Interstitial lung disease and obstructive sleep apnea

Pulmonary vascular disease in chronic lung diseases: cause or comorbidity?

PURPOSE OF REVIEW

To provide timely and relevant insights into the complex relationship between pulmonary vascular disease (PVD) and chronic lung disease (CLD), focusing on the causative and consequential dynamics between these conditions.

RECENT FINDINGS

There are shared pathogenic mechanisms between pulmonary arterial hypertension (PAH) and group 3 pulmonary hypertension, including altered expression of mediators and growth factors implicated in both conditions. Factors such as hypoxia, hypoxemia, and hypercapnia also contribute to pulmonary vascular remodelling and endothelial dysfunction. However, the role of hypoxia as the sole driver of pulmonary hypertension in CLD is being reconsidered, particularly in chronic obstructive pulmonary disease (COPD), with evidence suggesting a potential role for cigarette smoke products in initiating pulmonary vascular impairment. On the other hand, interstitial lung disease (ILD) encompasses a group of heterogeneous lung disorders characterized by inflammation and fibrosis of the interstitium, leading to impaired gas exchange and progressive respiratory decline, which could also play a role as a cause of pulmonary hypertension.

SUMMARY

Understanding the intricate interplay between the pulmonary vascular compartment and the parenchymal and airway compartments in respiratory disease is crucial for developing effective diagnostic and therapeutic strategies for patients with PVD and CLD, with implications for both clinical practice and research.

Assessing the impact of continuous positive airway pressure therapy on clinical outcomes in interstitial lung disease patients with coexisting obstructive sleep apnea: a systematic review

PURPOSE

Interstitial lung disease (ILD) often coexists with obstructive sleep apnea (OSA), contributing to increased morbidity and mortality. However, the effectiveness of continuous positive airway pressure (CPAP) therapy in this population remains unclear. We conducted a systematic review to evaluate CPAP therapy's impact on clinical outcomes in patients with ILD and comorbid OSA.

METHODS

Following PRISMA guidelines, we systematically searched multiple databases for studies assessing CPAP therapy's effects on ILD exacerbation, hospitalization, quality of life, and mortality in ILD-OSA patients. Studies were selected based on predefined inclusion criteria, and their quality was assessed using the Newcastle-Ottawa quality scale.

RESULTS

Among 485 articles screened, 82 underwent full review, with four observational studies meeting inclusion criteria. CPAP therapy demonstrated potential benefits in improving quality of life and reducing ILD exacerbations in ILD-OSA patients. However, its impact on mortality was inconclusive due to variability in study definitions and methodology.

CONCLUSION

CPAP therapy may improve outcomes in ILD-OSA patients, particularly in terms of quality of life and ILD exacerbations. Nonetheless, further research with standardized definitions and rigorous methodology is needed to confirm its efficacy, particularly regarding mortality outcome.

Risk of sleep disorders in patients with pneumoconiosis: a retrospective cohort study

BACKGROUND

Pneumoconiosis is associated with pulmonary and cardiovascular diseases; however, the link between pneumoconiosis and sleep disorders is not well understood. This study aimed to investigate the connection between pneumoconiosis and subsequent risk of sleep disorders.

METHODS

This population-based retrospective cohort study used data from the National Health Insurance database in Taiwan. The pneumoconiosis cohort consisted of 13,329 patients newly diagnosed between 2000 and 2015. The comparison group included 53,316 age-, sex-, and diagnosis date-matched individuals without pneumoconiosis. The development of sleep disorders was monitored until the end of 2018. Cox proportional hazard regression models were used for risk assessment.

RESULTS

The incidence of sleep disorders was 1.31 times higher in the pneumoconiosis cohort than in the comparison cohort (22.8 vs. 16.2 per 1000 person-years). After controlling for age, sex, comorbidity, and medication, the adjusted hazard ratio (aHR) was 1.24 (95% confidence interval [CI] = 1.17-1.32). Stratified analyses by age group, sex, and comorbidity status showed significant associations between pneumoconiosis and sleep disorders (aHRs, 1.19-1.64). In addition, patients with pneumoconiosis had a significantly increased risk of developing sleep apnea (aHR = 1.71, 95% CI = 1.31-2.22).

CONCLUSION

This study demonstrates that patients with pneumoconiosis are at a higher risk of developing sleep disorders and sleep apnea. Healthcare professionals should pay close attention to sleep quality and disturbances in patients with pneumoconiosis.

Research trends and hotspots regarding treatment of obstructive sleep apnea

Background

Obstructive sleep apnea (OSA) is a type of sleep-disordered breathing disease, with high prevalence and multiple complications. It seriously affects patients' quality of life and even threatens their lives. Early and effective treatment can significantly improve patients' health conditions.

Objective

In this study, the main treatment methods, research hotspots and trends of OSA were summarized through bibliometric and visualization analysis.

Methods

From the Web of Science Core Collection database, articles on the treatment of OSA from 1999 to 2022 were obtained. CiteSpace and VOSviewer were comprehensively used to visualization of journals, co-authorship of countries, institutions and authors, co-citation of references, keywords cluster and burst.

Results

A total of 2,874 publications were obtained, of which 2,584 were concerned adults and 290 about children. In adults' research, Sleep and Breathing is the most published journal (280, 10.84%), the largest number of publications come from the United States (636,24.61%) and the University of Sydney (88, 3.41%), and Pepin JL is the most published author (48, 18.58%). In children's studies, International Journal of Pediatric Otorhinolaryngology is the most published journal (41, 14.14%), the maximum number of publications were also from the United States (123, 42.41%), with the University of Pennsylvania (20, 6.90%) and Marcus CL (15, 5.17%) being the most published institutions and authors. High-frequency keywords for adults' researches include positive airway pressure, oral appliance, surgery and positional therapy. On these basis, children's studies also focus on myofunctional therapy, rapid maxillary expansion and hypoglossal nerve Stimulation.

Conclusion

Over the past two decades, research in the field of OSA therapeutics has experienced significant growth in depth and breadth. The author cooperation network has already established a solid foundation, while there is potential for further strengthening the cooperation network between countries and institutions. Currently, positive airway pressure and surgery are the primary treatments for OSA in adults and children. Future research will focus on multidisciplinary combination targeted therapy, which presents a key area of interest and challenge.

Beyond the Lungs: O 2 Supplementation Improves Cerebral Oxygenation and Fatigue during Exercise in Interstitial Lung Disease

PURPOSE

Cerebral hypoxia may exacerbate the perception of fatigue. We previously demonstrated that exercise-related hypoxemia, a hallmark of fibrotic interstitial lung disease ( f -ILD), dose dependently impairs cerebral oxygenation in these patients. It is unknown whether normalizing cerebral oxygenation with O 2 supplementation would be associated with positive changes in a relevant patient-centered outcome during exercise in f -ILD, such as improved perceived fatigue.

METHODS

Fourteen patients (12 males, 72 ± 8 yr, 8 with idiopathic pulmonary fibrosis, lung diffusing capacity for carbon monoxide = 44% ± 13% predicted) performed a constant-load (60% peak work rate) cycle test to symptom limitation (Tlim) breathing medical air. Fourteen controls cycled up to Tlim of an age- and sex-matched patient. Patients repeated the test on supplemental O 2 (fraction of inspired O 2 = 0.41 ± 0.08) for the same duration. Near-infrared spectroscopy and the rating-of-fatigue (ROF) scale assessed prefrontal cortex oxygenation and perceived fatigue, respectively.

RESULTS

Patients showed severe exertional hypoxemia (Tlim O 2 saturation by pulse oximetry = 80% ± 8%); they had poorer cerebral oxygenation (e.g., oxy-deoxyhemoglobin difference [HbDiff] = -3.5 ± 4.7 [range = -17.6 to +1.9] vs +1.9 ± 1.7 μmol from rest) and greater fatigue (ROF = 6.2 ± 2.0 vs 2.6 ± 2.3) versus controls under air ( P < 0.001). Reversal of exertional hypoxemia with supplemental O 2 led to improved HbDiff (+1.7 ± 2.4 μmol from rest; no longer differing from controls) and lower ROF scores (3.7 ± 1.2, P < 0.001 vs air) in patients. There was a significant correlation between O 2 -induced changes in HbDiff and ROF scores throughout exercise in f -ILD ( rrepeated-measures correlation = -0.51, P < 0.001).

CONCLUSIONS

Supplemental O 2 improved cerebral oxygenation during exercise in f -ILD, which was moderately associated with lower ratings of perceived fatigue. Reversing cerebral hypoxia with O 2 supplementation may thus have positive effects on patients' disablement beyond those expected from lower ventilation and dyspnea in this patient population.

Treatable traits: a comprehensive precision medicine approach in interstitial lung disease

Interstitial lung disease (ILD) is a diverse group of inflammatory and fibrotic lung conditions causing significant morbidity and mortality. A multitude of factors beyond the lungs influence symptoms, health-related quality of life, disease progression and survival in patients with ILD. Despite an increasing emphasis on multidisciplinary management in ILD, the absence of a framework for assessment and delivery of comprehensive patient care poses challenges in clinical practice. The treatable traits approach is a precision medicine care model that operates on the premise of individualised multidimensional assessment for distinct traits that can be targeted by specific interventions. The potential utility of this approach has been described in airway diseases, but has not been adequately considered in ILD. Given the similar disease heterogeneity and complexity between ILD and airway diseases, we explore the concept and potential application of the treatable traits approach in ILD. A framework of aetiological, pulmonary, extrapulmonary and behavioural and lifestyle treatable traits relevant to clinical care and outcomes for patients with ILD is proposed. We further describe key research directions to evaluate the application of the treatable traits approach towards advancing patient care and health outcomes in ILD.

Association between smoking and obstructive sleep apnea based on the STOP-Bang index

Smoking is a risk factor for respiratory diseases, and it worsens sleep quality due to nicotine stimulation and sudden nicotine withdrawal during sleep. This can increase the severity of OSA through alterations upper airway inflammation and neuromuscular function, arousal mechanisms, and sleep architecture. Therefore, it may lead to sleep-disrupted breathing, particularly obstructive sleep apnea (OSA). Herein, this study aims to research the association between smoking and OSA through the STOP-Bang index. In this study, total sample of 3442 participants (1465 men and 1977 women) were analyzed. We used data from the Korea National Health and Nutrition Examination Survey in 2020 by classifying adults into current, ex-, and non-smokers. A multiple logistic regression analysis was used to investigate the association between smoking and OSA. Furthermore, multinomial regression analysis was used to investigate the effect of smoking cessation. For males, compared to the non-smokers, the odds ratios (OR) for the OSA were significantly higher in the ex-smokers (OR: 1.53, 95% confidence interval(CI) 1.01-2.32) and current smokers (OR: 1.79, 95% CI 1.10-2.89). In females, higher ORs were observed for OSA risk, similar to the non-smokers, smoking cessation, and pack-years. Among men, OSA was significantly associated with a moderate risk for ex-smokers (OR: 1.61, 95% CI 1.05-2.48) and a severe risk for current smokers (OR: 1.88, 95% CI 1.07-3.29). This study observed that smoking might contribute to OSA risk among adults. Smoking cessation can help to manage sleep quality properly.

Intermittent hypoxia exacerbated depressive and anxiety-like behaviors in the bleomycin-induced pulmonary fibrosis mice

Depression and anxiety are prevalent in patients with idiopathic pulmonary fibrosis (IPF). Recent researchers reveal that intermittent hypoxia (IH) increases the severity of bleomycin (BLM)-induced lung injury. However, experimental studies dealing with anxiety- and depression-like behavior in animal models of BLM-induced pulmonary fibrosis in a combination of IH are lacking, hence, this study aimed to investigate that. In this study, 80 C57BL/6J male mice were intratracheally injected with BLM or normal saline at day0 and then exposed to IH (alternating cycles of FiO₂ 21% for 60s and FiO₂ 10% for 30s, 40 cycles/hour, 8hours/day) or intermittent air (IA) for 21 days. Behavioral tests, including open field test (OFT), sucrose preference test (SPT) and tail suspension test (TST), were detected from day22 to day26. This study found that pulmonary fibrosis developed and lung inflammation were activated in BLM-induced mice, which were potentiated by IH. Significant less time in center and less frequency of entries in the centre arena in OFT were observed in BLM treated mice, and IH exposure further decreased that. Marked decreased percent of sucrose preference in SPT, and significant increased immobility time of the TST were detected in BLM treated mice and IH widen the gaps. The expression of ionized calcium-binding adaptor molecule (Iba1) was activated in the hippocampus of BLM instillation mice and IH enlarged it. Moreover, a positive correlation between hippocampal microglia activation and inflammatory factors was observed. Our results demonstrated that IH exacerbated depressive and anxiety-like behaviors in the BLM-induced pulmonary fibrosis mice. The changes in pulmonary inflammation-hippocampal microglia activation may be a potential mechanism in this phenomenon, which can be researched in future.

Diagnosing sleep disordered breathing in patients with chronic pulmonary disease: which test for which patient?

Overnight polysomnography should be the first-line diagnostic test in patients with severe respiratory disease. However, if access to polysomnography is limited, overnight polygraphy can be used as an alternative first-line diagnostic. https://bit.ly/3KlmFED.

Portable evaluation of obstructive sleep apnea in adults: A systematic review

Obstructive sleep apnea (OSA) is a significant healthcare burden affecting approximately one billion people worldwide. The prevalence of OSA is rising with the ongoing obesity epidemic, a key risk factor for its development. While in-laboratory polysomnography (PSG) is the gold standard for diagnosing OSA, it has significant drawbacks that prevent widespread use. Portable devices with different levels of monitoring are available to allow remote assessment for OSA. To better inform clinical practice and research, this comprehensive systematic review evaluated diagnostic performances, study cost and patients' experience of different levels of portable sleep studies (type 2, 3, and 4), as well as wearable devices and non-contact systems, in adults. Despite varying study designs and devices used, portable diagnostic tests are found to be sufficient for initial screening of patients at risk of OSA. Future studies are needed to evaluate cost effectiveness with the incorporation of portable diagnostic tests into the diagnostic pathway for OSA, as well as their application in patients with chronic respiratory diseases and other comorbidities that may affect test performance.

The Association between Idiopathic Pulmonary Fibrosis and Obstructive Sleep Apnea: A Systematic Review and Meta-Analysis

The prevalence of obstructive sleep apnea (OSA) has greatly increased in recent years. Recent data suggest that severe and moderate forms of OSA affect between 6 and 17% of adults in the general population. Many papers are reporting the significantly increased prevalence of OSA in patients suffering from fibrotic diseases, including idiopathic pulmonary fibrosis (IPF). Therefore, we performed a systematic review and meta-analysis regarding the dependency between IPF and OSA. Due to the lack of papers focusing on IPF among OSA patients, we focused on the prevalence of OSA among IPF patients. In the search strategy, a total of 684 abstracts were identified, 496 after the removal of duplicates. After the screening of titles and abstracts, 31 studies were qualified for further full-text analysis for eligibility criteria. The final analysis was performed on 614 IPF patients from 18 studies, which met inclusion criteria. There were 469 (76.38%) IPF patients with OSA and 145 (23.62%) without. The mean age varied from 60.9 ± 8.1 up to 70.3 ± 7.9. The obtained prevalence was 76.4 (95% CI: 72.9–79.7) and 75.7 (95% CI: 70.1–80.9) for fixed and random effects, respectively. The median prevalence of OSA among non-IPF patients for all the ethnics groups included in this study was 16,4% (IQR: 3.4%–26.8%). The study provides strong evidence for the increased prevalence of OSA in IPF patients when comparing with the general OSA prevalence.

Obstructive Sleep Apnea as a Risk Factor for COVID-19 Severity-The Gut Microbiome as a Common Player Mediating Systemic Inflammation via Gut Barrier Dysfunction

The novel corona virus that is now known as (SARS-CoV-2) has killed more than six million people worldwide. The disease presentation varies from mild respiratory symptoms to acute respiratory distress syndrome and ultimately death. Several risk factors have been shown to worsen the severity of COVID-19 outcomes (such as age, hypertension, diabetes mellitus, and obesity). Since many of these risk factors are known to be influenced by obstructive sleep apnea, this raises the possibility that OSA might be an independent risk factor for COVID-19 severity. A shift in the gut microbiota has been proposed to contribute to outcomes in both COVID-19 and OSA. To further evaluate the potential triangular interrelationships between these three elements, we conducted a thorough literature review attempting to elucidate these interactions. From this review, it is concluded that OSA may be a risk factor for worse COVID-19 clinical outcomes, and the shifts in gut microbiota associated with both COVID-19 and OSA may mediate processes leading to bacterial translocation via a defective gut barrier which can then foster systemic inflammation. Thus, targeting biomarkers of intestinal tight junction dysfunction in conjunction with restoring gut dysbiosis may provide novel avenues for both risk detection and adjuvant therapy.

Cough in Idiopathic Pulmonary Fibrosis

Chronic cough is experienced by most patients with idiopathic pulmonary fibrosis (IPF). It is often the first symptom and is associated with reduced quality of life, increased rates of depression and anxiety, more severe physiological impairment, and disease progression. Although not fully understood, recent gains in understanding the pathophysiology of chronic cough in IPF have been made. The pathophysiology is likely multifactorial and includes alterations in mucous production and clearance, architectural distortion, and increased cough reflex sensitivity, suggesting a role for targeted therapies and multidisciplinary treatment. Modifiable comorbidities can also induce cough in patients with IPF. There is a renewed emphasis on measuring cough in IPF, with clinical trials of novel and repurposed therapies for chronic cough emerging in this population. This review provides an update on the clinical characteristics, pathophysiology, and measurement of chronic cough in patients with IPF and summarizes recent developments in non-pharmacological and pharmacological therapies.

Nocturnal hypoxaemia in interstitial lung disease: a systematic review

BACKGROUND

Patients with interstitial lung disease (ILD) are at risk of developing nocturnal hypoxaemia due to ventilatory restriction and impaired gas exchange that worsen with supine posture and reduced ventilatory drive during sleep. This systematic review synthesised literature on the diagnostic evaluation, epidemiology, associations, management and prognosis of nocturnal hypoxaemia in ILD.

METHODS

Ovid MEDLINE, Embase and CENTRAL databases were searched for eligible studies. Meta-analyses with subgroup analyses were conducted, where possible.

RESULTS

Fifty-three studies were included (total participant number=2590). The most common definition for clinically significant nocturnal hypoxaemia was ≥10% of total sleep time with oxyhaemoglobin saturation <90%, with pooled prevalence of 37%. There were no significant differences in pooled prevalence according to ILD subtype and comorbid obstructive sleep apnoea status. Study heterogeneity precluded meta-analysis of associations and prognosis. Diffusing capacity for carbon monoxide (DLCO) and echocardiographic features for pulmonary hypertension were consistently associated with nocturnal hypoxaemia. There were inconsistent associations between nocturnal hypoxaemia with ILD subtype and severity. Multivariable analyses in most studies demonstrated significant associations of nocturnal hypoxaemia with survival. Two small short-term intervention studies demonstrated that supplemental oxygen of 1-3 L/min corrected nocturnal hypoxaemia, with improved heart rate control during in-laboratory observation and increased serum antioxidant levels after 1 month of therapy.

CONCLUSION

Nocturnal hypoxaemia is common, associated with DLCO impairment and markers suggestive of pulmonary hypertension, and a potential prognostic factor in patients in ILD. There is a need to establish a consensus definition of nocturnal hypoxaemia and evaluate long-term effects of nocturnal supplemental oxygen in ILD.