Sleep and respiratory sleep disorders in idiopathic pulmonary fibrosis

Oxygen therapy for exercise capacity in fibrotic interstitial lung disease: A systematic review and meta-analysis of randomised controlled trials

BACKGROUND

Fibrotic interstitial lung disease (fILD) is characterised primarily by impaired lung function and quality of life. The present study investigated whether oxygen therapy could improve exercise capacity among patients with fILD.

METHODS

Previously published randomised controlled trials (RCTs) were surveyed. A systematic review and meta-analysis was conducted to evaluate the effectiveness of oxygen therapy in improving the exertional capacity of patients with fILD. The primary outcome was peripheral oxygen saturation (SpO2) during exercise. The effects of oxygen therapy on fatigue, dyspnoea, heart rate, and exercise duration or distance were also analysed.

RESULTS

Fourteen RCTs involving 370 patients were included. Oxygen therapy improved SpO2 during exercise (mean difference, MD = 6.26 %), exercise duration (MD = 122.15 s), fatigue (standard mean difference, SMD = -0.30), and dyspnoea (MD = -0.75 Borg score units). High-flow oxygen systems tended to be more effective than low-flow systems in improving exercising SpO2, duration, fatigue, dyspnoea, and heart rate. High-flow nasal cannulas (HFNCs) yielded better outcomes regarding SpO2 and fatigue than did high-flow Venturi masks (MD = 1.60 % and MD = -1.19 Borg score units, respectively). No major adverse events were reported.

CONCLUSION

The evidence from RCTs supports the short-term use of oxygen supplementation to improve SpO2, exercise capacity, fatigue, and dyspnoea among patients with fILD. Further analyses demonstrates that HFNCs yield more favourable outcomes, yet not reaching statistical significance except for improving SpO2 and fatigue. However, the long-term effects of oxygen therapy on quality of life and mortality remain unclear.

The impact of sleep duration on physical activity in daily life in patients with idiopathic pulmonary fibrosis

BACKGROUND

Despite the high prevalence of sleep disturbances in idiopathic pulmonary fibrosis (IPF), the relationship between physical activity in daily life (PADL) and sleep in this population remains unclear.

OBJECTIVES

Investigate the impact of sleep on different domains of PADL in IPF and characterize their PADL profile.

METHODS

Sixty-seven participants (thirty-three with IPF and thirty-four healthy subjects [control group]) were included. The subjects underwent assessments of pulmonary function, exercise capacity, respiratory and peripheral muscle strength, PADL, sleep, dyspnea, and health-related quality of life. PADL and sleep measures were assessed using an activity monitor (Actigraph®, wGT3x-BT). Associations between sleep and PADL were done using correlation and regression models.

RESULTS

In the IPF, sleep duration at night associated significantly with step counts, sedentary, light, and moderate-to-vigorous physical activity (MVPA) (-0.82 ≤ R ≤ 0.43; p < .05 for all). Lung function and sleep partially explained PADL variables (0.19 ≤ R2 ≤ 0.65, p < .05 for all). Compared to controls, the IPF subjects presented lower step counts, less time spent in MVPA, standing position, and more time spent in lying position (p < .05, for all).

CONCLUSIONS

Sleep duration is associated with PADL in IPF. The PADL profile of patients is worse than in control subjects.

Intermittent hypoxia increases ROS/HIF-1α 'related oxidative stress and inflammation and worsens bleomycin-induced pulmonary fibrosis in adult male C57BL/6J mice

Obstructive sleep apnea (OSA) has been increasingly recognized as a risk factor for idiopathic pulmonary fibrosis (IPF). The intermittent hypoxia (IH) and re-oxygenation of OSA contribute to poor outcomes of IPF, however, the potential mechanism remains unknown. Here, C57BL/6J mice were administered intratracheal injection of Bleomycin (BLM) or saline and then exposed to IH (alternating cycles of FiO2 21% for 60S and FiO2 10% for 30 s, 40 cycles/hour, 8 h/day) to mimic OSA or intermittent air (IA) for 4 days, 8 days or 21 days. This study found that pulmonary fibrosis in BLM + IH treated mice was more severe than that in BLM + IA group at day 8 and 21, but not observed at day 4. Besides, the expression of reactive oxygen species (ROS) and hypoxia inducible factor-1α (HIF-1α),which are related to hypoxia reduced oxidative stress and inflammation, were higher in BLM + IH treated mice than BLM + IA mice, and IH increased these indexes in BLM treated mice from day 4 to day 21. Interestingly, a positive linear correlation between the HIF-1α expression and hydroxyproline (HYP) content was observed. We further found some inflammatory cells in bronchoalveolar lavage fluid were increased significantly from day 4 to 21, and there was a positive correlation between inflammation and ROS expression. Our results demonstrated that IH aggravated BLM-induced pulmonary fibrosis, and ROS/HIF-1α related oxidative stress and inflammation involved. The increase of ROS/HIF-1α related oxidative stress and inflammation may be a potential mechanism of moderate-to-severe OSA in potentiating pulmonary fibrosis of IPF, which warrants further study.

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.

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.

Fatigue in idiopathic pulmonary fibrosis measured by the Fatigue Assessment Scale during antifibrotic treatment

Background: Fatigue is a common complaint in patients with idiopathic pulmonary fibrosis (IPF) and has been reported in a considerable percentage of patients. Fatigue is also a registered side effect of pirfenidone, one of two approved antifibrotic drugs. The Fatigue Assessment Scale (FAS) was developed for assessment of fatigue in sarcoidosis and validated in patients with sarcoidosis. FAS has been used in a few IPF studies but has not been validated. Aims: To study the change in FAS after initiation of pirfenidone or nintedanib in the treatment of patients with IPF during a six-month period. Methods: Between April 2017 and January 2018, all incident patients with IPF starting antifibrotic treatment were invited to complete FAS before, four weeks, three, and six months after initiation of antifibrotic treatment. Baseline characteristics including lung function were registered. Results: Fifty-two patients were included, mean FVC% 84.8, mean DLCO% 51.4. Nintedanib was started in 25 patients; 27 patients started pirfenidone. Sixty-four percent of patients had a FAS score >22 indicating substantial fatigue at baseline. There was no statistically significant difference in FAS score for patients treated with nintedanib or pirfenidone at any time point. FAS score increased statistically significantly during the six-month follow-up. This change was driven by patients without substantial fatigue at baseline with an increase in FAS score of 8.4 points; patients with substantial fatigue at baseline experienced no statistically significant change. Conclusion: A majority of patients with IPF suffered from substantial fatigue at the time of diagnosis. Fatigue progressed over time and increasing fatigue was associated with younger age, nintedanib treatment and low degree of fatigue at baseline. There was no significant difference in FAS score between the two antifibrotic treatments at any time point, even though fatigue is not a registered side effect in nintedanib.

Restless legs syndrome: A new comorbidity in idiopathic pulmonary fibrosis

OBJECTIVE

Sleep disorders have a high prevalence among patients with idiopathic pulmonary fibrosis (IPF). The prevalence of restless legs syndrome (RLS) is not known in these patients, neither is its clinical impact as a comorbidity. We investigated the association of RLS with IPF and characterized the clinical features of RLS in a cohort of IPF patients.

METHODS

Fifty patients with diagnosis of IPF were prospectively enrolled. RLS was diagnosed using the validated 5-item RLS criteria. Sleep quality was evaluated using the Pittsburgh Sleep Quality Index. The prevalence of RLS in the IPF group was compared to that observed in a group of 293 patients referred for suspect of sleep disorders. The relationships between RLS and clinical parameters were determined using multivariate logistic regression.

RESULTS

Prevalence of RLS in the IPF group was significantly higher than in the control population of patients referred for sleep disorders (IPF: 24%, controls 10%: χ² 6.49, p = 0.011). Higher PSQI score confirmed to be associated with RLS after adjusting for demographics and clinical parameters of disease severity (OR = 1.38, 95%CI 1.08-1.76; p = 0.01).

CONCLUSIONS

RLS is highly prevalent in IPF and significantly worsen sleep quality in these patients. The benefit/risk ratio of a specific therapeutic intervention for RLS in IPF should be assessed in further prospective research.

Non-invasive Ventilation for Children With Chronic Lung Disease

Advances in medical care and supportive care options have contributed to the survival of children with complex disorders, including children with chronic lung disease. By delivering a positive pressure or a volume during the patient's inspiration, NIV is able to reverse nocturnal alveolar hypoventilation in patients who experience hypoventilation during sleep, such as patients with chronic lung disease. Bronchopulmonary dysplasia (BPD) is a common complication of prematurity, and despite significant advances in neonatal care over recent decades its incidence has not diminished. Most affected infants have mild disease and require a short period of oxygen supplementation or respiratory support. However, severely affected infants can become dependent on positive pressure support for a prolonged period. In case of established severe BPD, respiratory support with non-invasive or invasive positive pressure ventilation is required. Patients with cystic fibrosis (CF) and advanced lung disease develop hypoxaemia and hypercapnia during sleep and hypoventilation during sleep usually predates daytime hypercapnia. Hypoxaemia and hypercapnia indicates poor prognosis and prompts referral for lung transplantation. The prevention of respiratory failure during sleep in CF may prolong survival. Long-term oxygen therapy has not been shown to improve survival in people with CF. A Cochrane review on the use NIV in CF concluded that NIV in combination with oxygen therapy improves gas exchange during sleep to a greater extent than oxygen therapy alone in people with moderate to severe CF lung disease. Uncontrolled, non-randomized studies suggest survival benefit with NIV in addition to being an effective bridge to transplantation. Complications of NIV relate mainly to prolonged use of a face or nasal mask which can lead to skin trauma, and neurodevelopmental delay by acting as a physical barrier to social interaction. Another associated risk is pulmonary aspiration caused by vomiting whilst wearing a face mask. Adherence to NIV is one of the major barriers to treatment in children. This article will review the current evidence for indications, adverse effects and long term follow up including adherence to NIV in children with chronic lung disease.

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.

Diagnosing complications and co-morbidities of fibrotic interstitial lung disease

Introduction: Interstitial lung diseases (ILDs) represent a heterogeneous group of rare disorders that include more than 200 entities, mostly associated with high mortality. In recent years, the progress regarding the understanding of the pathogenesis of these diseases led to the approval of specific treatments. In ILDs, the presence of comorbidities has a significant impact on the quality of life and the survival of patients and, therefore, their diagnosis and treatment has a pivotal role in management and could improve overall outcome. Areas covered: We discuss key diagnostic issues with regard to the most frequent comorbidities in ILDs. Treatment options are also discussed as the decision to investigate more definitively in order to identify specific comorbidities (including lung cancer, pulmonary hypertension, GE reflux, and obstructive sleep apnoea) is critically dependent upon whether comorbidity-specific treatments are likely to be helpful in individual patients, judged on a case by case basis. Expert opinion: The extent to which clinicians proactively pursue the identification of comorbidities depends on realistic treatment goals in individual patients.

Relation of Warrick Score and Polysomnographic Parameters in Patients with Interstitial Lung Disease

Background

Obstructive sleep apnea (OSA) is often reported in connection with interstitial lung disease. As yet, there is insufficient data on the association of OSA severity parameters with lung involvement. We purposed to assess the frequency of OSA in our study group and to investigate the relationship between radiological involvement and OSA severity parameters.

Material/Methods

The study included 79 patients with interstitial lung disease who underwent spirometry, a carbon monoxide diffusion test (DLCO), high-resolution computed tomography, and polysomnography. The data were analyzed using SPSS 22 software.

Results

Of the 79 patients, 53 patients (67.1%) had OSA, and there was a negative correlation between DLCO and the mean time spent with oxygen saturation levels below 90% (r=−0.686, P=0.001). The Warrick score was used as an indicator of the extent and severity of pulmonary involvement and was positively correlated with the apnea-hypopnea index, oxygen desaturation index, and the mean time spent with oxygen saturation below 90% (r=0.275, P=0.014; r=0.264 P=0.019; r=0.235, P=0.038).

Conclusions

In our study, a significant relationship was found between the Warrick score and the OSA severity parameters, as determined by polysomnography. Polysomnographic examinations might be useful, especially in patients with a Warrick score greater than 15, to avoid possible complications.

TNFRSF11B: A potential plasma biomarker for diagnosis of obstructive sleep apnea

BACKGROUND

Obstructive sleep apnea (OSA) was characterized by chronic intermittent hypoxia, which was an independent risk factor for endothelial dysfunction. Circulating TNFRSF11B might play an important role in promoting endothelial cells dysfunction. We explored the role of plasma TNFRSF11B as a potential mechanism of endothelial dysfunction in OSA patients.

METHODS

The study population consisted of 120 patients with varying severity of OSA and 40 control subjects. Plasma TNFRSF11B levels were measured using human Magnetic Luminex assay.

RESULTS

Our data showed that plasma TNFRSF11B levels were significantly higher in patients with OSA. After adjusting confounding factors, plasma TNFRSF11B levels were independently associated with the presence of OSA (Beta:0.434, 95% CI: 664.096 to 1076.247; P < 0.001) and plasma TNFRSF11B levels were positively associated with the apnea-hypopnea index (Beta:0.486, 95% CI: 0.007 to 0.017; P < 0.001). Furthermore, plasma TNFRSF11B showed higher discriminatory accuracy in predicting the presence of OSA (AUC:0.964).

CONCLUSIONS

Plasma TNFRSF11B levels were significantly associated with the presence of OSA and its severity. TNFRSF11B could be a plasma biomarker with a positive diagnostic value for premature vascular endothelial dysfunction in patients with OSA.

Intermittent Hypoxia Increases the Severity of Bleomycin-Induced Lung Injury in Mice

Background

Severe obstructive sleep apnea (OSA) with chronic intermittent hypoxia (IH) is common in idiopathic pulmonary fibrosis (IPF). Here, we evaluated the impact of IH on bleomycin- (BLM-) induced pulmonary fibrosis in mice.

Methods

C57BL/6J mice received intratracheal BLM or saline and were exposed to IH (40 cycles/hour; FiO₂ nadir: 6%; 8 hours/day) or intermittent air (IA). In the four experimental groups, we evaluated (i) survival; (ii) alveolar inflammation, pulmonary edema, lung oxidative stress, and antioxidant enzymes; (iii) lung cell apoptosis; and (iv) pulmonary fibrosis.

Results

Survival at day 21 was lower in the BLM-IH group (p < 0.05). Pulmonary fibrosis was more severe at day 21 in BLM-IH mice, as assessed by lung collagen content (p = 0.02) and histology. At day 4, BLM-IH mice developed a more severe neutrophilic alveolitis, (p < 0.001). Lung oxidative stress was observed, and superoxide dismutase and glutathione peroxidase expression was decreased in BLM-IH mice (p < 0.05 versus BLM-IA group). At day 8, pulmonary edema was observed and lung cell apoptosis was increased in the BLM-IH group.

Conclusion

These results show that exposure to chronic IH increases mortality, lung inflammation, and lung fibrosis in BLM-treated mice. This study raises the question of the worsening impact of severe OSA in IPF patients.

Idiopathic pulmonary fibrosis: pathogenesis and management

Background

Idiopathic pulmonary fibrosis (IPF) is a chronic, progressive disease characterized by the aberrant accumulation of fibrotic tissue in the lungs parenchyma, associated with significant morbidity and poor prognosis. This review will present the substantial advances achieved in the understanding of IPF pathogenesis and in the therapeutic options that can be offered to patients, and will address the issues regarding diagnosis and management that are still open.

Main body

Over the last two decades much has been clarified about the pathogenic pathways underlying the development and progression of the lung scarring in IPF. Sustained alveolar epithelial micro-injury and activation has been recognised as the trigger of several biological events of disordered repair occurring in genetically susceptible ageing individuals. Despite multidisciplinary team discussion has demonstrated to increase diagnostic accuracy, patients can still remain unclassified when the current diagnostic criteria are strictly applied, requiring the identification of a Usual Interstitial Pattern either on high-resolution computed tomography scan or lung biopsy.

Outstanding achievements have been made in the management of these patients, as nintedanib and pirfenidone consistently proved to reduce the rate of progression of the fibrotic process. However, many uncertainties still lie in the correct use of these drugs, ranging from the initial choice of the drug, the appropriate timing for treatment and the benefit-risk ratio of a combined treatment regimen. Several novel compounds are being developed in the perspective of a more targeted therapeutic approach; in the meantime, the supportive care of these patients and their carers should be appropriately prioritized, and greater efforts should be made toward the prompt identification and management of relevant comorbidities.

Conclusions

Building on the advances in the understanding of IPF pathobiology, the further investigation of the role of gene variants, epigenetic alterations and other molecular biomarkers reflecting disease activity and behaviour will hopefully enable earlier and more confident diagnosis, improve disease phenotyping and support the development of novel agents for personalized treatment of IPF.

Physiology of the lung in idiopathic pulmonary fibrosis

The clinical expression of idiopathic pulmonary fibrosis (IPF) is directly related to multiple alterations in lung function. These alterations derive from a complex disease process affecting all compartments of the lower respiratory system, from the conducting airways to the lung vasculature. In this article we review the profound alterations in lung mechanics (reduced lung compliance and lung volumes), pulmonary gas exchange (reduced diffusing capacity, increased dead space ventilation, chronic arterial hypoxaemia) and airway physiology (increased cough reflex and increased airway volume), as well as pulmonary haemodynamics related to IPF. The relative contribution of these alterations to exertional limitation and dyspnoea in IPF is discussed.

Physiological impairment in IPF is complex and involves all compartments of the respiratory systemhttp://ow.ly/gyao30hdHUb

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.

Síndrome de apnea-hipopnea obstructiva del sueño y enfermedades respiratorias

El síndrome de apnea-hipopnea obstructiva del sueño (SAHOS) es una enfermedad sistémica con afectación de múltiples órganos. El presente artículo trata la relación que existe entre el SAHOS y algunas enfermedades que comprometen el sistema respiratorio como son la enfermedad pulmonar obstructiva crónica, el asma, la tos crónica, el síndrome de hipoventilación alveolar y la fibrosis pulmonar. Por lo general, cada una de estas afectaciones se diagnostica por separado, pero es importante conocer su relación de coexistencia para definir la necesidad de realizar estudios del sueño diagnósticos a los pacientes con enfermedades respiratorias, en especial cuando hay un grado desproporcionado de hipertensión pulmonar al esperado por solo la presencia de la enfermedad respiratoria.

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.

Obstructive sleep apnoea and related comorbidities in incident idiopathic pulmonary fibrosis

The objectives of this prospective study were: 1) to determine the prevalence and determinants of obstructive sleep apnoea (OSA) in patients with newly diagnosed idiopathic pulmonary fibrosis (IPF); 2) to determine whether OSA was associated with cardiovascular disease (CVD) as well as increased oxidative stress and levels of IPF biomarkers in the blood.

A group of 45 patients with newly diagnosed IPF attended polysomnography. The prevalence of CVD and the severity of coronary artery calcification were investigated by high-resolution computed tomography. The levels of 8-hydroxydeoxyguanosine (8-OH-DG) and various IPF biomarkers in the blood were compared between patients with no or mild OSA (apnoea–hypopnoea index (AHI) <15 events·h−1), with moderate OSA (15 ≤AHI <30 events·h−1) and with severe OSA (AHI ≥30 events·h−1).

The prevalence of moderate-to-severe OSA and severe OSA was 62% and 40%, respectively. AHI did not correlate with demographic or physiological data. All patients with severe OSA had a medical history of CVD,versus41.2% and 40% of those with no or mild OSA, or with moderate OSA, respectively (p<0.0001). Ischaemic heart disease (IHD) and moderate-to-severe coronary artery calcifications were strongly associated with severe OSA. The 8-OH-DG and matrix metalloproteinase-7 serum levels were significantly increased in the severe OSA group.

Moderate-to-severe OSA is highly prevalent in incident IPF and severe OSA is strongly associated with the presence of CVD, particularly IHD.

Comorbidities in interstitial lung diseases

Fibrosing lung disorders include a large number of diseases with diverse behaviour. Patients can die because of the progression of their illness, remain stable or even improve after appropriate treatment has been instituted. Comorbidities, such as acute and chronic infection, gastro-oesophageal reflux, pulmonary hypertension, lung cancer, cardiovascular diseases, and obstructive sleep apnoea, can pre-exist or develop at any time during the course of the disease and, if unidentified and untreated, may impair quality of life, impact upon the respiratory status of the patients, and ultimately lead to disease progression and death. Therefore, early identification and accurate treatment of comorbidities is essential.

The association between health-related quality of life and disease progression in idiopathic pulmonary fibrosis: a prospective cohort study

Background and objective: Generally, a disease-specific health-related quality of life (HRQOL) measurement is more useful than generic measures in assessing perceived physical and mental health characteristic of a particular disease. The idiopathic pulmonary fibrosis (IPF)-specific version of St. George’s Respiratory Questionnaire (SGRQ-I) has been recently developed for patients with IPF. We proposed to evaluate associations between the SGRQ-I and other clinical indices, as well as its prognostic value in patients with IPF. Methods: Fifty-two patients with IPF were recruited in this prospective cohort study. HRQOL was assessed using the SGRQ-I and the Medical Outcomes Study 36-item Short Form, dyspnea using the modified Medical Research Council (mMRC) dyspnea scale, and psychological status using the Hospital Anxiety and Depression Scale (HADS). We then evaluated the relationship between the SGRQ-I and other clinical measures, as well as one-year clinical deterioration defined as a hospital admission due to respiratory exacerbation or all-cause death. Results: Stepwise multiple-regression analyses revealed that the mMRC dyspnea scale, the HADS anxiety or depression, and minimum oxygen saturation during a six-minute walk test significantly contributed to the Total and three components of the SGRQ-I. In multivariate Cox proportional-hazards analyses, the Total score of SGRQ-I predicted clinical deterioration independent of forced vital capacity, the six-minute walk distance, or partial pressure of arterial oxygen on room air. Conclusions: The SGRQ-I is a multidisciplinary instrument representing physical, functional and psychological impairments in patients with IPF. The SGRQ-I is a significant predictor of short-term disease progression independent of physiological measurements. (Sarcoidosis Vasc Diffuse Lung Dis 2017; 34: 226-235)

Tissue remodelling in pulmonary fibrosis

Many lung diseases result in fibrotic remodelling. Fibrotic lung disorders can be divided into diseases with known and unknown aetiology. Among those with unknown aetiology, idiopathic pulmonary fibrosis (IPF) is a common diagnosis. Because of its progressive character leading to a rapid decline in lung function, it is a fatal disease with poor prognosis and limited therapeutic options. Thus, IPF has motivated many studies in the last few decades in order to increase our mechanistic understanding of the pathogenesis of the disease. The current concept suggests an ongoing injury of the alveolar epithelium, an impaired regeneration capacity, alveolar collapse and, finally, a fibroproliferative response. The origin of lung injury remains elusive but a diversity of factors, which will be discussed in this article, has been shown to be associated with IPF. Alveolar epithelial type II (AE2) cells play a key role in lung fibrosis and their crucial role for epithelial regeneration, stabilisation of alveoli and interaction with fibroblasts, all known to be responsible for collagen deposition, will be illustrated. Whereas mechanisms of collagen deposition and fibroproliferation are the focus of many studies in the field, the awareness of other mechanisms in this disease is currently limited to biochemical and imaging studies including quantitative assessments of lung structure in IPF and animal models assigning alveolar collapse and collapse induration crucial roles for the degradation of the lung resulting in de-aeration and loss of surface area. Dysfunctional AE2 cells, instable alveoli and mechanical stress trigger remodelling that consists of collapsed alveoli absorbed by fibrotic tissue (i.e., collapse induration).