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

Associations of early life and childhood risk factors with obstructive sleep apnoea in middle-age

BACKGROUND AND OBJECTIVE

Early-life risk factors for obstructive sleep apnoea (OSA) are poorly described, yet this knowledge may be critical to inform preventive strategies. We conducted the first study to investigate the association between early-life risk factors and OSA in middle-aged adults.

METHODS

Data were from population-based Tasmanian Longitudinal Health Study cohort (n = 3550) followed from 1st to 6th decades of life. Potentially relevant childhood exposures were available from a parent-completed survey at age 7-years, along with previously characterized risk factor profiles. Information on the primary outcome, probable OSA (based on a STOP-Bang questionnaire cut-off ≥5), were collected when participants were 53 years old. Associations were examined using logistic regression adjusting for potential confounders. Analyses were repeated using the Berlin questionnaire.

RESULTS

Maternal asthma (OR = 1.5; 95% CI 1.1-2.0), maternal smoking (OR = 1.2; 1.05, 1.5), childhood pleurisy/pneumonia (OR = 1.3; 1.04, 1.7) and frequent bronchitis (OR = 1.2; 1.01, 1.5) were associated with probable OSA. The risk-factor profiles of 'parental smoking' and 'frequent asthma and bronchitis' were also associated with probable OSA (OR = 1.3; 1.01, 1.6 and OR = 1.3; 1.01-1.9, respectively). Similar associations were found for Berlin questionnaire-defined OSA.

CONCLUSIONS

We found novel temporal associations of maternal asthma, parental smoking and frequent lower respiratory tract infections before the age of 7 years with adult OSA. While determination of their pathophysiological and any causal pathways require further research, these may be useful to flag the risk of OSA within clinical practice and create awareness and vigilance among at-risk groups.

Pulmonary hypertension in the setting of interstitial lung disease: Approach to management and treatment. A consensus statement from the Pulmonary Vascular Research Institute's Innovative Drug Development Initiative-Group 3 Pulmonary Hypertension

Pulmonary hypertension (PH) due to interstitial lung disease (ILD), a commonly encountered complication of fibrotic ILDs, is associated with significant morbidity and mortality. Until recently, the studies of pulmonary vasodilator therapy in PH-ILD have been largely disappointing, with some even demonstrating the potential for harm. This paper is part of a series of Consensus Statements from the Pulmonary Vascular Research Institute's Innovative Drug Development Initiative for Group 3 Pulmonary Hypertension, with prior publications covering pathogenesis, prevalence, clinical features, phenotyping, clinical trials, and impact of PH-ILD. It offers a comprehensive review of and a holistic approach to treatment of PH-ILD, including the management of underlying interstitial lung diseases, importance of treating the comorbidities, emphasis on importance of exercise and palliation of dyspnea, and review of the most up-to-date guidelines for referral for potential lung transplant work up. It also summarizes the prior, ongoing, and possibly future studies in treatment of the vascular derangement of this morbid condition.

Co-existence of OSA and respiratory diseases and the influence of gender

INTRODUCTION

Sleep-disordered breathing (SDB), especially obstructive sleep apnea (OSA), is commonly associated with respiratory diseases, such as COPD, asthma and interstitial lung disease.

AREAS COVERED

This narrative review aims to comprehensively synthesize the existing information on SDB in respiratory diseases, investigate the role of gender in this association, and highlight the importance of OSA management in improving sleep, quality of life, and disease prognosis in these specific patient populations.

EXPERT OPINION

Research indicates a synergistic link between OSA and chronic respiratory diseases, which leads to greater morbidity and mortality compared to each disorder alone. Given the lack of an optimal OSA screening tool for these patients, a comprehensive patient approach and overnight diagnostic sleep study are imperative. Despite the limited evidence available, it seems that gender has an impact on the prevalence, severity, and susceptibility of this coexistence. Recognizing the role of gender in the coexistence of OSA and other respiratory diseases can enhance everyday medical practice and enable clinicians to adopt a more personalized approach toward optimal screening and diagnosis of these patients.

Effects of aging on accompanying intermittent hypoxia in a bleomycin-induced pulmonary fibrosis mouse model

BACKGROUND/AIMS

Obstructive sleep apnea (OSA) is prevalent in older patients with idiopathic pulmonary fibrosis (IPF); however, it is underrecognized. OSA is characterized by intermittent hypoxia (IH) and sleep fragmentation. In this study, we evaluated the effects of IH in an older mouse model of bleomycin-induced lung fibrosis.

METHODS

Bleomycin-induced mice (C57BL/6, female) were randomly divided into four groups of young vs. old and room air (RA)-exposed vs. IH-exposed. Mice were exposed to RA or IH (20 cycles/h, FiO2 nadir 7 ± 0.5%, 8 h/day) for four weeks. The mice were sacrificed on day 28, and blood, bronchoalveolar lavage (BAL) fluid, and lung tissue samples were obtained.

RESULTS

The bleomycin-induced IH-exposed (EBI) older group showed more severe inflammation, fibrosis, and oxidative stress than the other groups. The levels of inflammatory cytokines in the serum and BAL fluid increased in the EBI group. Hydroxyproline levels in the lung tissue increased markedly in the EBI group.

CONCLUSION

This study demonstrates the possible harmful impact of OSA in an elderly mouse model of lung fibrosis. This study further suggests that older patients with IPF and OSA may be more of a concern than younger patients with IPF. Further research is required in this area.

[Consensus guideline on the interdisciplinary diagnosis of interstitial lung diseases]

The evaluation of a patient with interstitial lung disease (ILD) includes assessment of clinical, radiological, and often histopathological data. As there were no specific recommendations to guide the evaluation of patients under the suspicion of an ILD within the German practice landscape, this position statement from an interdisciplinary panel of ILD experts provides guidance related to the diagnostic modalities which should be used in the evaluation of ILD. This includes clinical assessment rheumatological evaluation, radiological examinations, histopathologic sampling and the need for a final discussion in a multidisciplinary team.

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.

Towards Treatable Traits for Pulmonary Fibrosis

Interstitial lung diseases (ILD) are a heterogeneous group of disorders, of which many have the potential to lead to progressive pulmonary fibrosis. A distinction is usually made between primarily inflammatory ILD and primarily fibrotic ILD. As recent studies show that anti-fibrotic drugs can be beneficial in patients with primarily inflammatory ILD that is characterized by progressive pulmonary fibrosis, treatment decisions have become more complicated. In this perspective, we propose that the ‘treatable trait’ concept, which is based on the recognition of relevant exposures, various treatable phenotypes (disease manifestations) or endotypes (shared molecular mechanisms) within a group of diseases, can be applied to progressive pulmonary fibrosis. These targets for medical intervention can be identified through validated biomarkers and are not necessarily related to specific diagnostic labels. Proposed treatable traits are: cigarette smoking, occupational, allergen or drug exposures, excessive (profibrotic) auto- or alloimmunity, progressive pulmonary fibrosis, pulmonary hypertension, obstructive sleep apnea, tuberculosis, exercise intolerance, exertional hypoxia, and anxiety and depression. There are also several potential traits that have not been associated with relevant outcomes or for which no effective treatment is available at present: air pollution, mechanical stress, viral infections, bacterial burden in the lungs, surfactant-related pulmonary fibrosis, telomere-related pulmonary fibrosis, the rs35705950 MUC5B promoter polymorphism, acute exacerbations, gastro-esophageal reflux, dyspnea, and nocturnal hypoxia. The ‘treatable traits’ concept can be applied in new clinical trials for patients with progressive pulmonary fibrosis and could be used for developing new treatment strategies.

Awareness towards the main ILD among primary care physicians

Background: Interstitial lung diseases (ILDs) comprise a group of multiple entities sharing some clinical, functional and radiological similarities. In many countries primary care setting has been devoid of pre- and post-graduate educational interventions focused on basic knowledge on ILD. This, along with usual nonspecificity of symptoms at presentation, may contribute to diagnostic delay in this disease setting.Methods: We designed a study questionnaire to assess the level of awareness on basic diagnostic and management aspects of core ILDs – idiopathic pulmonary fibrosis (IPF), hypersensitivity pneumonitis, sarcoidosis, connective tissue disease related-ILD and drug-induced ILD - among primary care physicians (GPs) from five “ACeS Baixo Vouga” health centres and to perceive possible weaknesses. Differences in awareness between GPs under 45 and over 45 years-old were also assessed.Results: Globally, 69% of questions were correctly answered but only 21.9% of GPs considered to have a satisfactory self-perceived level of knowledge on ILD. Except sarcoidosis (p=0.017) and some isolated questions on other diseases, no significant differences were found between physicians below 45 years and above. Though, there was a trend to higher awareness in the younger group. The best awareness was seen in sarcoidosis. IPF questions had the worst performance and only 48.5% of GPs recognized the importance of velcro-type crackles in suggesting a possible diagnosis.Conclusion: Specific attention should be devoted to educational interventions directed to GPs on basic notions on the main ILDs. This could improve the usual diagnostic delay in many ILDs, as a timely diagnosis is essential for an early treatment and prolonged patient survival.

Obstructive Sleep Apnea with COVID-19

The novel coronavirus disease-2019 (COVID-19) and the ensuing pandemic have greatly impacted the global healthcare system due to its high infectiousness, associated high mortality, and a complete lack of immunity in the population. Globally, the COVID-19 pandemic has unleashed a health crisis that has not only seriously disrupted people's lives but also affected their normal sleep, along with physical and mental health; this situation is especially exacerbated in people suffering from pre-existing conditions, such as sleep apnea. A recent meta-analysis of 18 studies by Miller et al. (September 2020) showed that obstructive sleep apnea (OSA) is related to higher mortality and morbidity in patients with COVID-19 and is most likely independent of other risk factors. A recent meta-analysis indicated that COVID-19 patients with OSA are more severely affected than those without OSA, thereby providing further evidence that concurrent OSA may elevate the severity of COVID-19 infection, along with the risk of mortality. The COVID-19 pandemic has significantly impacted the diagnosis and therapeutic management of patients with OSA. Thus, it is necessary to identify and develop new diagnostic and therapeutic avenues in the future. In this context, the current study summarizes known associations between COVID-19 and OSA and the regular diagnostic and therapeutic strategies for OSA in the light of COVID-19 pandemic prevention and control.

Prevalence and Characteristics of Sleep Apnea in Intensive Care Unit Survivors After SARS-CoV-2 Pneumonia

BACKGROUND

Sleep apnea (SA) was reported as possibly exacerbating symptoms of COVID-19, a disease induced by SARS-CoV-2 virus. The same comorbidities are common with both pathologies. This study aimed to estimate the prevalence, characteristics of SA and variation in AHI three months after severe COVID-19 requiring intensive care unit (ICU) admission.

METHODS

A prospective cohort of patients admitted to ICU for severe COVID-19 underwent an overnight home polygraphy 3 months after onset of symptoms, as part of a comprehensive follow-up program (pulmonary function tests, 6-minute walk tests and chest CT-scan). Patients with an apnea hypopnea index (AHI) ≥5 were considered as having SA. We performed a comparative descriptive analysis of 2 subgroups according to the existence, severity of SA and indication for effective SA treatment: patients with absent or mild SA (AHI <15) vs patients with moderate to severe SA (AHI ≥15).

RESULTS

Among 68 patients included, 62 (91%) had known comorbidities (34 hypertension, 21 obesity, 20 dyslipidemia, 16 type 2 diabetes). It has been observed a preexisting SA for 13 patients (19.1%). At 3 months, 62 patients (91%) had SA with 85.5% of obstructive events. Twenty-four patients had no or a mild SA (AHI <15) and 44 had moderate to severe SA (AHI ≥15). Ischemic heart disease exclusively affected the moderate to severe SA group. Except for thoracic CT-scan which revealed less honeycomb lesions, COVID-19 symptoms were more severe in the group with moderate to severe SA, requiring a longer curarization, more prone position sessions and more frequent tracheotomy.

CONCLUSION

SA involved 91% of patients in our population at 3 months of severe COVID-19 and was mainly obstructive type. Although SA might be a risk factor as well as consequences of ICU care in severe COVID-19 infection, our results underline the importance of sleep explorations after an ICU stay for this disease.

Hypoxia in Cancer and Fibrosis: Part of the Problem and Part of the Solution

Adaptive responses to hypoxia are involved in the progression of lung cancer and pulmonary fibrosis. However, it has not been pointed out that hypoxia may be the link between these diseases. As tumors or scars expand, a lack of oxygen results in the activation of the hypoxia response, promoting cell survival even during chronic conditions. The role of hypoxia-inducible factors (HIFs) as master regulators of this adaptation is crucial in both lung cancer and idiopathic pulmonary fibrosis, which have shown the active transcriptional signature of this pathway. Emerging evidence suggests that interconnected feedback loops such as metabolic changes, fibroblast differentiation or extracellular matrix remodeling contribute to HIF overactivation, making it an irreversible phenomenon. This review will focus on the role of HIF signaling and its possible overlapping in order to identify new opportunities in therapy and regeneration.

Idiopathic pulmonary fibrosis beyond the lung: understanding disease mechanisms to improve diagnosis and management

Idiopathic pulmonary fibrosis (IPF) is a chronic and progressive disorder with an estimated median survival time of 3–5 years after diagnosis. This condition occurs primarily in elderly subjects, and epidemiological studies suggest that the main risk factors, ageing and exposure to cigarette smoke, are associated with both pulmonary and extrapulmonary comorbidities (defined as the occurrence of two or more disorders in a single individual). Ageing and senescence, through interactions with environmental factors, may contribute to the pathogenesis of IPF by various mechanisms, causing lung epithelium damage and increasing the resistance of myofibroblasts to apoptosis, eventually resulting in extracellular matrix accumulation and pulmonary fibrosis. As a paradigm, syndromes featuring short telomeres represent archetypal premature ageing syndromes and are often associated with pulmonary fibrosis. The pathophysiological features induced by ageing and senescence in patients with IPF may translate to pulmonary and extrapulmonary features, including emphysema, pulmonary hypertension, lung cancer, coronary artery disease, gastro-oesophageal reflux, diabetes mellitus and many other chronic diseases, which may lead to substantial negative consequences in terms of various outcome parameters in IPF. Therefore, the careful diagnosis and treatment of comorbidities may represent an outstanding chance to improve quality of life and survival, and it is necessary to contemplate all possible management options for IPF, including early identification and treatment of comorbidities.

A systematic review of COVID-19 and obstructive sleep apnoea

The aims of the study were to review the rapidly emerging COVID-19 literature to determine 1) the relationship between obstructive sleep apnoea (OSA) and adverse COVID-19 outcomes and, 2) potential causal mechanisms 3) what effect COVID-19 has had on OSA diagnosis and 4) what effect COVID-19 has had on treatment and management of OSA during this period. PubMed was systematically searched up to 020620. Studies were included if they had examined the relationship between COVID-19 and OSA. Studies were included that were in English and had the full text available. The findings from this study suggest that many of the risk factors and co-morbidities associated for OSA which include obesity, hypertension and diabetes mellitus are associated with poor COVID-19 outcomes. There are plausible mechanisms by which OSA may independently increase one's risk of morbidity and mortality associated with COVID-19 and data from the newly published CORONADO study suggests that OSA treated patients may be at increased risk of death from COVID-19. It is clear that the pandemic has had a major effect on the treatment management and diagnosis of OSA and moving forward it may be necessary to explore new diagnosis and treatment pathways for these individuals.

Sleep in children and young adults with interstitial and diffuse lung disease

OBJECTIVE

Obstructive sleep apnea (OSA) is common in adult patients with interstitial lung disease (ILD). The aim of the study was to evaluate the prevalence of OSA and sleep quality in children and young adults with children's interstitial and diffuse lung disease (chILD).

METHODS

A polysomnography (PSG) was performed in room air in all consecutive patients followed at a national reference centre between June 2018 and September 2019. Clinical and PSG data were collected.

RESULTS

The PSG data of 20 patients (12 girls, median age 9 (range 0.5-20) years), were analyzed. Seven (35%) patients had pulmonary alveolar proteinosis (PAP), 5 (25%) a disorder of surfactant metabolism, 3 (15%) diffuse pulmonary hemorrhage, 4 (20%) chILD of unknown etiology and one patient had laryngeal and pulmonary sarcoidosis. The median obstructive apnea-hypnea index (OAHI) was normal at 0 events/hour, with a value > 4 events/hour being observed in 2 young adults: an 18-year-old male with PAP and a vital capacity of 27% predicted who had an OAHI of 10.7 events/hour, and a 20-year-old male with laryngeal and pulmonary sarcoidosis who had positional OSA with an OAHI of 19.5 events/hour. The median total sleep time, sleep efficiency, % of wake after sleep onset, and sleep stages were moderately disturbed.

CONCLUSIONS

Moderate or severe OSA was not observed in children <18 years with chILD. Mild or moderate OSA was observed in 2 young adults with PAP and sarcoidosis. As opposed to adults, OSA seems uncommon in children with chILD.

An Integrated Approach Toward the Clinical and Polysomnographic Characteristics of OSA Accompanying IPF

OBJECTIVES

Coincidance of idiopathic pulmonary fibrosis (IPF) and the obstructive sleep apnea syndrome (OSA) may have important effects on the pathogenesis of each other. Our aim is to define clinical characteristics of patients with IPF and OSA and to identify a combined index to determine the severity of both diseases together.

MATERIALS AND METHODS

The clinical and polysomnographic characteristics of 22 patients with OSA and IPF who underwent nocturnal polysomnography (NPSG) were retrospectively evaluated and compared with 23 OSA patients without any other pulmonary comorbidities.

RESULTS

We demonstrated high frequency of OSA within our study group (94,7%) all of whom had at least one of the majör symptoms of OSA. Lower AHI, lower neck circumference, higher percentage of deep sleep (nREM3) and less comorbidities were observed in the study group when compared to OSA with no other pulmonary comorbidities (p<0,05). When restaged into a compound index according to the gender, age and physiology (GAP) index, the patients with mild IPF and OSA showed the same life and sleep quality with the patients who have higher GAP index.

CONCLUSION

All patients with IPF must be questioned for the major symptoms of sleep related breathing disorders (SRBD). Clinical suspicion for OSA must prompt NPSG. With the presence of moderate-severe OSA, the life and sleep quality of patients with mild IPF can be at the same level of patients with severe IPF.

Sleep-related breathing disorders and pulmonary hypertension

Sleep-related breathing disorders (SBDs) include obstructive apnoea, central apnoea and sleep-related hypoventilation. These nocturnal events have the potential to increase pulmonary arterial pressure (PAP) during sleep but also in the waking state. "Pure" obstructive sleep apnoea syndrome (OSAS) is responsible for a small increase in PAP whose clinical impact has not been demonstrated. By contrast, in obesity hypoventilation syndrome (OHS) or overlap syndrome (the association of chronic obstructive pulmonary disease (COPD) with obstructive sleep apnoea (OSA)), nocturnal respiratory events contribute to the development of pulmonary hypertension (PH), which is often severe. In the latter circumstances, treatment of SBDs is essential in order to improve pulmonary haemodynamics.Patients with pulmonary arterial hypertension (PAH) or chronic thromboembolic pulmonary hypertension (CTEPH) are at risk of developing SBDs. Obstructive and central apnoea, as well as a worsening of ventilation-perfusion mismatch, can be observed during sleep. There should be a strong suspicion of SBDs in such a patient population; however, the precise indications for sleep studies and the type of recording remain to be specified. The diagnosis of OSAS in patients with PAH or CTEPH should encourage treatment with continuous positive airway pressure (CPAP). The presence of isolated nocturnal hypoxaemia should also prompt the initiation of long-term oxygen therapy. These treatments are likely to avoid worsening of PH; however, it is prudent not to treat central apnoea and Cheyne-Stokes respiration (CSR) with adaptive servo-ventilation in patients with chronic right-heart failure because of a potential risk of serious adverse effects from such treatment.In this review we will consider the current knowledge of the consequences of SBDs on pulmonary haemodynamics in patients with and without chronic respiratory disease (group 3 of the clinical classification of PH) and the effect of treatments of respiratory events during sleep on PH. The prevalence and consequences of SBDs in PAH and CTEPH (groups 1 and 4 of the clinical classification of PH, respectively), as well as therapeutic options, will also be discussed.

Idiopathic Pulmonary Fibrosis: A Review of Disease, Pharmacological, and Nonpharmacological Strategies With a Focus on Symptoms, Function, and Health-Related Quality of Life

Despite several advances in treatment, idiopathic pulmonary fibrosis (IPF) remains a progressive, symptomatic, and terminal disease in patients not suitable for lung transplantation. With disease progression, IPF often leads to a constellation of symptoms, including dyspnea, cough, anxiety, and depression. Palliative care is appropriate to support these patients. However, traditional curriculum in palliative care has often focused on supporting patients with malignant disease, and clinicians are not universally trained to manage patients with progressive nonmalignant diseases such as IPF. Current antifibrotic therapies aim to slow disease progression but are not able to reduce symptoms or improve daily function and health-related quality of life (HRQL). Palliative care in this patient group requires an understanding of the clinical characteristics of IPF, comorbidities, common medications used, and nonpharmacological strategies that can be undertaken to improve daily function and HRQL. This review focuses on IPF management strategies and their effects on symptoms, exercise tolerance, HRQL, and survival. Pharmacological interactions and considerations related to commonly used palliative care medications are also reviewed. This review highlights the needs of patients with IPF and caregivers, psychosocial function, patient-reported assessment tools, and topics related to advance care planning.

Prevalence and profile of sleep-disordered breathing and obstructive sleep apnea in patients with interstitial lung disease at the pulmonary medicine department of a tertiary care hospital in Mumbai

Background:

Sleep-disordered breathing (SDB), predominantly obstructive sleep apnea (OSA), is a frequent phenomenon in interstitial lung disease (ILD) and may be associated with significant morbidity and mortality.

Methodology:

A prospective, observational, hospital-based study was conducted in a tertiary care hospital after ethics committee permission. The study group consisted of 100 consecutive ILD patients diagnosed by a multidisciplinary diagnosis. They were evaluated for the prevalence of SDB with a polysomnography after a comprehensive history, detailed clinical examination, calculation of various pretest probability scores, and relevant prerequisite workup.

Results:

Out of the total 100 ILD patients, 44 were male (44%) and 56 were female (56%). SDB was present in 57 (57%) patients. Of these, 29 (29%) were found to have only nocturnal oxygen desaturation (NOD), while 28 (28%) had OSA. The 28 cases of OSA were distributed as 15 mild OSA (53.57%), 10 moderate OSA (35.71%), and 3 severe OSA (10.71%). The patients were divided into the following four groups: total study Group (A), patients with OSA (Group B), patients with NOD without OSA (Group C), and no SDB (Group D). The mean forced vital capacity values predicted in the four groups were 53.67%, 50%, 45.56%, and 57.87%, respectively. The mean body mass index in the four groups was 24.56, 27, 26.98, and 24.89 kg/m², respectively. The mean 6-min walk distance in the four groups was 280.7, 250, 256.65, and 311.4 m, respectively. The mean partial pressure of oxygen in the four groups was 65.65, 60, 62.10, and 75.66 mmHg, respectively. The mean apnea–hypopnea index in the study group was 2.98/h, 8.6/h with mild OSA, 21.69/h with moderate OSA, 48.78/h with severe OSA, 3.89/h in patients having NOD without OSA, and 2.54/h in patients with no SDB.

Conclusion:

SDB in ILD is associated with a significant impact on the cardinal determinants of functional capacity, lung function, and quality of life.

The uses of overnight pulse oximetry

Overnight pulse oximetry (OPO) has proven to be an effective and beneficial technique to determine the cardiorespiratory status of patients in both the inpatient and outpatient settings. It is a cheap, safe, reliable, simple, and accurate method of patient monitoring as compared to the expensive and labor-intensive method of multichannel polysomnography for detecting sleep-disordered breathing. It provides accurate information about patient's oxygenation status and also helps in monitoring the response to continuous positive airway pressure and in the surgical treatment of obstructive sleep apnea (OSA). Nocturnal hypoxemia portends a poor prognosis in patients of chronic obstructive pulmonary disease (COPD), interstitial lung disease (ILD), and neuromuscular diseases. OPO can help its early detection and management.

Comorbidities in idiopathic pulmonary fibrosis: an underestimated issue

Idiopathic pulmonary fibrosis (IPF) is a progressive and fibrosing lung disease with a poor prognosis. Between 60% and 70% of IPF patients die of IPF; the remaining causes of death may be due to comorbidities occurring in this ageing population. Interest in the role played by comorbidities in IPF has increased in the past few years. The optimal clinical management of IPF is multifaceted and not only involves antifibrotic treatment, but also vaccinations, oxygen supplementation, evaluation of nutritional status as well as psychological support and patient education. Symptom management, pulmonary rehabilitation, palliative care and treatment of comorbidities represent further areas of clinical intervention. This review analyses the major comorbidities observed in IPF, focusing on those that have the greatest impact on mortality and quality of life (QoL). The identification and treatment of comorbidities may help to improve patients' health-related QoL (i.e. sleep apnoea and depression), while some comorbidities (i.e. lung cancer, cardiovascular diseases and pulmonary hypertension) influence survival. It has been outlined that gathering comorbidities data improves the prediction of survival beyond the clinical and physiological parameters of IPF.

Oxygen therapy in COPD and interstitial lung disease: navigating the knowns and unknowns

Domiciliary oxygen therapy is often prescribed for patients with hypoxaemia due to advanced lung disease, most commonly chronic obstructive pulmonary disease (COPD) and interstitial lung disease (ILD). Long-term oxygen therapy (LTOT) trials conducted in patients with COPD in the 1980s remain the basis for clinical decisions and guideline recommendations regarding LTOT for patients with non-COPD conditions as there is a lack of high-quality evidence concerning its use in the non-COPD population. There is also a lack of evidence for the use of ambulatory and nocturnal oxygen therapy in patients with isolated exertional and nocturnal hypoxaemia. These deficiencies pose significant challenges in patient care, with consequent discrepancies in guideline recommendations and clinical approaches. In recent years, new studies have been and are currently being conducted to fill the gaps in our understanding and use of domiciliary oxygen therapy for other indications, including ILD. This article provides a comparison of the epidemiology and significance of hypoxaemia in patients with COPD and ILD, with an up-to-date review of current evidence regarding the role of different types of domiciliary oxygen therapy in these conditions.

Despite the significance of hypoxaemia in patients with chronic lung diseases, an up-to-date review shows current evidence for clinical use of domiciliary oxygen therapy remains limitedhttp://bit.ly/33aW31n

Sleep and interstitial lung disease

PURPOSE OF REVIEW

There is an increasing recognition of the impact of sleep and sleep disorders on respiratory disease. Recent years have seen a new focus on the relationship between sleep and outcomes in patients interstitial lung disease (ILD).

RECENT FINDINGS

Recent studies suggest a high prevalence of sleep issues in ILD cohorts, which seem to have a meaningful negative impact on quality of life, disease progression, and survival.

SUMMARY

Sleep disordered breathing is common in ILD patients: obstructive sleep apnoea (OSA) is found in 44-72% of ILD patients, and nocturnal hypoxemia is relatively common even in the absence of OSA. Sleep disorders are associated with worse quality of life in ILD, and may also predict more rapid disease progression and increased mortality. It remains unknown if nocturnal hypoxemia may itself cause progression of ILD. Uncontrolled and retrospective studies have suggested that treating OSA may improve ILD-related outcomes, but prospective studies are lacking in this field.

Economic burden of incident interstitial lung disease (ILD) and the impact of comorbidity on costs of care

INTRODUCTION

Evidence about the economic burden related to interstitial lung diseases (ILDs) and the cost-driving factors is sparse. In the knowledge that distinct comorbidities affect the clinical course of ILDs, our study investigates their impact on costs of care within first year after diagnosis.

METHODS

Using claims data of individuals diagnosed with Idiopathic Interstitial Pneumonia (IIP) (n = 14 453) or sarcoidosis (n = 9106) between 2010 and 2013, we calculated total and ILD-associated mean annual per capita costs adjusted by age, sex and comorbidity burden via Generalized Linear Gamma models. Then, we assessed the cost impact of chronic obstructive pulmonary disease (COPD), diabetes, coronary artery disease, depression, gastro-esophageal reflux disease, pulmonary hypertension (PH), obstructive sleep apnoea syndrome (OSAS) and lung cancer using the model-based parameter estimates.

RESULTS

Total mean annual per capita costs were €11 131 in the pooled cohort, €12 111 in IIP and €8793 in sarcoidosis, each with a 1/3 share of ILD-associated cost. Most comorbidities had a significant cost-driving effect, which was most pronounced for lung cancer in total (1.989 pooled, 2.491 sarcoidosis, 1.696 IIP) and for PH in ILD-associated costs (2.606 pooled, 2.347 IIP, 3.648 sarcoidosis). The lung-associated comorbidities COPD, PH, OSAS more strongly affected ILD-associated than total costs.

CONCLUSION

Comorbidities increase the already substantial costs of care in ILDs. To support patient-centred ILD care, not only highly cost-driving conditions that are inherent with high mortality themselves require systematic management. Moreover, conditions that are more rather restricting the patient's activities of daily living should be addressed - despite a low-cost impact.

Management of Chronic Respiratory Failure in Interstitial Lung Diseases: Overview and Clinical Insights

Interstitial lung diseases (ILDs) may be complicated by chronic respiratory failure (CRF), especially in the advanced stages. Aim of this narrative review is to evaluate the current evidence in management of CRF in ILDs. Many physiological mechanisms underlie CRF in ILDs, including lung restriction, ventilation/perfusion mismatch, impaired diffusion capacity and pulmonary vascular damage. Intermittent exertional hypoxemia is often the initial sign of CRF, evolving, as ILD progresses, into continuous hypoxemia. In the majority of the cases, the development of CRF is secondary to the worsening of the underlying disease; however, associated comorbidities may also play a role. When managing CRF in ILDs, the need for pulmonary rehabilitation, the referral to lung transplant centers and palliative care should be assessed and, if necessary, promptly offered. Long-term oxygen therapy is commonly prescribed in case of resting or exertional hypoxemia with the purpose to decrease dyspnea and improve exercise tolerance. High-Flow Nasal Cannula oxygen therapy may be used as an alternative to conventional oxygen therapy for ILD patients with severe hypoxemia requiring both high flows and high oxygen concentrations. Non-Invasive Ventilation may be used in the chronic setting for palliation of end-stage ILD patients, although the evidence to support this application is very limited.

Contractile Activity Is Necessary to Trigger Intermittent Hypobaric Hypoxia-Induced Fiber Size and Vascular Adaptations in Skeletal Muscle

Altitude training has become increasingly popular in recent decades. Its central and peripheral effects are well-described; however, few studies have analyzed the effects of intermittent hypobaric hypoxia (IHH) alone on skeletal muscle morphofunctionality. Here, we studied the effects of IHH on different myofiber morphofunctional parameters, investigating whether contractile activity is required to elicit hypoxia-induced adaptations in trained rats. Eighteen male Sprague-Dawley rats were trained 1 month and then divided into three groups: (1) rats in normobaria (trained normobaric inactive, TNI); (2) rats subjected daily to a 4-h exposure to hypobaric hypoxia equivalent to 4,000 m (trained hypobaric inactive, THI); and (3) rats subjected daily to a 4-h exposure to hypobaric hypoxia just before performing light exercise (trained hypobaric active, THA). After 2 weeks, the tibialis anterior muscle (TA) was excised. Muscle cross-sections were stained for: (1) succinate dehydrogenase to identify oxidative metabolism; (2) myosin-ATPase to identify slow- and fast-twitch fibers; and (3) endothelial-ATPase to stain capillaries. Fibers were classified as slow oxidative (SO), fast oxidative glycolytic (FOG), fast intermediate glycolytic (FIG) or fast glycolytic (FG) and the following parameters were measured: fiber cross-sectional area (FCSA), number of capillaries per fiber (NCF), NCF per 1,000 μm² of FCSA (CCA), fiber and capillary density (FD and CD), and the ratio between CD and FD (C/F). THI rats did not exhibit significant changes in most of the parameters, while THA animals showed reduced fiber size. Compared to TNI rats, FOG fibers from the lateral/medial fields, as well as FIG and FG fibers from the lateral region, had smaller FCSA in THA rats. Moreover, THA rats had increased NCF in FG fibers from all fields, in medial and posterior FIG fibers and in posterior FOG fibers. All fiber types from the three analyzed regions (except the posterior FG fibers) displayed a significantly increased CCA ratio compared to TNI rats. Global capillarisation was also increased in lateral and medial fields. Our results show that IHH alone does not induce alterations in the TA muscle. The inclusion of exercise immediately after the tested hypoxic conditions is enough to trigger a morphofunctional response that improves muscle capillarisation.

Recent advances in managing idiopathic pulmonary fibrosis

Idiopathic pulmonary fibrosis (IPF) is a rare pulmonary disease with a poor prognosis and severe impact on quality of life. Early diagnosis is still challenging and important delays are registered before final diagnosis can be reached. Available tools fail to predict the variable course of the disease and to evaluate response to antifibrotic drugs. Despite the recent approval of pirfenidone and nintedanib, significant challenges remain to improve prognosis and quality of life. It is hoped that the new insights gained in pathobiology in the last few years will lead to further advances in the diagnosis and management of IPF. Currently, early diagnosis and prompt initiation of treatments reducing lung function loss offer the best hope for improved outcomes. This article aims at providing an overview of recent advances in managing patients with IPF and has a particular focus on how to reach a diagnosis, manage comorbidities and lung transplantation, care for the non-pharmacological needs of patients, and address palliative care.

Sleep disorders and health-related quality of life in patients with interstitial lung disease

BACKGROUND

Interstitial lung diseases (ILD) are chronic and restrictive lung diseases with poor survival and quality of life. The aim of this study was to investigate the frequency of sleep disorders in idiopathic pulmonary fibrosis (IPF) and sarcoidosis and to assess patients' quality of life in relation to these disorders.

METHODS

Forty patients, 19 with IPF, and 21 with sarcoidosis stage II/III were included. They were compared with 15 healthy subjects. All patients performed all-night polysomnography (PSG) and completed the Epworth, Berlin, and Stop-Bang questionnaires. In order to evaluate the quality of life, all patients completed the Short-Form 36 (SF-36) questionnaire.

RESULTS

Of the IPF patients, 68% were diagnosed with mild obstructive sleep apnea (OSA), 5.2% with moderate to severe, 5.2% with severe OSA, and 21% with no OSA. Of patients with sarcoidosis, 52.4% were diagnosed with mild OSA and 4.8% with moderate severity OSA. The remaining 42.8% did not have OSA. The health-related quality of life in both patients with IPF and patients with sarcoidosis was impaired especially in the domains concerning physical health and the level of independence, compared to the control group.

CONCLUSIONS

In this sample of patients with IPF and sarcoidosis, obstructive sleep apnea is common at least in a mild degree of severity. The SF-36 questionnaire may be a useful tool for the evaluation of the quality of life in these patients.

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.

OSA and Prolonged Oxygen Desaturation During Sleep are Strong Predictors of Poor Outcome in IPF

PURPOSE

Sleep Breathing Disorders (SBD) are frequently found in idiopathic pulmonary fibrosis (IPF) and they are associated with worse quality of sleep and life and with higher mortality. The study aimed at evaluating the impact of SBD on prognosis (mortality or disease progression) in 35 patients with mild to moderate IPF.

METHODS AND RESULTS

Obstructive sleep apnea (OSA) was diagnosed in 25/35 patients with IPF: 14/35 mild, 7/35 moderate, and 4/35 severe. According to the American Academy of Sleep Medicine (AASM) definition, sleep-related hypoxemia was found in 9/35 patients with IPF. According to the presence/absence of SBD, IPF patients were divided into 4 groups: NO-SBD group (Group A, 25.7%), OSA without sleep-related hypoxemia (Group B, 48.5%), OSA with sleep-related hypoxemia group (Group C, 22.8%), and only 1/35 had sleep-related hypoxemia without OSA(Group D, 2.8%). Statistical analysis was focused only on group A, B, and C. Patients with OSAS and sleep-related hypoxemia (Group C) had the worse prognosis, both in terms of mortality or clinical deterioration. SBD were the only independent risk factor (Cox Proportional Hazards Multiple Regression Analysis) for mortality (HR 7.6% IC 1.2-36.3; p = 0.029) and disease progression (HR 9.95% IC 1.8-644.9; p = 0.007).

CONCLUSIONS

SBD are associated with a worse prognosis, both in terms of mortality or clinical progression. The presence of SBD should be explored in all IPF patients.

Pulmonary fibrosis, part I: epidemiology, pathogenesis, and diagnosis

INTRODUCTION

Many forms of interstitial lung disease (ILD) can progress to extensive fibrosis and respiratory failure. Idiopathic pulmonary fibrosis (IPF), which generally has a poor prognosis, has been thoroughly studied over the past two decades, and many important discoveries have been made that pertain to genetic predisposition, epidemiology, disease pathogenesis, diagnosis, and management. Additionally, non-IPF forms of ILD can have radiologic and histopathologic manifestations that mimic IPF, and making an accurate diagnosis is key to providing personalized medicine to patients with pulmonary fibrosis. Areas covered: This manuscript discusses current knowledge pertaining to the genetics, epidemiology, pathogenesis, and diagnosis of pulmonary fibrosis with an emphasis on IPF. The material upon which this discussion is based was obtained from various published texts and manuscripts identified via literature searching (e.g. PubMed). Expert commentary: Many genetic variants have been identified that are associated with risk of developing pulmonary fibrosis, and an improved understanding of the influence of both genomic and epigenomic factors in the development of pulmonary fibrosis is rapidly evolving. Because many forms of fibrosing ILD can have similar radiologic and histopathologic patterns yet have different responses to therapeutic interventions, making an accurate diagnosis of specific forms of pulmonary fibrosis is increasingly important.

The clinical impact of major comorbidities on idiopathic pulmonary fibrosis

Idiopathic pulmonary fibrosis (IPF) is a progressive and devastating disease with a median survival time of 2-3 years after diagnosis. Patients with IPF exhibit distinct patterns of disease progression, and some patients display a more rapidly progressive clinical course. The clinical course of IPF may also include periods of acute deterioration, which are termed acute exacerbations. Patients with IPF frequently experience various comorbidities, such as pulmonary infection, emphysema, pulmonary hypertension, lung cancer, gastroesophageal reflux, cardiovascular disease, diabetes mellitus, and obstructive sleep apnea. A previous age- and sex-matched study showed that IPF itself was an independent risk factor for these comorbidities. Other studies have demonstrated that these comorbidities are associated with disease progression and mortality in IPF. These variations in the clinical course and comorbidities have affected the researchers' and physicians' understanding of IPF. Therefore, better identification and understanding of these variations may be helpful when making decisions regarding therapeutic interventions. Furthermore, the identification and treatment of comorbidities may have a clinically significant impact on patient survival. Future studies should use well-established definitions for distinct progression patterns and comorbid conditions to obtain greater insights into the pathogenesis and treatment of IPF.

Sleep apnoea

Sleep apnoea is a disorder characterised by repetitive pauses in breathing during sleep caused by airway occlusion (obstructive sleep apnoea) or altered control of breathing (central sleep apnoea). In this Clinical Year in Review, we summarise high-impact research from the past year pertaining to management, diagnosis and cardio-metabolic consequences of sleep apnoea.