Sleep disordered breathing and chronic obstructive pulmonary disease: a narrative review on classification, pathophysiology and clinical outcomes

Sleep Hypoventilation is Common in Diurnal Normocapnic COPD Patients with Severe or Very Severe Obstruction and is Not Associated with Body Mass Index

Sleep hypoventilation (SH) is common in COPD patients with diurnal hypercapnia, however there are little data on the presence of SH in COPD patients with diurnal normocapnia. In this study the prevalence of SH in stable normocapnic COPD patients with severe or very severe obstruction (GOLD stages III and IV) was evaluated across body mass index (BMI) classes and associations between SH and body composition measures were explored. A total of 56 diurnal normocapnic COPD patients, of whom 17 normal-weight (COPD_NW), 18 overweight (COPD_OW) and 21 obese (COPD_OB), underwent polysomnography to objectify SH and bioelectrical impedance analysis to assess body composition. The overall prevalence of SH was 66.1% and was not different across BMI classes. Logistic regression models indicated that SH was not associated with waist-to-hip ratio, body fat percentage and fat-free mass index. Our data indicate that SH is common in diurnal normocapnic COPD patients with severe or very severe obstruction and is not associated with BMI or body composition.

Monitoring and Management of Respiratory Function in Pompe Disease: Current Perspectives

Pompe disease (PD) is a neuromuscular disorder caused by a deficiency of acid alpha-glucosidase (GAA) - a lysosomal enzyme responsible for hydrolyzing glycogen. GAA deficiency leads to accumulation of glycogen in lysosomes, causing cellular disruption. The severity of PD is directly related to the extent of GAA deficiency - if no or minimal GAA is produced, symptoms are severe and manifest in infancy, known as infantile onset PD (IOPD). If left untreated, infants with IOPD experience muscle hypotonia and cardio-respiratory failure leading to significant morbidity and mortality in the first year of life. In contrast, late-onset PD (LOPD) patients have more GAA activity and present later in life, but also have significant respiratory function decline. Despite FDA-approved enzyme replacement therapy, respiratory insufficiency remains a major cause of morbidity and mortality, emphasizing the importance of early detection and management of respiratory complications. These complications include impaired cough and airway clearance, respiratory muscle weakness, sleep-related breathing issues, and pulmonary infections. This review aims to provide an overview of the respiratory pathology, monitoring, and management of PD patients. In addition, we discuss the impact of novel approaches and therapies on respiratory function in PD.

Biomarkers of the L-Arginine/Dimethylarginine/Nitric Oxide Pathway in People with Chronic Airflow Obstruction and Obstructive Sleep Apnoea

BACKGROUND

Chronic obstructive pulmonary disease (COPD) and obstructive sleep apnoea (OSA) are common chronic diseases that are associated with chronic and intermittent hypoxemia, respectively. Patients affected by the overlap of COPD and OSA have a particularly unfavourable prognosis. The L-arginine/nitric oxide (NO) pathway plays an important role in regulating pulmonary vascular function. Asymmetric (ADMA) and symmetric dimethylarginine (SDMA) interfere with NO production.

METHODS

We analysed the serum concentrations of ADMA, SDMA, L-arginine, L-citrulline, and L-ornithine in a large sample of the Icelandic general population together with chronic airflow obstruction (CAO), a key physiological marker of COPD that was assessed by post-bronchodilator spirometry (FEV1/FVC < LLN). OSA risk was determined by the multivariable apnoea prediction (MAP) index.

RESULTS

713 individuals were analysed, of whom 78 (10.9%) showed CAO and 215 (30%) had MAP > 0.5. SDMA was significantly higher in individuals with CAO (0.518 [0.461-0.616] vs. 0.494 [0.441-0.565] µmol/L; p = 0.005), but ADMA was not. However, ADMA was significantly associated with decreasing FEV1 percent predicted among those with CAO (p = 0.002). ADMA was 0.50 (0.44-0.56) µmol/L in MAP ≤ 0.5 versus 0.52 (0.46-0.58) µmol/L in MAP > 0.5 (p = 0.008). SDMA was 0.49 (0.44-0.56) µmol/L versus 0.51 (0.46-0.60) µmol/L, respectively (p = 0.004). The highest values for ADMA and SDMA were observed in individuals with overlap of CAO and MAP > 0.5, which was accompanied by lower L-citrulline levels.

CONCLUSIONS

The plasma concentrations of ADMA and SDMA are elevated in COPD patients with concomitant intermittent hypoxaemia. This may account for impaired pulmonary NO production, enhanced pulmonary vasoconstriction, and disease progression.

Quality of life in patients with chronic respiratory failure on home mechanical ventilation

Home mechanical ventilation (HMV) is a treatment for chronic respiratory failure that has shown clinical and cost effectiveness in patients with underlying COPD, obesity-related respiratory failure and neuromuscular disease (NMD). By treating chronic respiratory failure with adequate adherence to HMV, improvement in patient-reported outcomes including health-related quality of life (HRQoL) have been evaluated using general and disease-specific quantitative, semi-qualitative and qualitative methods. However, the treatment response in terms of trajectory of change in HRQoL is not uniform across the restrictive and obstructive disease groups. In this review, the effect of HMV on HRQoL across the domains of symptom perception, physical wellbeing, mental wellbeing, anxiety, depression, self-efficacy and sleep quality in stable and post-acute COPD, rapidly progressive NMD (such as amyotrophic lateral sclerosis), inherited NMD (including Duchenne muscular dystrophy) and obesity-related respiratory failure will be discussed.

Monocyte to eosinophil ratio as a diagnostic biomarker for overlap syndrome and predictor of disease exacerbation

Objectives: Chronic Obstructive Pulmonary Disease (COPD) is one of the most common pulmonary diseases. The concomitant association of Obstructive Sleep Apnea (OSA) and COPD is known as the Overlap Syndrome (OS). This study aimed to identify markers for predicting OS, among routine laboratory tests, including differential blood counts.Methods: One hundred twenty-five patients with exacerbated COPD were enrolled in the study and screened for OSA using the Epworth Sleepiness Scale (ESS). Those with a positive ESS score underwent polysomnography (PSG) for confirmation. All patients were followed for 90 days to monitor for subsequent exacerbations.Results: Out of the 125 patients with exacerbated COPD, 25 were confirmed to have OSA. Those with OS had a significantly higher body mass index (BMI) (p < 0.001). The monocyte to eosinophil ratio (MER) was significantly higher in the OS group, while the neutrophil to monocyte (NMR) ratio and platelets to monocyte (PMR) ratio were significantly lower. Younger age, male sex, and higher body mass index (BMI) were all associated with OS. During the 90-day follow-up period after hospital discharge, 60% of patients with OS were re-admitted due to acute exacerbations. The hazard ratio for a second exacerbation increased by two-fold for every one-unit increase MER. The MER demonstrated excellent utility in predicting a second exacerbation, with an area under the curve (AUC) of 83% and a p-value of .005.Conclusion: The monocyte to eosinophil ratio (MER) was independent predictors of OS among exacerbated COPD patients and had a very good prognostic utility for predicting the next exacerbation episodes. Long term follow up is recommended to evaluate the severity of exacerbations and the effect of complications of OS on the morbidity and mortality of these patients.

Sleep medicine: Practice, challenges and new frontiers

Sleep medicine is an ambitious cross-disciplinary challenge, requiring the mutual integration between complementary specialists in order to build a solid framework. Although knowledge in the sleep field is growing impressively thanks to technical and brain imaging support and through detailed clinic-epidemiologic observations, several topics are still dominated by outdated paradigms. In this review we explore the main novelties and gaps in the field of sleep medicine, assess the commonest sleep disturbances, provide advices for routine clinical practice and offer alternative insights and perspectives on the future of sleep research.

The Impact of Non-Invasive Ventilation on Sleep Quality in COPD Patients

Background: Non-invasive ventilation (NIV) has been shown to be the most appropriate therapy for COPD patients with chronic respiratory failure. While physiological parameters and long-term outcome frequently serve as primary outcomes, very few studies have primarily addressed the impact of NIV initiation on sleep quality in COPD. Methods: This single-center prospective cohort study comprised NIV-naïve patients with COPD. All patients underwent polysomnographic evaluation both at baseline and at 3 months follow-up, accompanied by the assessment of health-related quality of life (HRQL) using the Severe Respiratory Insufficiency Questionnaire (SRI) and the Epworth Sleepiness Scale (ESS). A subgroup evaluation was performed to address the impact of comorbid obstructive sleep apnea syndrome (OSAS). Results: Forty-six patients were enrolled and twenty-five patients completed the follow-up period (66.7 ± 7.4 years). NIV resulted in an increase in slow-wave sleep (+2% (−3.5/7.5), p = 0.465) and rapid eye movement sleep (+2.2% (−1.0/5.4), p = 0.174), although no statistical significance could be detected. ESS (−1.7(−3.6/0.1), p = 0.066) also showed a positive trend. Significant improvements in the Respiratory Disturbance Index (RDI) (−12.6(−23.7/−1.5), p = 0.027), lung function parameters, transcutaneous PCO₂ and the SRI summary scale (4.5(0.9/8), p = 0.016) were observed. Conclusion: NIV therapy does not decrease sleep quality and is even capable of improving HRQL, transcutaneous PaCO₂, daytime sleepiness and RDI, and the latter especially holds true for patients with comorbid OSAS.

Non-pharmacological Management in Palliative Care for Patients With Advanced COPD

Chronic obstructive pulmonary disease (COPD) is a disabling condition associated with progressive airflow limitation and lung tissue damage; its main symptoms are breathlessness, fatigue, cough, and sputum production. In the advanced stage of the disease, these symptoms may severely impact on a person's physical and psychological functioning, with some also developing chronic respiratory failure, associated with blood gas abnormalities. Non-pharmacological interventions can improve quality of life and functioning in the management of people living with advanced COPD. This article will provide an overview of common non-pharmacological methods used in the symptomatic management of severe COPD, including: breathlessness and fatigue management strategies, anxiety management, pulmonary rehabilitation (PR) and physical activity (PA), neuromuscular electrical stimulation (NMES), airway clearance techniques (ACTs), nutrition and non-invasive ventilation (NIV). The importance of a holistic and multi-disciplinary approach to people living with COPD will be discussed.

A New Berlin Questionnaire Simplified by Machine Learning Techniques in a Population of Italian Healthcare Workers to Highlight the Suspicion of Obstructive Sleep Apnea

Obstructive sleep apnea (OSA) syndrome is a condition characterized by the presence of repeated complete or partial collapse of the upper airways during sleep associated with episodes of intermittent hypoxia, leading to fragmentation of sleep, sympathetic nervous system activation, and oxidative stress. To date, one of the major aims of research is to find out a simplified non-invasive screening system for this still underdiagnosed disease. The Berlin questionnaire (BQ) is the most widely used questionnaire for OSA and is a beneficial screening tool devised to select subjects with a high likelihood of having OSA. We administered the original ten-question Berlin questionnaire, enriched with a set of questions purposely prepared by our team and completing the socio-demographic, clinical, and anamnestic picture, to a sample of Italian professional nurses in order to investigate the possible impact of OSA disease on healthcare systems. According to the Berlin questionnaire, respondents were categorized as high-risk and low-risk of having OSA. For both risk groups, baseline characteristics, work information, clinical factors, and symptoms were assessed. Anthropometric data, work information, health status, and symptoms were significantly different between OSA high-risk and low-risk groups. Through supervised feature selection and Machine Learning, we also reduced the original BQ to a very limited set of items which seem capable of reproducing the outcome of the full BQ: this reduced group of questions may be useful to determine the risk of sleep apnea in screening cases where questionnaire compilation time must be kept as short as possible.

Obstructive Sleep Apnea is Associated with an Increased Prevalence of Polycythemia in Patients with Chronic Obstructive Pulmonary Disease

Purpose

Chronic obstructive pulmonary disease (COPD) and obstructive sleep apnea (OSA) are associated with polycythemia. However, there still remain unanswered questions about the relationship between overlap syndrome (OVS), where OSA and COPD coexist, and polycythemia. Here, we aimed to establish the prevalence of polycythemia in OVS patients and to explore the impact of OSA on polycythemia.

Patients and Methods

Patients with COPD underwent overnight polysomnography (PSG), pulmonary function tests, echocardiography, and complete blood counts. All patients were ethnic Han Chinese and free of prolonged oral corticosteroid use, hematological system disease, severe systemic disease, and other sleep-disordered breathing. OVS was defined as COPD patients with an apnea–hypopnea index ≥15 events/h, and polycythemia was defined as an Hb >165 g/L in men and >160 g/L in women.

Results

Eight-hundred and eighty-six patients with COPD were included in the analysis. The prevalence of polycythemia was significantly higher in OVS patients than COPD-alone patients (6.4% vs 2.9%, p < 0.05). The prevalence of polycythemia increased with OSA severity (χ² = 7.885, p = 0.007), but not in GOLD grade 3–4 COPD patients (χ² = 0.190, p = 0.663). After adjusting for confounders, percentage of total sleep time with SaO₂ <90% (TS₉₀) remained independently associated with an increased odds of polycythemia (OR 1.030, 95% CI 1.015–1.046) and, with an increase in TS₉₀, the hemoglobin increased, especially in GOLD grade 1–2 patients (p < 0.05).

Conclusion

Patients with OVS have a higher prevalence of polycythemia than those with COPD alone, and TS₉₀ is an independent factor for polycythemia, especially in GOLD1-2 COPD patients.

Sleep Apnea & Chronic Obstructive Pulmonary Disease: Overlap Syndrome Dynamics in Patients from an Epidemiological Study

Obstructive sleep apnea (OSA) is a sleep disorder in which repetitive upper airway obstructive events occur during sleep. These events can induce hypoxia, which is a risk factor for multiple cardiovascular and cerebrovascular diseases. Chronic obstructive pulmonary disease (COPD) is a disorder which induces a persistent inflammation of the lungs. This condition produces hypoventilation, affecting the blood oxygenation, and leads to an increased risk of developing lung cancer and heart disease. In this study, we evaluated how COPD affects the severity and characteristics of OSA in a multivariate demographic database including polysomnographic signals. Results showed SpO2 subtle variations, such as more non-recovered desaturations and increased time below a 90% SpO2 level, which, in the long term, could worsen the risk to suffer cardiovascular and cerebrovascular diseases.Clinical Relevance- COPD increases the OSA risk due to hypoventilation and altered SpO2 behavior.

Characteristics of the nocturnal desaturation waveform pattern of SpO2 in COPD patients: an observational study

BACKGROUND

Nocturnal desaturation is common in patients with chronic obstructive pulmonary disease (COPD) and impacts disease exacerbation and prognosis. In our previous study, we developed a diagnostic algorithm to classify nocturnal desaturation from SpO₂ waveform patterns based on data from patients receiving home oxygen therapy. In this study, we aimed to investigate nocturnal desaturation in patients with COPD based on SpO₂ waveform patterns and the associations between the waveforms and clinical data.

METHODS

We investigated patients diagnosed with COPD and measured SpO₂ and nasal airflow with a type 4 portable long-term recordable pulse oximeter. Then, we classified the SpO₂ waveforms with the algorithm and compared the clinical data.

RESULTS

One hundred fifty-three patients (136 male and 17 female) were analysed. One hundred twenty-eight of the 153 (83.7%) patients had nocturnal desaturation, with an intermittent pattern (70.6%), sustained pattern (13.1%) and periodic pattern (68.0%). Intriguingly, desaturation with an intermittent pattern was associated with the apnoea-hypopnea index obtained with the portable monitor, and desaturation with a sustained pattern was associated with the cumulative percentage of time at a SpO₂ below 90%.

CONCLUSIONS

We found that nocturnal desaturation was frequently observed in patients with COPD and could be classified into 3 types of waveform patterns.

Paradoxical bronchospasm in U.S. military veterans with COPD or asthma at a tertiary VA medical center in Chicago, Illinois

Inhaled short-acting β₂-adrenergic agonists can rarely elicit paradoxical bronchospasm (PB), which may be fatal. The purpose to this study was to determine whether post-bronchodilator PB is reported in spirometry test results of veterans with Chronic Obstructive Pulmonary Disease (COPD) or asthma followed at the Jesse Brown Veterans Affairs (VA) Medical Center in Chicago between 2017-2020. Eighteen of 1,150 test reports reviewed were identified with post-bronchodilator PB (1.5%).12 out of the 18 identified patients with PB had COPD, 4 hadasthma and 2 had asthma/COPD. No report alluded to post-bronchodilator PB. Among the identified PB patients, there were 17 males and one female, 14 African Americans, 3 Caucasian and one Latinx, aged 67±8 years (mean±SD) with BMI 28±5 kg/m². Thirteen were ex-tobacco smokers, 4 current smokers and one never smoked. Most recent chest CT revealed emphysema in 8 veterans with COPD and bronchial wall thickening in 3. Chest radiographs of 4 veterans with asthma were unremarkable. All veterans were treated with inhaled β₂-adrenergic agonists. Five were treated with cardio selective beta₁ blockers and 10 for gastroesophageal reflux disease. Eleven veterans were diagnosed with obstructive sleep apnea. In 12 veterans, inhaled albuterol (4 actuations)-induced decrease in FEV₁ was 22±8% and 367±167 mL from baseline. In 6 veterans, only FVC decreased significantly from baseline (14±3% and 448±179 mL). No veteran reported respiratory symptoms during or after spirometry testing. Two veterans died during follow-up. Based on spirometry test reports, inhaled β₂-adrenergic agonists were discontinued in 2 veterans with COPD and asthma. We propose that post-bronchodilator PB observed during spirometry testing of veterans should be recognized and reported, and its possible clinical implications addressed accordingly.

Does testing for sleep-disordered breathing pre-discharge versus post-discharge result in different treatment outcomes?

STUDY OBJECTIVES

Treatment of sleep-disordered breathing (SDB) may improve health related outcomes post-discharge. However timely definitive sleep testing and provision of ongoing therapy has been a challenge. Little is known about how the time of testing-during hospitalization vs. after discharge-affects important outcomes such as treatment adherence.

METHODS

We conducted a 10-year retrospective study of hospitalized adults who received an inpatient sleep medicine consultation for SDB and subsequent sleep testing. We divided them into inpatient and outpatient sleep testing cohorts and studied their clinical characteristics, follow-up and PAP adherence, and hospital readmission.

RESULTS

Of 485 patients, 226 (47%) underwent inpatient sleep testing and 259 (53%) had outpatient sleep testing. The median age was 68 years old (IQR=57-78), and 29.6% were females. The inpatient cohort had a higher Charlson Comorbidity Index (CCI) (4 [3-6] vs 3[2-5], p=<0.0004). A higher CCI (HR=1.14, 95%CI:1.03-1.25, p=0.001), BMI (HR=1.03, 95%CI:1.0-1.05, p=0.008) and stroke (HR=2.22, 95%CI:1.0-4.9, p=0.049) were associated with inpatient sleep testing. The inpatient cohort kept fewer follow-up appointments (39.90% vs 50.62%, p=0.03) however PAP adherence was high among those keeping follow-up appointments (88.9% [inpatient] vs 85.71% [outpatient], p=0.55). The inpatient group had an increased risk for death (HR: 1.82 95%CI 1.28-2.59, p=<0.001) but readmission rates did not differ.

CONCLUSIONS

Medically complex patient were more likely to receive inpatient sleep testing but less likely to keep follow-up, which could impact adherence and effectiveness of therapy. Novel therapeutic interventions are needed to increase sleep medicine follow-up post-discharge which may result in improvement in health outcomes in hospitalized patients with SDB.