of cases at T0 and 2.8 % of patient at T3 (p < 0.001).

CONCLUSIONS

Dupilumab improves the sleep quality and reduce the risk of sleep apnea in patients with severe CRSwNP. Its favorable effect occurs within 3 months and is maintained during the treatment.

Does Obstructive Sleep Apnea Lead to Progression of Chronic Obstructive Pulmonary Disease

Chronic obstructive pulmonary disease (COPD) and obstructive sleep apnea (OSA) have important bidirectional relationships that influence the pathophysiology of each disorder. The slim hyperinflated "pink puffer" phenotype of COPD protects against OSA, whereas the heavier "blue bloater" phenotype predisposes to OSA by fluid retention. OSA may aggravate COPD by promoting airway inflammation. COPD-OSA overlap patients have lower quality of life and are at higher risk of cardiovascular comorbidity than either disorder alone due to greater nocturnal oxygen desaturation and sympathetic activation. Management of OSA with positive airway pressure improves COPD outcomes that include lower exacerbation rates compared to untreated patients.

Sleep disordered breathing: OSA-COPD overlap

INTRODUCTION

Sleep has important effects on breathing and gas exchange that may have negative consequences in patients with chronic obstructive pulmonary disease (COPD). COPD and obstructive sleep apnea (OSA) are highly prevalent and may coexist, which is referred to as the overlap syndrome.

AREAS COVERED

The probability of OSA-COPD overlap represents the balance of protective and promoting factors such as hyperinflation and fluid retention; thus, different clinical COPD phenotypes influence the likelihood of comorbid OSA. The clinical presentation of OSA-COPD overlap is nonspecific, and the diagnosis requires clinical awareness to identify patients needing overnight studies. Both COPD and OSA are associated with a range of overlapping physiological and biological disturbances including hypoxia and inflammation that contribute to cardiovascular comorbidities. The management of OSA-COPD overlap patients differs from those with COPD alone and the survival of overlap patients treated with positive airway pressure (PAP) is superior to those untreated.

EXPERT OPINION

The recognition of OSA-COPD overlap has important clinical relevance because of its impact on outcomes and management. Management of the overlap should address both sleep quality and disordered gas exchange. PAP therapy has demonstrated reductions in COPD exacerbations, hospitalizations, healthcare costs and mortality in overlap patients.

Interaction of BMI and respiratory status in obstructive sleep apnea, a cross-sectional COPD study

This cross-sectional study of 136 patients with chronic obstructive pulmonary disease (COPD) investigated the mechanism underlying overlap syndrome, defined as coexisting COPD and obstructive sleep apnea (OSA). OSA was defined as a respiratory event index (REI) ≥ 5 events/h, determined using type-3 portable monitors. The mean REI was 12.8 events/h. Most participants (60.1%) had mild OSA (REI: 5-15 events/h). The REI was positively correlated with forced expiratory volume in one second (%FEV1) (r = 0.33, p < 0.001), body mass index (BMI) (r = 0.24, p = 0.005), and fat-free mass index (r = 0.31, p = 0.005), and negatively correlated with residual volume divided by total lung capacity (r = -0.27, p = 0.003). Receiver-operating characteristic curve analysis revealed an optimal BMI cutoff of 21.96 kg/m2 for predicting moderate/severe OSA. A BMI ≥ 21.96 kg/m2 was associated with OSA among participants with %FEV1 ≥ 50%, but not those with %FEV1 < 50%. This study revealed an interaction between airflow limitation and hyperinflation, nutritional status, and OSA.

Day-night patterns in heart rate variability and complexity: differences with age and cardiopulmonary disease

STUDY OBJECTIVES

Heart rate variability (HRV) measures provide valuable insights into physiology; however, gaps remain in understanding circadian patterns in heart rate dynamics. We aimed to explore day-night differences in heart rate dynamics in patients with chronic cardiopulmonary disease compared with healthy controls.

METHODS

Using 24-hour heart rate data from patients with chronic obstructive pulmonary disease (COPD) and/or heart failure (n = 16) and healthy adult controls (older group: ≥50 years, n = 42; younger group: 20-49 years, n = 136), we compared day-night differences in conventional time and frequency domain HRV indices and a multiscale-entropy-based complexity index (CI1-20) of HRV among the 3 groups.

RESULTS

Twenty-four-hour HRV showed significant day-night differences (marked with "△") among younger healthy (mean age: 34.5 years), older healthy (mean age: 61.6 years), and cardiopulmonary patients (mean age: 68.4 years), including change in percentage of adjacent intervals that differ > 50 ms (△pNN50), high frequency (△HF), normalized low frequency (△nLF), ratio (△LF/HF), and △CI1-20. Among these, △LF/HF (2.13 ± 2.35 vs 1.1 ± 2.47 vs -0.35 ± 1.25; P < .001) and △CI1-20 (0.15 ± 0.24 vs 0.02 ± 0.28 vs -0.21 ± 0.27; P < .001) were significant in each pairwise comparison following analysis of variance tests. Average CI1-20 was highest in younger healthy individuals and lowest in cardiopulmonary patients (1.37 ± 0.12 vs 1.01 ± 0.27; P < .001). Younger healthy patients showed a heart rate complexity dipping pattern (night < day), older healthy patients showed nondipping, and cardiopulmonary patients showed reverse dipping (night > day).

CONCLUSIONS

As measures of 24-hour variability, traditional and complexity-based metrics of HRV exhibit large day-night differences in healthy individuals; these differences are blunted, or even reversed, in individuals with cardiopulmonary pathology. Measures of diurnal dynamics may be useful indices of reduced adaptive capacity in patients with cardiopulmonary conditions.

CITATION

Ma Y, Chang M-C, Litrownik D, Wayne PM, Yeh GY. Day-night patterns in heart rate variability and complexity: differences with age and cardiopulmonary disease. J Clin Sleep Med. 2023;19(5):873-882.

Supplemental oxygen and noninvasive ventilation

The respiratory system attempts to maintain normal levels of oxygen and carbon dioxide. However, airflow limitation, parenchymal abnormalities and dysfunction of the respiratory pump may be compromised in individuals with advanced COPD, eventually leading to respiratory failure, with reduced arterial oxygen tension (hypoxaemia) and/or increased arterial carbon dioxide tension (P aCO2 ; hypercapnia). Hypoxaemia may persist in individuals with severe COPD despite smoking cessation and optimisation of pharmacotherapy. Long-term oxygen therapy (LTOT) can improve survival in those with severe daytime hypoxaemia, whereas those with less severe hypoxaemia may only have improved exercise capacity and dyspnoea. Changes in respiratory physiology that occur during sleep further predispose to hypoxaemia, particularly in individuals with COPD. However, the major cause of hypoxaemia is hypoventilation. Noninvasive ventilation (NIV) may reduce mortality and need for intubation in individuals with COPD and acute hypercapnic respiratory failure. However, NIV may also improve survival and quality of life in individuals with stable, chronic hypercapnia and is now suggested for those with prolonged hypercapnia (e.g. P aCO2 >55 mmHg 2-6 weeks after hospital discharge) when clinically stable and after optimisation of medical therapy including LTOT if indicated. Many questions remain about the optimal mode, settings and goal of NIV therapy.

Chronic obstructive pulmonary disease and obstructive sleep apnoea overlap: co-existence, co-morbidity, or causality?

PURPOSE OF REVIEW

The chronic obstructive pulmonary disease and obstructive sleep apnoea overlap syndrome is associated with higher morbidity and mortality rates than either disease alone. There is evidence of a bidirectional relationship between the two conditions, with the overlap syndrome encompassing a spectrum of clinical phenotypes.

RECENT FINDINGS

This review examines the evidence for the various factors that determine the overlap syndrome, the impact overlap syndrome has on co-morbidities, and implications for diagnosis and treatment.

SUMMARY

The accurate diagnosis of the overlap syndrome is critical given its implications for treatment optimisation and reduction in healthcare utilisation and costs.

Sleep-onset time variability and sleep characteristics on weekday and weekend nights in patients with COPD

Objective:

To evaluate sleep-onset time variability, as well as sleep characteristics on weekday and weekend nights, in individuals with moderate-to-severe COPD.

Methods:

Sleep was objectively assessed by an activity/sleep monitor for seven consecutive nights in individuals with COPD. For analysis, individuals were divided into two groups according to sleep-onset time variability results, characterized by intrasubject standard deviation of sleep-onset time (SOT_V) ≥ 60 min or < 60 min.

Results:

The sample comprised 55 individuals (28 males; mean age = 66 ± 8 years; and median FEV₁ % of predicted = 55 [38-62]). When compared with the SOT_V<60min group (n = 24), the SOT_V≥60min group (n = 31) presented shorter total sleep time (5.1 ± 1.3 h vs. 6.0 ± 1.3 h; p = 0.006), lower sleep efficiency (73 ± 12% vs. 65 ± 13%; p = 0.030), longer wake time after sleep onset (155 ± 66 min vs. 115 ± 52 min; p = 0.023), longer duration of wake bouts (19 [16-28] min vs. 16 [13-22] min; p = 0.025), and higher number of steps at night (143 [104-213] vs. 80 [59-135]; p = 0.002). In general, sleep characteristics were poor regardless of the day of the week, the only significant difference being that the participants woke up about 30 min later on weekends than on weekdays (p = 0.013).

Conclusions:

Sleep-onset time varied over 1 h in a standard week in the majority of individuals with COPD in this sample, and a more irregular sleep onset indicated poor sleep quality both on weekdays and weekends. Sleep hygiene guidance could benefit these individuals if it is integrated with their health care.

Chronic Obstructive Pulmonary Disease Effect of Nonapnea Sleep Disorder on the Risk of Obesity: A Nationwide Population-Based Case-Control Study

Objectives: To investigate whether chronic obstructive pulmonary disease (COPD) affects nonapnea sleep disorder (NASD) on the risk of obesity. Materials and Methods: From 1 January 2000 to 31 December 2015, a total of 24,363 patients with obesity from the 2005 Longitudinal Health Insurance Database were identified; 97,452 patients without obesity were also identified from the same database. Multiple logistic regression was used to analyze the previous exposure risk of patients with obesity and NASD. A p value of <0.05 was considered significant. Results: The risk of developing obesity in patients with COPD is 3.05 times higher than that in patients without COPD. Patients with COPD with NASD had a 1.606-fold higher risk of developing obesity than those without NASD. Patients with obesity were more likely to be exposed to NASD than did those without obesity (adjusted odds ratio, 1.693; 95% confidence interval, 1.575−1.821, p < 0.001). Furthermore, the closeness of the exposure period to the index time was positively associated with the severity of obesity, with a dose−response effect. The exposure duration of NASD in patients with obesity was 1.693 times than that in those without obesity. Longer exposure durations were associated with more severe obesity, also with a dose−response effect. Conclusions: The COPD effect of NASD increases the subsequent risk of obesity, and the risk of obesity was determined to be significantly higher in patients with NASD in this case−control study. Longer exposure to NASD was associated with a higher likelihood of obesity, also with a dose−response effect.

Sleep-Related Breathing Complaints in Chronic Obstructive Pulmonary Disease

This review presents the normal physiologic changes in ventilation during sleep and how they can be detrimental to chronic obstructive pulmonary disease (COPD). Sleep-related breathing disorders (SRBDs) in COPD lead to higher morbidity and mortality if left unrecognized and untreated. The diagnosis of SRBDs requires a high index of suspicion, as symptoms may overlap with other sleep disorders. Mortality risk is improved when patients with COPD with OSA (overlap syndrome) are treated with positive airway pressure and when long-term nocturnal noninvasive ventilation is started on chronic stable hypercapnic COPD. Treatment of isolated nocturnal oxygen desaturation has not been associated with improved survival.

Review of the prevalence, pathogenesis and management of OSA-COPD overlap

PURPOSE

OSA-COPD overlap is an important and prevalent condition yet remains under-recognised among the vast majority of respiratory health professionals. Patients with OSA-COPD overlap experience more severe respiratory symptoms and worse quality of life, and the relative risk of exacerbations, hospitalisations, and mortality is higher than in either disease state alone.

METHODS

Electronic databases PUBMED and Google Scholar were searched for studies and academic papers that discussed OSA-COPD overlap. Relevant papers that discussed prevalence, pathophysiology, microbiome studies, treatment regimens and outcomes were included in this paper.

RESULTS

High-risk patients with either COPD or OSA should be screened for overlap syndrome as part of routine clinical practice. Screening questionnaires can identify high-risk patients with COPD who may benefit from formal polysomnography. Patients with OSA who are aged over 40 with a significant smoking history or environmental exposures have an increased pre-test probability of obstructive airway disease. The potential roles of gastro-oesophageal reflux disease and lung-gut microbiome are evolving and merit further investigation. A tailored approach to reach a timely diagnosis and thus optimisation of both conditions are key to management. CPAP is the primary therapy for OSA; however, patients with more advanced COPD, with daytime hypercapnia or severe nocturnal desaturations, may benefit from bilevel positive airway pressure.

CONCLUSION

Increased awareness, access to timely investigations and initiation of therapy will improve overall outcomes in OSA-COPD overlap by reducing hospitalisations for exacerbations of COPD and improve mortality rates.

The association between sleep quality, health status and disability due to breathlessness in chronic obstructive pulmonary disease patients

BACKGROUND

Chronic obstructive pulmonary disease (COPD) increases susceptibility to sleep disturbances. This study aimed to evaluate the association between COPD severity criteria with sleep quality.

METHODS

One hundred fifty-eight patients in Rasul Akram Hospital of Iran University of Medical Sciences, Tehran, Iran, from April 2019 to March 2021 diagnosed with COPD were examined using the Pittsburgh Sleep Quality Index (PSQI), COPD Assessment Test (CAT), modified Medical Research Council (mMRC) dyspnoea scale, spirometry and pulse oximetry.

RESULTS

Of 158 subjects, 125 patients were male (79%), and 33 were female (21%). The mean subject's age and FEV1/FVC ratio were 62.6 ± 11.5 and 65.6 ± 14.9%, respectively. The mean CAT scoring and Spo2 saturation reported 16.2 ± 7 and 91.5 ± 10.8%, respectively. The mean PSQI score was 8.2 ± 3.8. The association between PSQI score with FEV1 and FEV1/FVC ratio was not statistically significant (p = 0.64 and 0.58, respectively), whereas the association between PSQI scores with CAT score (p ˂ 0.0001, r²  = 0.51) and dyspnoea severity (p ˂ 0.0001, r²  = 0.29) were statistically significant. The patients with higher CAT score demonstrated poor sleep quality, particularly in longer sleep latency (p = 0.001, r²  = 0.056), bad subjective sleep quality (p ˂ 0.0001, r²  = 0.286), lower sleep efficiency (p = 0.002, r²  = 0.077), higher sleep disturbance (p ˂ 0.0001, r²  = 0.225), daytime dysfunction (p ˂ 0.0001, r²  = 0.259) and sleep medication intake times a week (p = 0.01, r²  = 0.069). Dyspnoea severity was attributed to bad subjective sleep quality (p ˂ 0.0001, r²  = 0.069), higher sleep disturbances (p = 0.005, r²  = 0.08), and daytime dysfunction (p ˂ 0.0001, r²  = 0.108).

CONCLUSION

The PSQI has a significant association with the CAT and mMRC for COPD patients and is linked to the disease's severity.

Sleep quality and architecture in COPD: the relationship with lung function abnormalities

OBJECTIVE

Impaired respiratory mechanics and gas exchange may contribute to sleep disturbance in patients with COPD. We aimed to assess putative associations of different domains of lung function (airflow limitation, lung volumes, and gas exchange efficiency) with polysomnography (PSG)-derived parameters of sleep quality and architecture in COPD.

METHODS

We retrospectively assessed data from COPD 181 patients ≥ 40 years of age who underwent spirometry, plethysmography, and overnight PSG. Univariate and multivariate linear regression models predicted sleep efficiency (total sleep time/total recording time) and other PSG-derived parameters that reflect sleep quality.

RESULTS

The severity of COPD was widely distributed in the sample (post-bronchodilator FEV1 ranging from 25% to 128% of predicted): mild COPD (40.3%), moderate COPD (43.1%), and severe-very severe COPD (16.6%). PSG unveiled a high proportion of obstructive sleep apnea (64.1%) and significant nocturnal desaturation (mean pulse oximetry nadir = 82.2% ± 6.9%). After controlling for age, sex, BMI, apnea-hypopnea index, nocturnal desaturation, comorbidities, and psychotropic drug prescription, FEV1/FVC was associated with sleep efficiency (β = 25.366; R2 = 14%; p < 0.001), whereas DLCO predicted sleep onset latency (β = -0.314; R2 = 13%; p < 0.001) and rapid eye movement sleep time/total sleep time in % (β = 0.085; R2 = 15%; p = 0.001).

CONCLUSIONS

Pulmonary function variables reflecting severity of airflow and gas exchange impairment, adjusted for some potential confounders, were weakly related to PSG outcomes in COPD patients. The direct contribution of the pathophysiological hallmarks of COPD to objectively measured parameters of sleep quality seems to be less important than it was previously assumed.

Audio source separation to reduce sleeping partner sounds: a simulation study

Objective.When recording a subject in an at-home environment for sleep evaluation or for other breathing disorder diagnoses using non-contact microphones, the breathing recordings (audio signals) can be distorted by sounds such as TV, outside noise, or air-conditioners. If two people are sleeping together, both may produce breathing/snoring sounds that need to be separated. In this study, we present signal processing and source separation algorithms for the enhancement of individual breathing/snoring audio signals in a simulated environment.Approach.We developed a computer simulation of mixed signals derived from genuine nocturnal recordings of 110 subjects. Two main source separation approaches were tested: (1) changing the basis vectors for the mixtures in the time domain (principal and independent component analysis, PCA/ICA) and (2) converting the mixtures to their time-frequency representations (degenerate un-mixing estimation technique, DUET). In addition to these source separation techniques, a beamforming approach was tested.Main results.The separation results with a reverberation time of 0.15 s and zero SNR between signals showed good performance (mean source to interference ratio (SIR): DUET = 12.831 dB, ICA = 3.388 dB, PCA = 4.452 dB), and for beamforming (SIR = -0.304 dB). To evaluate our source separation results, we propose two new measures: an evaluation measure based on a spectral similarity score (mel-SID) between the target source and its estimation (after separation) and a breathing energy ratio measure (BER). The results with the new proposed measures yielded comparable conclusions (mel-SID: DUET = 1.320, ICA = 2.732, PCA = 1.927, and beamforming = 2.590, BER: DUET = 10.241 dB, ICA = 0.270 dB, PCA = -2.847 dB, and beamforming = -1.151 dB), but better differentiated the differences between the performance of the algorithms. The DUET is superior on all measures. Its main advantage is that it only uses two microphones for separation.Significance. The separated audio signal can thus contribute to a more informed diagnosis of sleep-related and non-sleep-related diseases. The Institutional Review Committee of Soroka University Medical Center approved this study protocol (protocol number 10141) and all methods were performed in accordance with the relevant guidelines and regulations.

Acute effects of noninvasive ventilation on sleep physiology in patients with moderate to severe stable chronic obstructive pulmonary disease: a pilot study

OBJECTIVE/BACKGROUND

Changes in sleep architecture in patients with Chronic Obstructive Pulmonary Disease (COPD) can be explained by a combination of physiological changes in breathing during sleep, with impairment of respiratory mechanics and reduction of arterial oxygenation. This study aimed to evaluate the acute effects of noninvasive ventilation (NIV) - compared to spontaneous breathing - on sleep latency and stages, and on the occurrence of sleep-related respiratory events, nocturnal hypoxemia, and changes in heart rate (HR) in patients with moderate to severe stable COPD.

PATIENTS/METHODS

Patients completed two polysomnography (PSG) studies: one during spontaneous breathing and one while receiving NIV in bilevel mode and with backup respiratory rate (RR.) setting. Sleepware G3 software was used for the analysis of PSG and pressure, volume, and ventilator flow curves × time.

RESULTS

Participants were 10 female patients with a mean age of 68.1 ± 10.2 years. NIV during sleep decreased sleep onset latency (17 ± 18.8 min vs 46.8 ± 39.5 min; p = 0.02), increased REM sleep time (41.2 ± 24.7 min vs 19.7 ± 21.7 min; p = 0.03), and decreased the obstructive apnea index (OAI) (0 vs 8.7 ± 18.8; p = 0.01). Lower mean HR (66.6 ± 4.1 bpm vs 70.6 ± 5.9 bpm; p = 0.03) and lower maximum HR (84.1 ± 7.3 bpm vs 91.6 ± 7.8 bpm; p = 0.03) were observed in PSG with NIV.

CONCLUSIONS

The use of NIV in patients with moderate to severe stable COPD while they were sleeping increased REM sleep time and decreased sleep onset latency, the number of obstructive respiratory events, and the mean and maximum HR.

Long-term noninvasive ventilation in COPD: current evidence and future directions

Introduction: Long-term noninvasive ventilation (NIV) is an established treatment for end-stage COPD patients suffering from chronic hypercapnic respiratory failure. This is reflected by its prominent position in national and international medical guidelines. Areas covered: In recent years, novel developments in technology such as auto-titrating machines and hybrid modes have emerged, and when combined with advances in information and communication technologies, these developments have served to improve the level of NIV-based care. Such progress has largely been instigated by the fact that healthcare systems are now confronted with an increase in the number of patients, which has led to the need for a change in current infrastructures. This article discusses the current practices and recent trends, and offers a glimpse into the future possibilities and requirements associated with this form of ventilation therapy. Expert opinion: Noninvasive ventilation is an established and increasingly used treatment option for patients with chronic hypercapnic COPD and those with persistent hypercapnia following acute hypercapnic lung failure. The main target is to augment alveolar hypoventilation by reducing P_aCO₂ to relieve symptoms. Nevertheless, when dealing with severely impaired patients, it appears necessary to switch the focus to patient-related outcomes such as health-related quality of life.

The deleterious effects of chronic obstructive pulmonary disease and obstructive sleep apnea: pathophysiology and implications on treatment

Background

Chronic obstructive pulmonary disease (COPD) and obstructive sleep apnea (OSA) are both common in the adult population. The coexistence and association of both COPD and OSA have been described as the overlap syndrome. The scope of the present review is to address the magnitude, pathophysiology, clinical presentations, and the deleterious consequences of the coexistence of COPD and OSA in the same patient as well as the current management and treatment options of this association.

Main body of abstract

Epidemiological studies showed a prevalence of the overlap syndrome of up to 1% of the adult population. However, various studies agreed that this association is due to the fact that both COPD and OSA are common rather than an interaction of pathophysiology between the two affections. Nevertheless, sleep may cause adverse effects on breathing and lung functions. While these effects can be neglected in otherwise healthy individuals, they can lead in contrast to disastrous clinical outcomes particularly in vulnerable patients with the overlap syndrome leading to increased risk of cardiovascular diseases, acute COPD exacerbations, increased rates of hospitalizations, and nocturnal deaths. Current guidelines recommend polysomnography (PSG) as the gold standard investigation to diagnose sleep disorders and overlap syndrome. Treatment may include pulmonary rehabilitation, supplemental oxygen therapy, and non-invasive ventilation. Currently, continuous positive airway pressure (CPAP) therapy is the treatment of choice for the overlap syndrome. CPAP effects include improved respiratory mechanics; sleep quality, exercise tolerance, and prolonged survival.

Conclusion

Both COPD and OSA are common in the general population and present a significant risk of increased morbidity and mortality when they coexist in the same patient. Clinicians must carefully evaluate the clinical outcomes and the high risk of cardiovascular complications related to the overlap syndrome. Current data indicate that CPAP treatment leads to amelioration of the health-related quality of life and improve survival in patients with the overlap syndrome.

Sleep deprivation and its association with diseases- a review

Sleep deprivation, a consequence of multiple health problems or a cause of many major health risks, is a significant public health concern in this era. In the recent years, numerous reports have been added to the literature to provide explanation and to answer previously unanswered questions on this important topic but comprehensive updates and reviews in this aspect remain scarce. The present study identified 135 papers that investigated the association between sleep deprivation and health risks, including cardiovascular, respiratory, neurological, gastrointestinal, immunology, dermatology, endocrine, and reproductive health. In this review, we aimed to provide insight into the association between sleep deprivation and the development of diseases. We reviewed the latest updates available in the literature and particular attention was paid to reports that detailed all possible causal relationships involving both extrinsic and intrinsic factors that may be relevant to this topic. Various mechanisms by which sleep deprivation may affect health were presented and discussed, and this review hopes to serve as a platform for ideas generation for future research.

Enfermedad pulmonar obstructiva crónica (EPOC) Bases para el médico general

Chronic obstructive pulmonary disease (COPD) is a chronic degenerative disease. It is a frequent, preventable and treatable disease characterized by persistent respiratory symptoms and airflow limitation. The National Institute of Respiratory Diseases (INER), ranked COPD in 2016 in fourth place in the table of annual morbidity and mortality in Mexico. The prevalence of COPD is directly related to smoking; however, its development is multifactorial. For its study it is important to know of any prior exposure to risk factors and of any manifestation of the main symptoms. To make a diagnosis, a detailed clinical history, where the largest amount of data is collected from every new possible COPD patient, and a spirometry are essential. Individual pharmacological treatment is necessary due to the great variability among COPD patients. The drugs used in the treatment of COPD reduce the symptoms, the frequency and severity of exacerbations; however, there is no medication that modifies the long-term deterioration of the lung function. Therefore, a basic knowledge of this condition by the medical doctor first contacted, is essential for the suspicion of COPD in its initial stage and thus, offer the patient immediate medical intervention. The objective of the present work is to provide a basic overview of COPD to the general practitioner. Key words:Chronic obstructive pulmonary disease; biomass; tobacco; chronic obstructive bronchitis; emphysema; respiratory system

The Screening Value Of ESS, SACS, BQ, And SBQ On Obstructive Sleep Apnea In Patients With Chronic Obstructive Pulmonary Disease

Objective

To compare the performance of Epworth sleepiness scale (ESS), sleep apnea clinical score (SACS), Berlin questionnaire (BQ), and STOP-BANG questionnaire (SBQ) in screening for obstructive sleep apnea (OSA) in patients with chronic obstructive pulmonary disease (COPD).

Methods

A total of 431 patients were analyzed. All subjects completed lung function test, ESS, SACS, BQ, and SBQ survey and overnight polysomnography (PSG). According to lung function and PSG results, participants were divided into COPD with OSA group (OVS, AHI ≥5) and without OSA group (AHI <5). The value of ESS, SACS, BQ, and SBQ was compared in predicting OSA in patients with COPD by receiver-operating characteristic (ROC) curve statistics.

Results

Of the 431 subjects, there were 96 cases in COPD without OSA group, and 335 cases in OVS group including 183, 96, and 56 cases of COPD combined with mild, moderate or severe OSA. In predicting different degrees of severity of OSA in patients with COPD, the value of ESS was poor with all the values of area under the curve (AUC) < 0.7. SACS and BQ had moderate predictive value in screening for severe OSA with the value of AUC of 0.750, 0.735 respectively. However, the SBQ performed best in predicting various degrees of OSA. For screening mild OSA (AHI ≥5), the ROC statistics recommended the cut-off score of SBQ >2 was considered high risk of OSA; the sensitivity, specificity, and AUC were 92.8%, 40.6%, and 0.723 respectively, the odds ratio (OR) was 2.161. When AHI ≥15, AUC for SBQ was 0.737. In predicting severe OSA (AHI ≥30), the ROC curve showed cut-off point, sensitivity, specificity, and AUC for SBQ was >4, 66.1%, 82.1%, and 0.824 respectively; the positive and negative likelihood ratio was 3.70, 0.41 separately, the OR was 2.977.

Conclusion

SBQ performed better than ESS, SACS, and BQ in predicting OSA in patients with COPD.

Sleep in chronic respiratory disease: COPD and hypoventilation disorders

COPD and obstructive sleep apnoea (OSA) are highly prevalent and different clinical COPD phenotypes that influence the likelihood of comorbid OSA. The increased lung volumes and low body mass index (BMI) associated with the predominant emphysema phenotype protects against OSA whereas the peripheral oedema and higher BMI often associated with the predominant chronic bronchitis phenotype promote OSA. The diagnosis of OSA in COPD patients requires clinical awareness and screening questionnaires which may help identify patients for overnight study. Management of OSA-COPD overlap patients differs from COPD alone and the survival of overlap patients treated with nocturnal positive airway pressure is superior to those untreated. Sleep-related hypoventilation is common in neuromuscular disease and skeletal disorders because of the effects of normal sleep on ventilation and additional challenges imposed by the underlying disorders. Hypoventilation is first seen during rapid eye movement (REM) sleep before progressing to involve non-REM sleep and wakefulness. Clinical presentation is nonspecific and daytime respiratory function measures poorly predict nocturnal hypoventilation. Monitoring of respiration and carbon dioxide levels during sleep should be incorporated in the evaluation of high-risk patient populations and treatment with noninvasive ventilation improves outcomes.

A randomized trial to determine the impact of indacaterol/glycopyrronium on nighttime oxygenation and symptoms in patients with moderate-to-severe COPD: the DuoSleep study

PURPOSE

This study investigated the effect of dual bronchodilation with the long-acting β-receptor agonist/long-acting muscarinic antagonist combination, indacaterol/glycopyrronium (IND/GLY), on nighttime oxygenation, lung function, sleep quality, and symptoms in patients with moderate-to-severe COPD.

PATIENTS AND METHODS

This was a 4-week, double-blind, multicenter, placebo-controlled, two-period crossover study. Patients were randomized in a 1:1 ratio to receive IND/GLY 110/50 µg once daily or matching placebo. The primary objective was to evaluate the effect of treatment with IND/GLY on mean nighttime oxygenation, compared with placebo. The secondary objective was to determine the time spent <90% in blood oxygen saturation (SpO2) compared with placebo. Exploratory objectives were to assess the effect of IND/GLY, compared with placebo, on sleep quality measured by the Medical Outcomes Study (MOS) Sleep Scale and the COPD and Asthma Sleep Impact Scale (CASIS) questionnaires and on symptoms assessed by COPD Assessment Test (CAT) questionnaire.

RESULTS

In total, 38 patients were randomized (n=22, IND/GLY; n=16, placebo). The change in nighttime oxygenation (SpO2) was similar, and there was a comparable difference in time spent <90% SpO2 between IND/GLY and placebo. Increases from baseline for the difference between IND/GLY and placebo for trough FEV1, FVC, and inspiratory capacity (P<0.05) were seen, with a corresponding reduction in residual volume and functional residual capacity (P<0.05). IND/GLY treatment showed an improvement in scores for CAT (P=0.0208), CASIS, and the MOS Sleep Scale measures, Sleep Problems Index I, Sleep Problems Index II (P=0.0315), Sleep Adequacy, Sleep Disturbance Scale, Somnolence Scale, and Short of Breath Scale (P=0.0031).

CONCLUSION

In this study, IND/GLY 110/50 µg once daily improved symptoms, sleep quality, and lung function, but showed no effect on nighttime oxygenation in patients with moderate-to-severe COPD.

Association between blood pressure, inflammation and spirometry parameters in chronic obstructive pulmonary disease

BACKGROUND/AIMS

Many systems including the cardiovascular system (ischemic heart diseases, heart failure, and hypertension) may act as comorbidities that can be seen during the course of chronic obstructive pulmonary disease (COPD). Comorbidities affect the severity and prognosis of COPD negatively. Nearly 25% of patients with COPD die due to cardiovascular diseases. In this study, we aimed to evaluate the relationship between the blood pressure, inflammation, hypoxia, hypercapnia, and the severity of airway obstruction.

METHODS

We included 75 COPD patients in the study with 45 control cases. We evaluated age, sex, body mass index, smoking history, C-reactive protein levels, 24-hour ambulatory blood pressure Holter monitoring, arterial blood gas, and respiratory function tests of the patient and the control groups.

RESULTS

In COPD patients, the night time systolic, diastolic blood pressures and pulse per minute and the mean blood pressures readings were significantly elevated compared to the control group (p < 0.05). In the correlation analysis, night time systolic pressure was associated with all the parameters except forced expiratory volume in 1 second (FEV1%). Diastolic blood pressure was associated with pH and HCO3 levels. The mean night time, day time pulse pressures and 24- hour pulse per minute values were also associated with all the parameters except FEV1%.

CONCLUSION

In this study we found that parameters of systolic and diastolic blood pressures and pulse pressures were significantly elevated in COPD patients compared to the control groups. Blood pressure was associated blood gas parameters and inflammation parameters in COPD patients. This, in turn, may cause understanding of the pathophysiology of COPD and its complications.

The Overlap Syndrome

The overlap syndrome (OS) was first coined by David C. Flenley in 1985 to describe the coexistence of obstructive sleep apnea (OSA) in patients with chronic obstructive pulmonary disease (COPD). Patients with OS experience more profound nocturnal oxygen desaturation (NOD) than patients with OSA or COPD alone. This underlying hypoxia in OS increases the risk of cardiovascular disease including atrial fibrillation, right heart failure, and pulmonary hypertension, thereby increasing the mortality associated with the disease. Keeping in mind the risk of mortality, it is crucial for clinicians to clinically evaluate the patients with OSA or COPD for the occurrence of OS and provide effective treatment options for the same. This review aims to highlight the pathophysiology and the risks associated with the OS along with early detection and appropriate management protocols to reduce the mortality associated with it.

Sleep as a New Target for Improving Outcomes in Idiopathic Pulmonary Fibrosis

Idiopathic pulmonary fibrosis (IPF) is the most common type of interstitial pneumonia but remains a disease with a poor outcome. Two drugs, pirfenidone and nintedanib, have shown promising results at stalling disease progression; however, the interplay of sleep disruption or sleep disorders overall and in relation to medication effectiveness remains understudied. In the past, there was limited interest in the role of sleep in patients with IPF. Treating physicians tended to address only the daily disabling symptoms while disregarding the possible significant role of sleep alterations or coexisting sleep disorders. During the past few years, there has been more research related to sleep disturbances in patients with IPF and their possible role in sleep and overall life quality, disease progression, and outcome. In summary, sleep in patients with IPF is significantly impaired, with alterations in sleep architecture, changes in sleep breathing pattern, and decreases in oxygen saturation mainly during vulnerable rapid eye movement sleep. There also is evidence that OSA has an increased prevalence in these patients, playing an important role in the already worse sleep quality related to the disease itself. The focus of this review is not only to present current data related to sleep in patients with IPF but also to point out that therapy for sleep problems and OSA is likely to improve sleep and life quality as well as disease outcome. The main priority remains to increase awareness among treating physicians about early diagnosis of OSA in patients with IPF and to emphasize the need for intense future research, especially on the role of intermittent hypoxia superimposed on chronic hypoxia during sleep in patients with IPF.

Oxygen therapy in COPD patients with isolated nocturnal hypoxemia; comparison of quality of life and sleep between bronchitis and emphysema phenotype: A prospective observational study

BACKGROUND

COPD is a heterogeneous disease composed by two main phenotypes: bronchitis (COPDb) and emphysema (COPDe) with different clinical presentation, physiology, imaging, response to therapy and decline in lung function. The aim of this study is to evaluate whether nocturnal hypoxemic COPDb and COPDe have a different behaviour during sleep and the effect of nocturnal oxygen supplementation (nO₂LT).

MATERIALS AND METHODS

75 COPDb and 120 COPDe were enrolled. All patients performed polysomnography, Pittsburgh and Maugeri Foundation Respiratory Failure questionnaire, and pulmonary function before and after six months of nO₂LT.

RESULTS

At baseline, compared to COPDb, COPDe have decreased sleep efficiency (SE) (67.5±6% vs. 76.9±3% p<0.05) and higher arousals (A/I) (18.1±3 event/h vs. 8.7±1 event/h p<0.05). Oxygen desaturation index (ODI) was increased during REM (7.1±1 event/h vs. 2.3±0.5 event/h p<0.05). nO₂LT in COPDe improves SE (77±4% vs. 67.5±6% p<0.05) and decreases A/I (9±5 event/h vs. 18.1±3 event/h p<0.05). ODI during REM (3.5±2 event/h vs. 7.1±1 p<0.05) decreases and quality of life (QoL) improves (MFR-28 total 56±22 vs 45±20 p<0.05), due to an improvement in cognitive abilities (45±30 vs 33±31 p<0.05) and daily activities (61±29 vs 53±21 p>0.05). In COPDb nO₂LT reduces ST90 (15±6% vs. 43±8% p<0.05) less than in COPDe (15±6% vs. 8±4% p<0.05); improves A/I (10±2 event/h vs. 8.7±1 p<0.05) and there is no evidence of an improvement in QoL.

CONCLUSIONS

Six months of nO₂LT improve quality of life in COPDe, not in COPDb. We found a difference in sleep quality between COPDe and COPDb.

Sleep in Chronic Obstructive Pulmonary Disease: Evidence Gaps and Challenges

Chronic obstructive pulmonary disease (COPD) prevalence is rising to epidemic proportions due to historical smoking trends, the aging of the population, and air pollution. Although blaming the victims has been common in COPD, the majority of COPD worldwide is now thought to be nonsmoking related, that is, caused by air pollution and cookstove exposure. It is increasingly appreciated that subjective and objective sleep disturbances are common in COPD, although strong epidemiological data are lacking. People with obstructive sleep apnea (OSA) plus COPD (the so-called overlap syndrome) have a high risk of cardiovascular death, although again mechanisms are unknown and untested. This review aims to draw attention to the problem of sleep in COPD, to encourage clinicians to ask their patients about symptoms, and to stimulate further research in this area given the large burden of the disease.

Chronic obstructive pulmonary disease and obstructive sleep apnoea-the overlap syndrome

Chronic obstructive pulmonary disease (COPD) and obstructive sleep apnoea (OSA) are highly prevalent disorders and the co-existence of both disorders, termed the overlap syndrome, affects at least 1% of the adult population. Patients with the overlap syndrome typically experience more pronounced nocturnal oxygen desaturation and there is a high prevalence of pulmonary hypertension in such patients. Recent evidence suggests that the prevalence of each disorder together is higher than might be predicted by simple prevalence statistics, although the evidence is not clear-cut in this regard. Sleep itself can have several negative effects in patients with COPD. Sleep quality is diminished with reduced amounts of slow wave and rapid-eye-movement (REM) sleep, which may contribute to daytime symptoms such as fatigue and lethargy. Furthermore, normal physiological adaptations during sleep that result in mild hypoventilation in normal subjects are more pronounced in COPD, which can result in clinically important nocturnal oxygen desaturation. Management of sleep disorders in patients with COPD should address both sleep quality and disordered gas exchange. Non-invasive pressure support is beneficial in selected cases, particularly during acute exacerbations associated with respiratory failure, and is particularly helpful in patients with the overlap syndrome. There is limited evidence of benefit from pressure support in the chronic setting in COPD patients without OSA.

Improvements in sleep-related symptoms after endoscopic sinus surgery in patients with chronic rhinosinusitis

BACKGROUND

Sleep impairment is highly prevalent in patients with chronic rhinosinusitis (CRS). Although endoscopic sinus surgery (ESS) has been shown to improve overall patient-reported sleep quality, the postoperative impact on individual sleep symptoms remains unclear.

METHODS

Patients with medically-recalcitrant CRS who elected to undergo ESS were prospectively enrolled into a multi-institutional, observational cohort study. Sleep-related symptom severity and treatment outcomes were assessed using the sleep domain questions within the 22-item Sino-Nasal Outcome Test (SNOT-22).

RESULTS

A total of 334 participants met criteria and were followed postoperatively for an average of 14.5 ± 4.9 months (mean ± standard deviation [SD]). Mean SNOT-22 sleep domain scores improved from 13.7 ± 6.8 to 7.7 ± 6.6 (p < 0.001). Significant mean relative improvements were reported for "difficulty falling asleep" (45%; p < 0.001), "waking up at night" (40%; p < 0.001), "lack of a good night's sleep" (43%; p < 0.001), "waking up tired" (40%; p < 0.001), and "fatigue" (42%; p < 0.001) scores. A total of 66% of study participants reported postoperative improvement in "lack of a good night's sleep," "waking up tired," and "fatigue"; 62% reported improvement in "waking up at night"; and 58% reported improvement in "difficulty falling asleep."

CONCLUSION

Patients with CRS report significant and sustained improvements following ESS in common sleep-related symptoms as assessed by the SNOT-22 sleep domain. Despite these significant improvements, some degree of persistent postoperative sleep impairment was reported. Further study is necessary to determine what factors are associated with continued sleep dysfunction after sinus surgery.

Sleep Disturbances in the Elderly

Sleep disturbances are a common presenting symptom of older-age adults to their physicians. This article explores normal changes in sleep pattern with aging and primary sleep disorders in the elderly. Behavioral factors and primary psychiatric disorders affecting sleep in this population are reviewed. Further discussion examines sleep changes associated with 2 common forms of neurocognitive disorder: Alzheimer disease and Lewy Body Dementia. Common medical illnesses in the elderly are discussed in relation to sleep symptoms. Nonpharmacological and pharmacologic treatment strategies are summarized, with emphasis placed on risk of side effects in older adults. Future targets are considered.

Sleep Apnea Clinical Score, Berlin Questionnaire, or Epworth Sleepiness Scale: which is the best obstructive sleep apnea predictor in patients with COPD?

Introduction

The Sleep Apnea Clinical Score (SACS) and the Berlin Questionnaire (BQ) are used to predict the likelihood of obstructive sleep apnea (OSA). The Epworth Sleepiness Scale (ESS) is used to assess daytime sleepiness, a common OSA symptom. These clinical tools help prioritize individuals with the most severe illness regarding on whom polysomnography (PSG) should be performed. It is necessary to check the applicability of these tools in patients with chronic obstructive pulmonary disease (COPD). The aim of this study is to compare SACS, BQ, and ESS performance in patients with COPD.

Methods

The SACS, BQ, and ESS were applied to 91 patients with COPD. From this group, 24 underwent PSG. In this transversal study, these three tests were compared regarding their likelihood to predict OSA in patients with COPD using receiver-operating characteristic curve statistics.

Results

In this sample, 58 (63.7%) patients were men, and their mean age was 69.4±9.6 years. Fourteen patients (15.4%) had a high probability of OSA by SACS, 32 (32.5%) had a high probability by BQ, and 37 (40.7%) had excessive diurnal somnolence according to the ESS. From the 24 patients who underwent PSG, OSA diagnosis was confirmed in five (20.8%), according to the American Academy of Sleep Medicine criteria. BQ and ESS did not accurately predict OSA in this group of patients with COPD, with a receiver-operating characteristic curve area under the curves of 0.54 (95% CI: 0.329–0.745, P=0.75) and 0.69 (95% CI: 0.47–0.860, P=0.10), respectively. SACS performance was significantly better, with an area under the curve of 0.82 (95% CI: 0.606–0.943, P=0.02).

Conclusion

SACS was better than BQ and ESS in predicting OSA in this group of patients with COPD.

Systemic manifestations of chronic obstructive pulmonary disease

Chronic obstructive pulmonary disease is a complex multisystem disease with comorbidities and systemic manifestations that affect respiratory symptoms, exacerbation frequency and mortality. This article gives an overview of these systemic manifestations and their importance, and offers strategies for managing them.

Idiopathic pulmonary fibrosis and sleep disorders: no longer strangers in the night

The prevalence of obstructive sleep apnoea (OSA) is continuously increasing in patients with idiopathic pulmonary fibrosis (IPF) and, for the first time, the recent IPF guidelines recognise OSA as an important associated comorbidity that can affect patient's survival. Thus, it becomes conceivable that clinicians should refer patients with newly diagnosed IPF to sleep centres for the diagnosis and treatment of OSA as well as for addressing issues regarding the reduced compliance of patients with continuous positive airway pressure therapy. The discovery of biomarkers common to both disorders may help early diagnosis, institution of the most appropriate treatment and follow-up of patients. Better understanding of epigenetic changes may provide useful information about pathogenesis and, possibly, development of new drugs for a dismal disease like IPF.

It is now believed that IPF and sleep disorders can coexist in the same patienthttp://ow.ly/LXPSL

Impact of sleep quality on functional capacity, peripheral muscle strength and quality of life in patients with chronic obstructive pulmonary disease

PURPOSE

The purpose of this study was to assess the impact of quality of sleep on functional capacity, peripheral muscle strength and quality of life in patients with chronic obstructive pulmonary disease (COPD).

MATERIALS AND METHODS

Forty patients with COPD (61.6 ± 8.28 years) were included in this study. Subjective sleep quality (Pittsburgh sleep quality index), quality of life (Nottingham health profile), quadriceps muscle strength (QMS) and functional capacity (6-min walk test) were assessed.

RESULTS

Poor sleep quality (Pittsburgh sleep quality index total >5) was present in 57% of the patients. Patients with a poor sleep quality had significantly lower QMS and higher exercise heart rate (p < 0.05). The Pittsburgh sleep quality index total score was associated with QMS, Nottingham health profile physical mobility and sleep scores, exercise fatigue and dyspnea (p < 0.05).

CONCLUSION

Sleep quality is affected in a majority of patients with COPD. It is related with symptoms, functional capacity, peripheral muscle strength and general quality of life.

Symptoms and impact of symptoms on function and health in patients with chronic obstructive pulmonary disease and chronic heart failure in primary health care

Background

Patients with chronic obstructive pulmonary disease (COPD) and chronic heart failure (CHF) seem to have several symptoms in common that impact health. However, methodological differences make this difficult to compare.

Aim

Comparisons of symptoms, impact of symptoms on function and health between patients with COPD and CHF in primary health care (PHC).

Method

The study is cross sectional, including patients with COPD (n=437) and CHF (n=388), registered in the patient administrative systems of PHC. The patients received specific questionnaires – the Memorial Symptom Assessment Scale, the Medical Research Council dyspnea scale, and the Fatigue Impact Scale – by mail and additional questions about psychological and physical health.

Results

The mean age was 70±10 years and 78±10 years for patients with COPD and CHF respectively (P=0.001). Patients with COPD (n=273) experienced more symptoms (11±7.5) than the CHF patients (n=211) (10±7.6). The most prevalent symptoms for patients with COPD were dyspnea, cough, and lack of energy. For patients with CHF, the most prevalent symptoms were dyspnea, lack of energy, and difficulty sleeping. Experience of dyspnea, cough, dry mouth, feeling irritable, worrying, and problems with sexual interest or activity were more common in patients with COPD while the experience of swelling of arms or legs was more common among patients with CHF. When controlling for background characteristics, there were no differences regarding feeling irritable, worrying, and sexual problems. There were no differences in impact of symptoms or health.

Conclusion

Patients with COPD and CHF seem to experience similar symptoms. There were no differences in how the patients perceived their functioning according to their cardinal symptoms; dyspnea and fatigue, and health. An intervention for both groups of patients to optimize the management of symptoms and improve function is probably more relevant in PHC than focusing on separate diagnosis groups.

Respiratory mechanics and ventilatory control in overlap syndrome and obesity hypoventilation

The overlap syndrome of obstructive sleep apnoea (OSA) and chronic obstructive pulmonary disease (COPD), in addition to obesity hypoventilation syndrome, represents growing health concerns, owing to the worldwide COPD and obesity epidemics and related co-morbidities. These disorders constitute the end points of a spectrum with distinct yet interrelated mechanisms that lead to a considerable health burden. The coexistence OSA and COPD seems to occur by chance, but the combination can contribute to worsened symptoms and oxygen desaturation at night, leading to disrupted sleep architecture and decreased sleep quality. Alveolar hypoventilation, ventilation-perfusion mismatch and intermittent hypercapnic events resulting from apneas and hypopneas contribute to the final clinical picture, which is quite different from the “usual” COPD. Obesity hypoventilation has emerged as a relatively common cause of chronic hypercapnic respiratory failure. Its pathophysiology results from complex interactions, among which are respiratory mechanics, ventilatory control, sleep-disordered breathing and neurohormonal disturbances, such as leptin resistance, each of which contributes to varying degrees in individual patients to the development of obesity hypoventilation. This respiratory embarrassment takes place when compensatory mechanisms like increased drive cannot be maintained or become overwhelmed.

Although a unifying concept for the pathogenesis of both disorders is lacking, it seems that these patients are in a vicious cycle. This review outlines the major pathophysiological mechanisms believed to contribute to the development of these specific clinical entities. Knowledge of shared mechanisms in the overlap syndrome and obesity hypoventilation may help to identify these patients and guide therapy.

Insomnia symptoms, objectively measured sleep, and disease severity in chronic obstructive pulmonary disease outpatients

BACKGROUND

Sleep disturbances are known to have a negative impact on a range of clinical outcomes in chronic obstructive pulmonary disease (COPD). We examined the associations of insomnia symptoms and objectively measured sleep parameters to a composite score for body mass index, airflow obstruction, dyspnea, and exercise capacity (BODE) index (a multidimensional index of COPD severity), arterial blood gases, nocturnal respiratory disturbances, periodic limb movements (PLM), psychologic distress, pain, age, and sex.

METHODS

The sample comprised 73 COPD outpatients (mean age, 63.6years; standard deviation {SD}, 7.5; range 47-85years; 41.1% women). Insomnia symptoms were measured with the Bergen Insomnia Scale (BIS) and sleep efficiency (SE), slow-wave sleep (SWS), and total sleep time (TST) were assessed with clinical polysomnography (PSG).

RESULTS

BODE index was positively associated with composite BIS score (P=.040). Patients with more severe COPD presented more complaints of nonrestorative sleep compared to patients with less severe COPD (P=.010). In multivariate analysis, the composite BIS score was independently associated with PLM (P<.001), nocturnal respiratory disturbances (P=.001), pain (P=.031), and psychologic distress (P=.044) but not with the BODE index. Objectively measured sleep variables were not associated with any of the health-related variables.

CONCLUSION

Insomnia symptoms in COPD patients result from a wide range of health-related factors. More severe COPD may be associated with a subjective experience of nonrestorative sleep but not with objectively measured sleep variables.

Exercise and COPD: therapeutic responses, disease-related outcomes, and activity-promotion strategies

Chronic obstructive pulmonary disease (COPD) reduces patients' exercise capacities and their abilities to perform daily physical activities, thereby increasing morbidity and mortality rates. The cycle of dyspnea, deconditioning, and declining physical activity not only accelerates the progression of COPD but also increases the risk for developing or aggravating metabolic and cardiovascular diseases. Cardiovascular and metabolic comorbidities also limit physical function, and their disabling effects in combination with COPD may be greater than the effects of each disease alone. The impact of COPD and its treatment on the ability to exercise, and the degree of physical activity in daily life, can be measured by field-based tests (eg, the 6-minute walk test or incremental and endurance shuttle-walk test), laboratory-based tests (eg, incremental or constant work-rate treadmill and cycle-ergometer tests), and physical activity assessments (eg, questionnaires and accelerometers). Walking tests increase oxygen consumption and desaturation in patients with COPD more than cycling tests with similar work-rate profiles and may more closely resemble patients' normal activities. Despite the questionable relevance of exercise testing to patients' daily functionality, exercise parameters remain important predictors of survival in patients with COPD. Treatment of COPD (pharmacotherapy, pulmonary rehabilitation, or both) can increase exercise capacity and physical activity in daily life, which potentially slows the decline of lung function, reduces the frequencies of exacerbations and hospitalizations, decreases mortality, slows the progression of comorbidities, improves health-related quality of life, and increases the activity reserve for routine function. This article examines the interactions of reduced physical activity and decreased exercise capacity with the progression of COPD, comorbidities, and mortality. The article also describes the available exercise tests for patients with COPD and reviews the evidence indicating that treating COPD improves exercise capacity. Notably, it appears that even mild COPD reduces exercise capacity and daily physical activity, indicating the need for early intervention.