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

Exploring the Role of Hemogram-Derived Ratios and Liver Fibrosis Scores in Pulmonary Fibrosis

Background and Objectives: Pulmonary fibrosis, including idiopathic pulmonary fibrosis (IPF) and secondary pulmonary fibrosis (SPF), is a progressive lung disease that significantly impairs respiratory function. Accurate differentiation between IPF and SPF is crucial for effective management. This study explores the association between pulmonary fibrosis and hepatic conditions, evaluating the utility of various hemogram-derived ratios and hepatic fibrosis scores in distinguishing between IPF and SPF. Materials and Methods: We conducted a retrospective study involving patients diagnosed with IPF or SPF at the "Leon Daniello" Clinical Hospital of Pneumology in Cluj-Napoca, Romania. Pulmonary fibrosis was confirmed via imaging techniques, and hepatic steatosis and fibrosis were assessed using non-invasive scores. We analyzed clinical, laboratory, and pulmonary function data, focusing on hemogram-derived ratios and hepatic scores. Statistical analyses, including ROC curves, were used to evaluate the effectiveness of these biomarkers in differentiating IPF from SPF. Results: We included a total of 38 patients with IPF and 28 patients with SPF. Our findings revealed that IPF patients had a significantly higher FIB-4 score compared to SPF patients, suggesting increased hepatic fibrosis risk in IPF, as well as an increased RDW/PLT ratio. Conversely, SPF patients exhibited elevated PLR, PNR, and SII, reflecting a more pronounced inflammatory profile. PLR and PNR demonstrated the highest discriminatory ability between IPF and SPF, while traditional hepatic fibrosis scores showed limited differentiation capabilities. No significant differences in pulmonary function tests were observed across hepatic fibrosis risk categories. Conclusions: The study highlights the value of biomarkers like PLR and PNR in differentiating between IPF and SPF, offering additional diagnostic insights beyond traditional imaging. Integrating hepatic assessments into the management of pulmonary fibrosis could improve diagnostic accuracy and patient care.

Knowledge and Attitudes Toward Obstructive Sleep Apnea Among Korean Pulmonologists: A Nationwide Survey

BACKGROUND

Obstructive sleep apnea (OSA) significantly impacts cardiovascular, metabolic, and respiratory health. In Korea, OSA patients are treated by specialists in internal medicine, otolaryngology, neurology, and psychiatry, but the participation rate of pulmonologists in OSA management is relatively low compared to other specialties. This study investigated the knowledge and attitudes about OSA among Korean pulmonologists.

MATERIALS AND METHODS

An online survey was conducted, targeting respiratory specialists listed in the Korean Academy of Tuberculosis and Respiratory Diseases directory. The survey used the validated "Obstructive Sleep Apnea Knowledge and Attitudes" (OSAKA) questionnaire, which consists of questions about knowledge and attitudes on OSA. To maximize participation, email invitations were sent three times to the target audience.

RESULTS

Out of 634 queried pulmonologists, 127 (20%) responded to the survey. The mean age of respondents was 45.4 ± 8.6 years. The respondents' years of specialty acquisition ranged from the 1980s to the 2010s. Additionally, 74 (58.3%) held a doctor's degree, and 96 (75.6%) worked in hospitals with a sleep center. Furthermore, 71 (55.9%) of the pulmonologists reported having experience with OSA patients. Pulmonologists with experience managing OSA patients had significantly higher knowledge and attitude scores compared to those without such experience. Interestingly, older respondents and those who completed their pulmonology training earlier had higher attitude scores. In addition, the knowledge score significantly correlated with responses to the five items of the attitude questionnaire.

CONCLUSION

This study provides valuable insights into the knowledge and attitudes of Korean pulmonologists regarding OSA. The findings indicate that their knowledge levels are comparable to or better than those in previous studies. These results underscore the need for targeted educational programs and practical training, especially for younger pulmonologists, to enhance their proficiency in managing OSA and to encourage a more active role in its treatment.

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.

The role of microRNAs in pathophysiology and diagnostics of metabolic complications in obstructive sleep apnea patients

Obstructive sleep apnea (OSA) is one of the most common sleep disorders, which is characterized by recurrent apneas and/or hypopneas occurring during sleep due to upper airway obstruction. Among a variety of health consequences, OSA patients are particularly susceptible to developing metabolic complications, such as metabolic syndrome and diabetes mellitus type 2. MicroRNAs (miRNAs) as epigenetic modulators are promising particles in both understanding the pathophysiology of OSA and the prediction of OSA complications. This review describes the role of miRNAs in the development of OSA-associated metabolic complications. Moreover, it summarizes the usefulness of miRNAs as biomarkers in predicting the aforementioned OSA complications.

Prognostic Significance of Obstructive Sleep Apnea in a Population of Subjects with Interstitial Lung Diseases

INTRODUCTION

Obstructive sleep apnea (OSA) is often observed in subjects with interstitial lung disease (ILD). It may have a negative impact on the course of ILD, but its prognostic significance in relation to other known indicators of poor outcome is unclear.

METHODS

After a detailed work-up, including overnight unattended type III polygraphy, all subjects newly diagnosed with ILDs referred to our clinics were followed-up for at least 1.5 years or until death or progression of disease [> 10% decline in forced vital capacity (FVC) below baseline]. We analyzed relationships between some prespecified variables of interest, including sleeping results, to establish parameters predictive of progressive course.

RESULTS

Our population consisted of 46 subjects (mean age 59.6 years; males 61%); 23.9% and 41% had idiopathic pulmonary fibrosis and ILD associated with systemic diseases, respectively. Mean baseline forced vital capacity and diffusion capacity of carbon monoxide were 83% and 57% of predicted, respectively. Mean (± SE) Apnea-Hypopnea Index (AHI) was 17 (± 3) events/h. AHI in the ranges 5-14.9, 15-29.9, and ≥ 30 was recorded in 14 (31%), 6 (13%), and 9 (20%) subjects, respectively. Mean distance covered in the 6-MWG walk test (6MWT) was 302 (± 19) m and 26 subjects (57%) showed exertional oxyhemoglobin desaturation. The median follow-up was about 18 months. Multivariate logistic regression analysis showed that exertional desaturation (HR 8.2; 1.8-36.5 95% CI; p = 0.006) and AHI ≥ 30, namely the threshold of severe OSA (HR 7.5; 1.8-30.6; p = 0.005), were the only independent variables related to progressive disease course.

CONCLUSION

We conclude that exertional desaturation and elevated AHI had independent negative prognostic significance in our ILD population.

Obstructive Sleep Apnea, Circadian Clock Disruption, and Metabolic Consequences

Obstructive sleep apnea (OSA) is a chronic disorder characterized by recurrent episodes of apnea and hypopnea during sleep. It is associated with various cardiovascular and metabolic complications, including type 2 diabetes mellitus (T2DM) and obesity. Many pathways can be responsible for T2DM development in OSA patients, e.g., those related to HIF-1 and SIRT1 expression. Moreover, epigenetic mechanisms, such as miRNA181a or miRNA199, are postulated to play a pivotal role in this link. It has been proven that OSA increases the occurrence of circadian clock disruption, which is also a risk factor for metabolic disease development. Circadian clock disruption impairs the metabolism of glucose, lipids, and the secretion of bile acids. Therefore, OSA-induced circadian clock disruption may be a potential, complex, underlying pathway involved in developing and exacerbating metabolic diseases among OSA patients. The current paper summarizes the available information pertaining to the relationship between OSA and circadian clock disruption in the context of potential mechanisms leading to metabolic disorders.