Idiopathic Pulmonary Fibrosis in United States Automated Claims. Incidence, Prevalence, and Algorithm Validation

Recent advances in TAM mechanisms in lung diseases

TYRO3, MERTK, and AXL receptor tyrosine kinases, collectively known as TAM receptors, play a vital role in maintaining lung tissue homeostasis by regulating integrity and self-renewal. These receptors activate signalling pathways that inhibit apoptosis, promote cell proliferation and differentiation, mediate cell adhesion and migration, and perform other essential biological functions. Additionally, TAM receptors are implicated in mechanisms that suppress anti-tumor immunity and confer resistance to immune checkpoint inhibitors. Disruption of the homeostatic balances can lead to pathological conditions such as lung inflammation, fibrosis, or tumors. Recent studies highlight their significant role in COVID-19-induced lung injury. However, the exact mechanisms by which TAM receptors contribute to lung diseases remain unclear. This article reviews the potential mechanisms of TAM receptor involvement in disease progression, focusing on lung inflammation, fibrosis, cancer, and COVID-19-induced lung injury. It also explores future research aspects and the therapeutic potentials of targeting TAM receptors, providing a theoretical foundation for understanding lung disease mechanisms and identifying treatment targets.

Comparative Analysis of Submaximal and Maximal Effort Capacities in Patients Post-COVID-19 and Individuals with Chronic Restrictive Lung Diseases

Whether impairments in submaximal and maximal effort capacities in individuals following acute COVID-19 infection resemble those found in patients with chronic pulmonary disease remains unclear. We aimed to analyze the submaximal and maximal effort capacities of patients after COVID-19 infection and those with alterations in lung mechanics similar to those observed in patients with chronic respiratory diseases. This retrospective cross-sectional observational study paired a group of post-COVID-19 individuals with another group of patients with chronic respiratory disease, using spirometric patterns similar to those observed post-COVID-19. Data from Spirometry, 6 min walk test (6-MWT), and cardiopulmonary exercise test (CPET) variables were compared, and correlations between spirometric variables and 6-WT/CPET were examined. The final sample comprised 20 patients, including 10 post-COVID-19 patients with a restrictive lung disease (RLD) pattern identified using spirometry and 10 patients with RLD. Both groups presented similar patterns of the analyzed variables, with significant correlations observed between forced vital capacity (FVC) the distance and speed achieved during the 6-MWT, and a negative correlation between FVC and V' E max. The degree of restriction in the overall sample influenced the covered distance and speed during the 6-MWT as well as the maximum minute ventilation during maximal effort.

Single Cell RNA-Seq Identifies Cell Subpopulations Contributing to Idiopathic Pulmonary Fibrosis in Humans

The cell populations, particularly subpopulations, involved in the onset and progression of idiopathic pulmonary fibrosis (IPF) remain incompletely understood. This study employed single-cell RNA-seq to identify cell populations and subpopulations with significantly altered proportions in the lungs of patients with IPF. In IPF lungs, endothelial cell proportions were significantly increased, while alveolar epithelial cell proportions were markedly decreased. Among the three identified fibroblast subpopulations, the proportion of myofibroblasts was significantly increased, while the proportions of the other two fibroblast subtypes were reduced. Similarly, within the three macrophage subpopulations, the macrophage_SPP1 subpopulation, localised to fibroblastic foci, showed a significant increase in proportion, while the alveolar macrophage subpopulation was significantly reduced. Trajectory analysis revealed that fibroblasts in IPF lungs could differentiate into myofibroblasts, and alveolar macrophages could transition into the macrophage_SPP1 subpopulation. Among T-cell subpopulations, only the CD4 T_FOXP3 subpopulation exhibited a significant change, whereas all four B-cell subpopulations showed significant proportional shifts. These findings provide a comprehensive view of the cellular alterations contributing to IPF pathogenesis. Extensive interactions among various cell populations and subpopulations were identified. The proportions of various cell populations and subpopulations in IPF lungs, including endothelial cells, fibroblasts, macrophages and B cells, were significantly altered. Further in-depth investigation into the roles of cell subpopulations with significantly altered proportions in the onset and progression of IPF will provide valuable insights into the pathological mechanisms underlying the disease. This understanding could facilitate the development of novel therapeutic strategies and medications for IPF treatment.

Blood Cell Counts and Inflammatory Indexes in Idiopathic Pulmonary Fibrosis

Introduction Inflammatory cells play a role in several idiopathic pulmonary fibrosis (IPF) pathogenesis steps. We aimed to evaluate the predictive value of peripheral blood cell (PBC) counts and inflammation indexes in the prognosis and mortality of IPF. Materials and methods A total of 155 patients with IPF followed between 1 January 2016 and 1 January 2023 were evaluated retrospectively. The baseline values and annual changes for pulmonary function tests and the PBC counts, ratios, and inflammation indexes (leukocyte, neutrophil, platelet, monocyte, lymphocyte, red cell distribution width (RDW), neutrophil-to-lymphocyte ratio (NLR), derived neutrophil-to-lymphocyte ratio (dNLR), platelet-to-lymphocyte ratio (PLR), monocyte-to-lymphocyte ratio (MLR), Systemic Immune Inflammation (SII) index, Systemic Inflammation Response Index (SIRI), the Aggregate Index of Systemic Inflammation (AISI)) were recorded. The relation between PBC, ratios, and inflammatory indexes with functional parameters (forced vital capacity (FVC), diffusing capacity of the lung for carbon monoxide (DLCO), 6-minute walking test (6MWT), Gender, Age, and Physiology (GAP) index, GAP stage) and mortality were examined. Results It was found that baseline RDW and neutrophil count were negatively correlated with survival time. The prognosis was worse in patients who had an RDW>13.6% and a neutrophil count>5.26×109/L (p = 0.0005 and p = 0.037, respectively). Significant correlations were observed between baseline peripheral blood cell counts, ratios, and index values (leukocyte, monocyte, neutrophil, platelet, monocyte, lymphocyte, NLR, PLR, MLR, SII, SIRI, AISI) and functional parameters (FVC, DLCO, 6MWT, GAP index, GAP stage). However, there was no significant correlation between the yearly changes. Conclusions Increased neutrophils and RDW may be related to the poor prognosis in IPF. Peripheral blood cell counts and inflammatory indices may provide useful information in identifying patients with worse functional status.

Identification of key mitochondria-related genes and their potential crosstalk role with immune pattern in Idiopathic pulmonary fibrosis

BACKGROUND

Idiopathic pulmonary fibrosis (IPF) stands out as a life-threatening and one of the most severe interstitial lung diseases. The pathogenesis of IPF is not fully understood, while recent studies have highlighted the association of mitochondrial dysfunction with IPF. This study is dedicated to pinpointing crucial genes related to mitochondria that potentially impact the advancement of IPF, thereby offering new perspectives on the pathogenesis of this condition.

METHODS

The Gene Expression Omnibus (GEO) database was utilized to download three datasets (GSE32537, GSE92592, and GSE150910), following which a comprehensive analysis was conducted to identify differentially expressed mitochondria-related genes (DEMTRGs) in the IPF lung tissues. Subsequently, GO and KEGG enrichment analysis of the DEMTRGs was performed. Next, external datasets and in vivo experiments were performed to validate their expression. Additionally, a Logistic regression model based on key DEMTRGs was constructed, and the model's ability to distinguish between IPF and controls was evaluated using the area under the receiver operating characteristic (ROC) curve (AUC). Finally, gene set enrichment analysis (GSEA) and CIBERSORT algorithm were conducted.

RESULTS

We identified five key DEMTRGs (ALDH18A1, ALDH1B1, MCCC1, ACAT1, and PDHA1), ALDH18A1 and ALDH1B1 exhibited upregulated expression levels, whereas MCCC1, ACAT1, and PDHA1 showed downregulation in the lung tissue of individuals with IPF. The expression levels of these key DEMTRGs were validated by an independent external dataset (GSE53845) and the bleomycin-induced pulmonary fibrosis mice. In addition, the ROCs indicated that the diagnostic model constructed based on key DEMTRGs could effectively distinguish between IPF and controls (AUC>0.8). GSEA analysis and immune-related analysis shed light on the potential mechanisms through which these key DEMTRGs influence IPF.

CONCLUSION

Our research has pinpointed key genes associated with mitochondria that may ultimately contribute to the progression of IPF by exerting regulatory effects on mitochondrial function, thereby influencing multiple cellular processes.

SPP1 induces idiopathic pulmonary fibrosis and NSCLC progression via the PI3K/Akt/mTOR pathway

BACKGROUND

The prevalence of non-small cell lung cancer (NSCLC) is notably elevated in individuals diagnosed with idiopathic pulmonary fibrosis (IPF). Secreted phosphoprotein 1 (SPP1), known for its involvement in diverse physiological processes, including oncogenesis and organ fibrosis, has an ambiguous role at the intersection of IPF and NSCLC. Our study sought to elucidate the function of SPP1 within the pathogenesis of IPF and its subsequent impact on NSCLC progression.

METHODS

Four GEO datasets was analyzed for common differential genes and TCGA database was used to analyze the prognosis. The immune infiltration was analyzed by TIMER database. SPP1 expression was examined in human lung tissues, the IPF fibroblasts and the BLM-induced mouse lung fibrosis model. Combined with SPP1 gene gain- and loss-of-function, qRT-PCR, Western blot, EdU and CCK-8 experiments were performed to evaluate the effects and mechanisms of SPP1 in IPF progression. Effect of SPP1 on NSCLC was detected by co-cultured IPF fibroblasts and NSCLC cells.

RESULTS

Through bioinformatics analysis, we observed a significant overexpression of SPP1 in both IPF and NSCLC patient datasets, correlating with enhanced immune infiltration of cancer-associated fibroblasts in NSCLC. Elevated levels of SPP1 were detected in lung tissue samples from IPF patients and bleomycin-induced mouse models, with partial colocalization observed with α-smooth muscle actin. Knockdown of SPP1 inhibits TGF-β1-induced differentiation of fibroblasts to myofibroblasts and the proliferation of IPF fibroblasts. Conversely, SPP1 overexpression promoted IPF fibroblast proliferation via PI3K/Akt/mTOR pathway. Furthermore, IPF fibroblasts promoted NSCLC cell proliferation and activated the PI3K/Akt/mTOR pathway; these effects were attenuated by SPP1 knockdown in IPF fibroblasts.

CONCLUSIONS

Our findings suggest that SPP1 functions as a molecule promoting both fibrosis and tumorigenesis, positioning it as a prospective therapeutic target for managing the co-occurrence of IPF and NSCLC.

Pulmonary Fibrosis Diagnosis and Disease Progression Detected Via Hair Metabolome Analysis

BACKGROUND

Fibrotic interstitial lung disease is often identified late due to non-specific symptoms, inadequate access to specialist care, and clinical unawareness precluding proper and timely treatment. Biopsy histological analysis is definitive but rarely performed due to its invasiveness. Diagnosis typically relies on high-resolution computed tomography, while disease progression is evaluated via frequent pulmonary function testing. This study tested the hypothesis that pulmonary fibrosis diagnosis and progression could be non-invasively and accurately evaluated from the hair metabolome, with the longer-term goal to minimize patient discomfort.

METHODS

Hair specimens collected from pulmonary fibrosis patients (n = 56) and healthy subjects (n = 14) were processed for metabolite extraction using 2DLC/MS-MS, and data were analyzed via machine learning. Metabolomic data were used to train machine learning classification models tuned via a rigorous combination of cross validation, feature selection, and testing with a hold-out dataset to evaluate classifications of diseased vs. healthy subjects and stable vs. progressed disease.

RESULTS

Prediction of pulmonary fibrosis vs. healthy achieved AUROCTRAIN = 0.888 (0.794-0.982) and AUROCTEST = 0.908, while prediction of stable vs. progressed disease achieved AUROCTRAIN = 0.833 (0.784 - 0.882) and AUROCTEST = 0. 799. Top metabolites for diagnosis included ornithine, 4-(methylnitrosamino)-1-3-pyridyl-N-oxide-1-butanol, Thr-Phe, desthiobiotin, and proline. Top metabolites for progression included azelaic acid, Thr-Phe, Ala-Tyr, indoleacetyl glutamic acid, and cytidine.

CONCLUSION

This study provides novel evidence that pulmonary fibrosis diagnosis and progression may in principle be evaluated from the hair metabolome. Longer term, this approach may facilitate non-invasive and accurate detection and monitoring of fibrotic lung diseases.

Identification of idiopathic pulmonary fibrosis hub genes and exploration of the mechanisms of action of Jinshui Huanxian formula

Idiopathic pulmonary fibrosis (IPF) is a common and heterogeneous chronic disease, and the mechanism of Jinshui Huanxian formula (JHF) on IPF remains unclear. For a total of 385 lung normal tissue samples from the Gene Expression Omnibus database, 37,777,639 gene pairs were identified through microarray and RNA-seq platforms. Using the individualized differentially expressed gene (DEG) analysis algorithm RankComp (FDR < 0.01), we identified 344 genes as DEGs in at least 95 % (n = 81) of the IPF samples. Of these genes, IGF1, IFNGR1, GLI2, HMGCR, DNM1, KIF4A, and TNFRSF11A were identified as hub genes. These genes were verified using quantitative reverse transcriptase polymerase chain reaction (qRT-PCR) in mice with pulmonary fibrosis (PF) and MRC-5 cells, and they were highly effective at classifying IPF samples in the independent dataset GSE134692 (AUC = 0.587-0.788) and mice with PF (AUC = 0.806-1.000). Moreover, JHF ameliorated the pathological changes in mice with PF and significantly reversed the changes in hub gene expression (KIF4A, IFNGR1, and HMGCR). In conclusion, a series of IPF hub genes was identified, and validated in an independent dataset, mice with PF, and MRC-5 cells. Moreover, the abnormal gene expression was normalized by JHF. These findings provide guidance for further exploration of the pathogenesis and treatment of IPF.

Lactate transport inhibition therapeutically reprograms fibroblast metabolism in experimental pulmonary fibrosis

Myofibroblast differentiation, essential for driving extracellular matrix synthesis in pulmonary fibrosis, requires increased glycolysis. While glycolytic cells must export lactate, the contributions of lactate transporters to myofibroblast differentiation are unknown. In this study, we investigated how MCT1 and MCT4, key lactate transporters, influence myofibroblast differentiation and experimental pulmonary fibrosis. Our findings reveal that inhibiting MCT1 or MCT4 reduces TGFβ-stimulated pulmonary myofibroblast differentiation in vitro and decreases bleomycin-induced pulmonary fibrosis in vivo. Through comprehensive metabolic analyses, including bioenergetics, stable isotope tracing, metabolomics, and imaging mass spectrometry in both cells and mice, we demonstrate that inhibiting lactate transport enhances oxidative phosphorylation, reduces reactive oxygen species production, and diminishes glucose metabolite incorporation into fibrotic lung regions. Furthermore, we introduce VB253, a novel MCT4 inhibitor, which ameliorates pulmonary fibrosis in both young and aged mice, with comparable efficacy to established antifibrotic therapies. These results underscore the necessity of lactate transport for myofibroblast differentiation, identify MCT1 and MCT4 as promising pharmacologic targets in pulmonary fibrosis, and support further evaluation of lactate transport inhibitors for patients for whom limited therapeutic options currently exist.

Association between Antacid Exposure and Risk of Interstitial Lung Diseases

BACKGROUND

The mechanisms leading to lung fibrosis are still under investigation. This study aimed to demonstrate whether antacids could prevent the development of interstitial lung disease (ILD).

METHODS

This population-based longitudinal cohort study was conducted between January 2006 and December 2010 in South Korea. Eligible subjects were ≥40 years of age, exposed to proton pump inhibitors (PPI)±histamine-2 receptor antagonists (H-2 blockers) or H-2 blockers only, and had no history of ILD between 2004 and 2005. Exposure to antacids was defined as the administration of either PPI or H-2 receptor antagonists for >14 days, whereas underexposure was defined as antacid treatment administered for less than 14 days. Newly developed ILDs, including idiopathic pulmonary fibrosis (IPF), were counted during the 5-year observation period. The association between antacid exposure and ILD development was evaluated using adjusted Cox regression models with variables, such as age, sex, smoking history, and comorbidities.

RESULTS

The incidence rates of ILD with/without antacid use were 43.2 and 33.8/100,000 person-years, respectively and those of IPF were 14.9 and 22.9/100,000 person-years, respectively. In multivariable analysis, exposure to antacid before the diagnosis of ILD was independently associated with a reduced development of ILD (hazard ratio [HR], 0.57; 95% confidence interval [CI], 0.45 to 0.71; p<0.001), while antacid exposure was not associated with development of IPF (HR, 0.88; 95% CI, 0.72 to 1.09; p=0.06).

CONCLUSION

Antacid exposure may be independently associated with a decreased risk of ILD development.

The Impact of Chronic Comorbidities on Outcomes in Acute Exacerbations of Idiopathic Pulmonary Fibrosis

INTRODUCTION

Idiopathic pulmonary fibrosis is a chronic progressive lung disease of unknown cause with a high associated mortality. We aimed to compare the impact of chronic medical conditions on hospital outcomes of patients with acute exacerbations of idiopathic pulmonary fibrosis (AE-IPF).

METHODS

This was a retrospective cohort study using the NIS database from 2016 to 2018. We included patients aged 60 and older hospitalized in academic medical centers with the diagnoses of IPF and acute respiratory failure. We examined factors associated with hospital mortality and length of stay (LOS) using survey-weighted multivariate logistic and negative binomial regression.

RESULTS

Out of 4975 patients with AE-IPF, 665 (13.4%) did not survive hospitalization. There was no difference in the mean age between survivors and non-survivors. Patients were more likely to be male, predominantly white, and have Medicare coverage. Most non-survivors were from households with higher median income. Hospital LOS was longer among non-survivors than survivors (9.4 days vs. 9.8 days; p < 0.001). After multivariate-logistic regression, diabetes was found to be protective (aOR 0.62, 95% CI 0.50-0.77; p < 0.0001) while chronic kidney disease (CKD) conferred a significantly higher risk of death after AE-IPF (aOR 6.85, 95% CI 1.90-24.7; p = 0.00). Our multivariate adjusted negative binomial regression model for LOS identified obesity (IRR 0.85, 95% CI 0.76-0.94; p ≤ 0.00) and hypothyroidism (IRR 0.90, 95% CI 0.83-0.98; p = 0.02) to be associated with shorter hospital LOS.

CONCLUSIONS

Our results suggest that CKD is a significant contributor to hospital mortality in AE-IPF, and diabetes mellitus may be protective. Obesity and hypothyroidism are linked with shorter hospital LOS among patients hospitalized with AE-IPF in US academic medical centers.

A Review: The Potential Involvement of Growth Arrest-Specific 6 and Its Receptors in the Pathogenesis of Lung Damage and in Coronavirus Disease 2019

The tyrosine kinase receptors of the TAM family-Tyro3, Axl and Mer-and their main ligand Gas6 (growth arrest-specific 6) have been implicated in several human diseases, having a particularly important role in the regulation of innate immunity and inflammatory response. The Gas6/TAM system is involved in the recognition of apoptotic debris by immune cells and this mechanism has been exploited by viruses for cell entry and infection. Coronavirus disease 2019 (COVID-19) is a multi-systemic disease, but the lungs are particularly affected during the acute phase and some patients may suffer persistent lung damage. Among the manifestations of the disease, fibrotic abnormalities have been observed among the survivors of COVID-19. The mechanisms of COVID-related fibrosis remain elusive, even though some parallels may be drawn with other fibrotic diseases, such as idiopathic pulmonary fibrosis. Due to the still limited number of scientific studies addressing this question, in this review we aimed to integrate the current knowledge of the Gas6/TAM axis with the pathophysiological mechanisms underlying COVID-19, with emphasis on the development of a fibrotic phenotype.

Pleuropulmonary Manifestations of Vacuoles, E1 Enzyme, X-Linked, Autoinflammatory, Somatic (VEXAS) Syndrome

BACKGROUND

The vacuoles, E1 enzyme, X-linked, autoinflammatory, somatic (VEXAS) syndrome is a newly identified autoinflammatory disorder related to somatic UBA1 mutations. Up to 72% of patients may show lung involvement.

RESEARCH QUESTION

What are the pleuropulmonary manifestations in VEXAS syndrome?

STUDY DESIGN AND METHODS

One hundred fourteen patients were included in the French cohort of VEXAS syndrome between November 2020 and May 2021. Each patient included in the study who had an available chest CT scan was discussed in an adjudication multidisciplinary team and classified as showing potentially pleuropulmonary-specific involvement of VEXAS syndrome or others.

RESULTS

Fifty-one patients had a CT scan available for review and 45 patients (39%) showed pleuropulmonary abnormalities on chest CT scan that were considered related to VEXAS syndrome after adjudication. Most patients were men (95%) with a median age 67.0 years at the onset of symptoms. Among these 45 patients, 44% reported dyspnea and 40% reported cough. All 45 patients showed lung opacities on chest CT scan (including ground-glass opacities [87%], consolidations [49%], reticulation [38%], and septal lines [51%]) and 53% of patients showed pleural effusion. Most patients showed improvement with prednisone, but usually required > 20 mg/d. The main clinical and biological features as well the median survival did not differ between the 45 patients with pleuropulmonary involvement and the rest of the cohort, suggesting that the prevalence of pleuropulmonary involvement might have been underdiagnosed in the rest of the cohort.

INTERPRETATION

Pulmonary manifestations are frequent in VEXAS syndrome, but rarely are at the forefront. The initial outcome is favorable with prednisone and does not seem to lead to pulmonary fibrosis.

Epidemiology and comorbidities in idiopathic pulmonary fibrosis: a nationwide cohort study

BACKGROUND

Idiopathic pulmonary fibrosis (IPF) is frequently accompanied by comorbidities, with the management of these comorbidities crucial for clinical outcomes. This study investigated the prevalence, incidence, changes over time, and clinical impact of comorbidities in IPF patients, based on nationwide claims data in South Korea.

METHODS

This retrospective cohort study utilised nationwide health claim data in South Korea between 2011 and 2019. Patients with IPF were defined as those with ICD-10 code J84.1 and Rare Intractable Disease code V236 who made at least one claim per year. Patients were classified by sex, age, pirfenidone use and burden of comorbidities, and differences among groups were determined.

RESULTS

The yearly prevalence rate of IPF increased from 7.50 to 23.20 per 100,000 people, and the yearly incidence rate increased from 3.56 to 7.91 per 100,000 person-years over time. The most common respiratory comorbidity was chronic obstructive pulmonary disease (37.34%), followed by lung cancer (3.34%), whereas the most common non-respiratory comorbidities were gastro-oesophageal reflux disease (70.83%), dyslipidaemia (62.93%) and hypertension (59.04%). The proportion of some comorbidities differed by sex, age and use of pirfenidone. The proportion of lung cancer was higher in patients treated with pirfenidone, whereas the proportion of anxiety and depression were lower in patients not treated with pirfenidone. Charlson comorbidity index ≥ 4 was associated with increases in hospitalisations and total medical costs.

CONCLUSIONS

The yearly prevalence and incidence of IPF and comorbidities in Korea increased over time. These comorbidities affected the use of pirfenidone and medical resources.

Exploring the comorbidity mechanisms between asthma and idiopathic pulmonary fibrosis and the pharmacological mechanisms of Bu-Shen-Yi-Qi decoction therapy via network pharmacology

Backgrounds

Asthma and idiopathic pulmonary fibrosis (IPF) are common chronic diseases of the respiratory system in clinical practice. However, the relationship and molecular links remain unclear, and the current treatment’s efficacy is disappointing. Bu-Shen-Yi-Qi (BSYQ) decoction has proven effective in treating various chronic airway inflammatory diseases, including asthma and IPF. But the underlying pharmacological mechanisms are still to be elucidated.

Methods

This study searched the proteins related to asthma and IPF via TTD, CTD, and DisGeNET databases and then submitted to the STRING to establish the protein–protein interaction (PPI) network. The co-bioinformatics analysis was conducted by Metascape. The active ingredients of BSYQ decoction were screened from TCMSP, ETCM, BATMAN-TCM databases, and HPLC/MS experiment. The corresponding targets were predicted based on TCMSP, ETCM, and BATMAN-TCM databases. The shared targets for asthma and IPF treatment were recognized, and further GO and KEGG analyses were conducted with the DAVID platform. Finally, molecule docking via Autodock Vina was employed to predict the potential binding mode between core potential compounds and targets.

Results

Finally, 1333 asthma-related targets and 404 IPF-related proteins were retrieved, 120 were overlapped between them, and many of the asthma-related proteins fall into the same statistically significant GO terms with IPF. Moreover, 116 active ingredients of BSYQ decoction were acquired, and 1535 corresponding targets were retrieved. Eighty-three potential compounds and 56 potential targets were recognized for both asthma and IPF treatment. GO and KEGG analysis indicated that the inflammation response, cytokine production, leukocyte differentiation, oxygen level response, etc., were the common pathological processes in asthma and IPF, which were regulated by BSYQ decoction. Molecule docking further predicted the potential binding modes between the core potential compounds and targets.

Conclusion

The current study successfully clarified the complex molecule links between asthma and IPF and found the potential common targets. Then we demonstrated the efficacy of BSYQ decoction for asthma and IPF treatment from the angle of network pharmacology, which may provide valuable references for further studies and clinical use.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12906-022-03637-7.

Idiopathic Pulmonary Fibrosis and Telomeres

Idiopathic pulmonary fibrosis is an interstitial lung disease of unknown etiology with a highly compromised prognosis and a significant mortality rate within a few years of diagnosis. Despite being idiopathic, it has been shown that telomeric shortening could play an important role in its etiopathogenesis. Mutations in telomere-related genes have been identified, but they are not always present despite telomere shortening. On the other hand, this telomeric shortening has been linked to a worse prognosis of the disease independently of other clinical factors, implying it may serve as a biomarker.

Screening for idiopathic pulmonary fibrosis using comorbidity signatures in electronic health records

Idiopathic pulmonary fibrosis (IPF) is a lethal fibrosing interstitial lung disease with a mean survival time of less than 5 years. Nonspecific presentation, a lack of effective early screening tools, unclear pathobiology of early-stage IPF and the need for invasive and expensive procedures for diagnostic confirmation hinder early diagnosis. In this study, we introduce a new screening tool for IPF in primary care settings that requires no new laboratory tests and does not require recognition of early symptoms. Using subtle comorbidity signatures identified from the history of medical encounters of individuals, we developed an algorithm, called the zero-burden comorbidity risk score for IPF (ZCoR-IPF), to predict the future risk of an IPF diagnosis. ZCoR-IPF was trained on a national insurance claims database and validated on three independent databases, comprising a total of 2,983,215 participants, with 54,247 positive cases. The algorithm achieved positive likelihood ratios greater than 30 at a specificity of 0.99 across different cohorts, for both sexes, and for participants with different risk states and history of confounding diseases. The area under the receiver-operating characteristic curve for ZCoR-IPF in predicting IPF exceeded 0.88 and was approximately 0.84 at 1 and 4 years before a conventional diagnosis, respectively. Thus, if adopted, ZCoR-IPF can potentially enable earlier diagnosis of IPF and improve outcomes of disease-modifying therapies and other interventions.

Agent Orange Exposure and Risk of Idiopathic Pulmonary Fibrosis among U.S. Veterans

Rationale: There is limited literature exploring the relationship between military exposures and idiopathic pulmonary fibrosis (IPF). Objectives: To evaluate whether exposure to Agent Orange is associated with an increased risk of IPF among veterans. Methods: We used Veterans Health Administration data to identify patients diagnosed with IPF between 2010 and 2019. We restricted the cohort to male Vietnam veterans and performed multivariate logistic regression to examine the association between presumptive Agent Orange exposure and IPF. We conducted sensitivity analyses restricting the cohort to army veterans (highest theoretical burden of exposure, surrogate for dose response) and a more specific case definition of IPF. Fine-Gray competing risk models were used to evaluate age to IPF diagnosis. Measurements and Main Results: Among 3.6 million male Vietnam veterans, 948,103 (26%) had presumptive Agent Orange exposure. IPF occurred in 2.2% of veterans with Agent Orange exposure versus 1.9% without exposure (odds ratio, 1.14; 95% confidence interval [CI], 1.12-1.16; P < 0.001). The relationship persisted after adjusting for known IPF risk factors (odds ratio, 1.08; 95% CI, 1.06-1.10; P < 0.001). The attributable risk among exposed veterans was 7% (95% CI, 5.3-8.7%; P < 0.001). Numerically greater risk was observed when restricting the cohort to 1) Vietnam veterans who served in the army and 2) a more specific definition of IPF. After accounting for the competing risk of death, veterans with Agent Orange exposure were still more likely to develop IPF. Conclusions: Presumptive Agent Orange exposure is associated with greater risk of IPF. Future research should validate this association and investigate the biological mechanisms involved.

A novel gene signature based on the hub genes of COVID-19 predicts the prognosis of idiopathic pulmonary fibrosis

Background: Increasing evidence has demonstrated that there was a strong correlation between COVID-19 and idiopathic pulmonary fibrosis (IPF). However, the studies are limited, and the real biological mechanisms behind the IPF progression were still uncleared.

Methods: GSE70866 and GSE 157103 datasets were downloaded. The weight gene co-expression network analysis (WGCNA) algorithms were conducted to identify the most correlated gene module with COVID-19. Then the genes were extracted to construct a risk signature in IPF patients by performing Univariate and Lasso Cox Regression analysis. Univariate and Multivariate Cox Regression analyses were used to identify the independent value for predicting the prognosis of IPF patients. What’s more, the Kyoto Encyclopedia of Genes and Genomes (KEGG), Gene Ontology (GO), and gene set enrichment analysis (GSEA) were conducted to unveil the potential biological pathways. CIBERSORT algorithms were performed to calculate the correlation between the risk score and immune cells infiltrating levels.

Results: Two hundred thirty three differentially expressed genes were calculated as the hub genes in COVID-19. Fourteen of these genes were identified as the prognostic differentially expressed genes in IPF. Three (MET, UCHL1, and IGF1) of the fourteen genes were chosen to construct the risk signature. The risk signature can greatly predict the prognosis of high-risk and low-risk groups based on the calculated risk score. The functional pathway enrichment analysis and immune infiltrating analysis showed that the risk signature may regulate the immune-related pathways and immune cells.

Conclusion: We identified prognostic differentially expressed hub genes related to COVID-19 in IPF. A risk signature was constructed based on those genes and showed great value for predicting the prognosis in IPF patients. What’s more, three genes in the risk signature may be clinically valuable as potential targets for treating IPF patients and IPF patients with COVID-19.

Comparing outcomes of ILD patients managed in specialised versus non-specialised centres

Background

Early appropriate diagnosis and treatment of interstitial lung diseases (ILD) is crucial to slow disease progression and improve survival. Yet it is unknown whether initial management in an expert centre is associated with improved outcomes. Therefore, we assessed mortality, hospitalisations and health care costs of ILD patients initially diagnosed and managed in specialised ILD centres versus non-specialised centres and explored differences in pharmaceutical treatment patterns.

Methods

An epidemiological claims data analysis was performed, including patients with different ILD subtypes in Germany between 2013 and 2018. Classification of specialised centres was based on the number of ILD patients managed and procedures performed, as defined by the European Network on Rare Lung Diseases. Inverse probability of treatment weighting was used to adjust for covariates. Mortality and hospitalisations were examined via weighted Cox models, cost differences by weighted gamma regression models and differences in treatment patterns with weighted logistic regressions.

Results

We compared 2022 patients managed in seven specialised ILD centres with 28,771 patients managed in 1156 non-specialised centres. Specialised ILD centre management was associated with lower mortality (HR: 0.87, 95% CI 0.78; 0.96), lower all-cause hospitalisation (HR: 0.93, 95% CI 0.87; 0.98) and higher respiratory-related costs (€669, 95% CI €219; €1156). Although risk of respiratory-related hospitalisations (HR: 1.00, 95% CI 0.92; 1.10) and overall costs (€− 872, 95% CI €− 75; €1817) did not differ significantly, differences in treatment patterns were observed.

Conclusion

Initial management in specialised ILD centres is associated with improved mortality and lower all-cause hospitalisations, potentially due to more differentiated diagnostic approaches linked with more appropriate ILD subtype-adjusted therapy.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12931-022-02143-1.

Impact of gastroesophageal reflux disease on idiopathic pulmonary fibrosis and lung transplant recipients

PURPOSE OF REVIEW

Idiopathic pulmonary fibrosis (IPF) is a prevalent subset of interstitial lung disease (ILD) that often progresses to require lung transplantation. Gastroesophageal reflux disease (GERD) is common in the IPF population, and GER-related micro-aspiration appears to be an important risk factor for IPF pathogenesis and for the deterioration of transplanted lung function.

RECENT FINDINGS

Many patients with IPF have elevated esophageal acid exposure on reflux testing despite having no or minimal symptoms. Studies on the effects of medical GERD therapy on IPF-related outcomes have had mixed results. Antireflux surgery is safe in appropriately selected IPF patients, and appears to have potential for slowing the decline of lung function. GERD can persist, improve or develop after lung transplantation, and the presence of GERD is associated with allograft injury and pulmonary function decline in lung transplant recipients.

SUMMARY

Clinicians should have a low threshold to assess for objective evidence of GERD in IPF patients. Antireflux surgery in IPF patients with GERD appears to improve lung function, but further studies are needed before surgical treatment can be recommended routinely in this setting. In lung transplant recipients, reflux testing after transplant is the most accurate way to guide GERD treatment decisions.

Targeting fibrosis, mechanisms and cilinical trials

Fibrosis is characterized by the excessive extracellular matrix deposition due to dysregulated wound and connective tissue repair response. Multiple organs can develop fibrosis, including the liver, kidney, heart, and lung. Fibrosis such as liver cirrhosis, idiopathic pulmonary fibrosis, and cystic fibrosis caused substantial disease burden. Persistent abnormal activation of myofibroblasts mediated by various signals, such as transforming growth factor, platelet-derived growth factor, and fibroblast growh factor, has been recongized as a major event in the occurrence and progression of fibrosis. Although the mechanisms driving organ-specific fibrosis have not been fully elucidated, drugs targeting these identified aberrant signals have achieved potent anti-fibrotic efficacy in clinical trials. In this review, we briefly introduce the aetiology and epidemiology of several fibrosis diseases, including liver fibrosis, kidney fibrosis, cardiac fibrosis, and pulmonary fibrosis. Then, we summarise the abnormal cells (epithelial cells, endothelial cells, immune cells, and fibroblasts) and their interactions in fibrosis. In addition, we also focus on the aberrant signaling pathways and therapeutic targets that regulate myofibroblast activation, extracellular matrix cross-linking, metabolism, and inflammation in fibrosis. Finally, we discuss the anti-fibrotic drugs based on their targets and clinical trials. This review provides reference for further research on fibrosis mechanism, drug development, and clinical trials.

Caveolin-1 peptide regulates p53-microRNA-34a feedback in fibrotic lung fibroblasts

Idiopathic pulmonary fibrosis (IPF) is a life-threatening disease resulting from dysregulated repair responses to lung injury. Excessive extracellular matrix deposition by expanding myofibroblasts and fibrotic lung fibroblasts (fLfs) has been implicated in the pathogenesis of PF, including IPF. We explored fLfs' microRNA-34a (miR-34a) expression from IPF tissues. Basal miR-34a levels were decreased with reduced binding of p53 to the promoter DNA and 3'UTR mRNA sequences. Overexpression of miR-34a in fLfs increased p53, PAI-1, and reduced pro-fibrogenic markers. The regulatory effects of miR-34a were altered by modifying the p53 expression. Precursor-miR-34a lung transduction reduced bleomycin-induced PF in wild-type mice. fLfs treated with caveolin-1 scaffolding domain peptide (CSP) or its fragment, CSP7, restored miR-34a, p53, and PAI-1. CSP/CSP7 reduced PDGFR-β and pro-fibrogenic markers, which was abolished in fLfs following blockade of miR-34a expression. These peptides failed to resolve PF in mice lacking miR-34a in fLfs, indicating miR-34a-p53-feedback induction required for anti-fibrotic effects.

Clinical Overview of Progressive Fibrotic Interstitial Lung Disease

Interstitial lung diseases (ILD) on the whole have variable prognoses, but there are those which manifest with fibrosis and are characterized by disease progression. Chief among these is idiopathic pulmonary fibrosis, but other ILDs, including autoimmune ILD and chronic hypersensitivity pneumonitis, may have a progressive fibrotic phenotype also. A usual interstitial pneumonia pattern of lung involvement is a prominent risk factor for such a course, suggesting shared fibrotic pathways that may be targeted by antifibrotic therapies. This brief review describes ILDs that are most commonly fibrotic, shared risk factors for development of PF-ILD, and evidence for antifibrotic use in their management.

Management of BMI Is a Potential New Approach for the Prevention of Idiopathic Pulmonary Fibrosis

Aims: Current idiopathic pulmonary fibrosis (IPF) therapies usually show a poor outcome or treatment efficacy. The search for new risk factors has significant implications in preventing, delaying, and treating IPF. The association between obesity and the risk of IPF is not clear. This study aimed to investigate the role of different obesity types in IPF risk, which provides the possibility of weight loss as a new approach for IPF prevention.

Methods: We conducted a two-sample Mendelian randomization (MR) analysis to assess the causal effect of obesity on IPF risk. We collected summary data of genetically determined obesity-related traits, including body mass index (BMI), waist circumference (WC), and waist-to-hip ratio (WHR) from large-scale consortia (the sample size ranging from 232,101 to 681,275), and genetic association with IPF from one of the largest meta-analyses including 2,668 cases. A total of 35–469 single nucleotide polymorphisms were selected as instrumental variables for obesity-related traits. We further performed multivariable MR to estimate the independent effect of BMI and WC on the risk of IPF.

Results: Increased BMI and WC were associated with higher risk of IPF [odds ratio (OR) = 1.51, 95% confidence interval (CI) (1.22–1.87), p = 1.27 × 10^–4, and OR = 1.71, 95% CI (1.08–2.72), p = 2.33 × 10^–2, respectively]. Similar results for the BMI and WC were obtained in the replicated analysis. Subsequently, only the result for BMI survived following the multiple testing correction and showed good consistency with the weighted median estimator. Sensitivity analyses indicated that there was no heterogeneity or horizontal pleiotropy for MR estimations. Further multivariable MR suggested that the BMI showed the same direction and similar magnitude with that in the univariable MR analysis. There was little evidence to support the causal role of WHR on the risk of IPF in this study.

Conclusion: Genetically determined BMI demonstrates a causal risk for IPF, which offers a novel insight into probing potential mechanisms. Meanwhile, these results also suggest that weight loss may be beneficial to IPF prevention.

Epidemiology of Idiopathic Pulmonary Fibrosis among U.S. Veterans, 2010-2019

Rationale: The development of novel therapies for idiopathic pulmonary fibrosis (IPF) has brought increased attention to the population burden of disease. However, little is known about the epidemiology of IPF among U.S. Veterans. Objectives: This study examines temporal trends in incidence and prevalence, patient characteristics, and risk factors associated with IPF among a national cohort of U.S. Veterans. Methods: We used data from the Veterans Health Administration (VHA) electronic health record system to describe the incidence, prevalence, and geographic distribution of IPF between January 1, 2010, and December 31, 2019. We evaluated patient characteristics associated with IPF using multivariate logistic regression. Results: Among 10.7 million Veterans who received care from the VHA between 2010 and 2019, 139,116 (1.26%) were diagnosed with IPF. Using a narrow case definition of IPF, the prevalence increased from 276 cases per 100,000 in 2010 to 725 cases per 100,000 in 2019. The annual incidence increased from 73 cases per 100,000 person-years in 2010 to 210 cases per 100,000 person-years in 2019. Higher absolute incidence and prevalence rates were noted when a broader case definition of IPF was used. Risk factors associated with IPF among Veterans included older age, White race, tobacco use, and rural residence. After accounting for interactions, the average marginal difference in IPF prevalence between males and females was small. There was significant geographic heterogeneity of disease across the United States. Conclusions: This study is the first comprehensive epidemiologic analysis of IPF among the U.S. Veteran population. The incidence and prevalence of IPF among Veterans has increased over the past decade. The effect of sex on risk of IPF was attenuated once accounting for other risk factors. The geographic distribution of disease is heterogeneous across the United States with rural residence associated with higher odds of IPF. The reasons for these trends deserve further study.

Targeting PI3K/AKT signaling for treatment of idiopathic pulmonary fibrosis

Idiopathic pulmonary fibrosis (IPF) is a chronic progressive fibrotic interstitial pneumonia with unknown causes. The incidence rate increases year by year and the prognosis is poor without cure. Recently, phosphatidylinositol 3-kinase (PI3K)/protein kinase B (PKB/AKT) signaling pathway can be considered as a master regulator for IPF. The contribution of the PI3K/AKT in fibrotic processes is increasingly prominent, with PI3K/AKT inhibitors currently under clinical evaluation in IPF. Therefore, PI3K/AKT represents a critical signaling node during fibrogenesis with potential implications for the development of novel anti-fibrotic strategies. This review epitomizes the progress that is being made in understanding the complex interpretation of the cause of IPF, and demonstrates that PI3K/AKT can directly participate to the greatest extent in the formation of IPF or cooperate with other pathways to promote the development of fibrosis. We further summarize promising PI3K/AKT inhibitors with IPF treatment benefits, including inhibitors in clinical trials and pre-clinical studies and natural products, and discuss how these inhibitors mitigate fibrotic progression to explore possible potential agents, which will help to develop effective treatment strategies for IPF in the near future.

Interstitial lung abnormalities - current knowledge and future directions

Efforts to grasp the significance of radiologic changes similar to interstitial lung disease (ILD) in undiagnosed individuals have intensified in the recent decade. The term interstitial lung abnormalities (ILA) is an emerging definition of such changes, defined by visual examination of computed tomography scans. Substantial insights have been made in the origins and clinical consequences of these changes, as well as automated measures of early lung fibrosis, which will likely lead to increased recognition of early fibrotic lung changes among clinicians and researchers alike.

Interstitial lung abnormalities have an estimated prevalence of 7–10% in elderly populations. They correlate with many ILD risk factors, both epidemiologic and genetic. Additionally, histopathological similarities with IPF exist in those with ILA. While no established blood biomarker of ILA exists, several have been suggested. Distinct imaging patterns indicating advanced fibrosis correlate with worse clinical outcomes. ILA are also linked with adverse clinical outcomes such as increased mortality and risk of lung cancer.

Progression of ILA has been noted in a significant portion of those with ILA and is associated with many of the same features as ILD, including advanced fibrosis. Those with ILA progression are at risk of accelerated FVC decline and increased mortality. Radiologic changes resembling ILD have also been attained by automated measures. Such measures associate with some, but not all the same factors as ILA.

ILA and similar radiologic changes are in many ways analogous to ILD and likely represent a precursor of ILD in some cases. While warranting an evaluation for ILD, they are associated with poor clinical outcomes beyond possible ILD development and thus are by themselves a significant finding. Among the present objectives of this field are the stratification of patients with regards to progression and the discovery of biomarkers with predictive value for clinical outcomes.

The natural history of idiopathic pulmonary fibrosis in a large European population: the role of age, sex and comorbidities

Placebo arms of clinical trials provide an opportunity to investigate the natural history of idiopathic pulmonary fibrosis (IPF) but these patients are not representative of the real life IPF population. Objective of this article is to evaluate patients' characteristics of incident IPF cases and their impact on mortality and hospitalizations risk. We conducted a retrospective cohort study using data from administrative databases from 2000 to 2010. Based on different algorithms reported in literature, incident IPF cases were identified. We applied Cox proportional hazards models to assess relationship between patients' characteristics, mortality and hospitalization. According to three case definitions, we identified 2338, 460 and 1704 incident IPF cases. Mean age at diagnosis was about 72 years, the proportion of male varied between 59 and 62% and patients with at least one chronic disease were between 70 and 74%. Age, male sex and comorbidities were associated to worse outcomes. Congestive heart failure (CHF), diabetes and cancer were conditions associated to mortality, while those associated to hospitalization were CHF and chronic obstructive pulmonary disease. Our data source provided one of the largest samples of unselected patients with a long follow-up period. Using different algorithms proposed and validated in literature, we observed that mortality and hospitalization rate are high in patients with IPF and age, sex and comorbidities significantly affect clinical outcomes. Females show a significant survival advantage over males, even after adjusting for age and comorbidities. Patients with pre-existing diseases, especially those with pulmonary and cardiovascular diseases are at higher risk.

Sex Differences in the Incidence and Outcomes of Patients Hospitalized by Idiopathic Pulmonary Fibrosis (IPF) in Spain from 2016 to 2019

(1) Background: To assess sex differences in the incidence, characteristics, procedures and outcomes of patients admitted with idiopathic pulmonary fibrosis (IPF); and to analyze variables associated with in-hospital mortality (IHM). (2) Methods: We analyzed data collected by the Spanish National Hospital Discharge Database, 2016-2019. (3) Results: We identified 13,278 hospital discharges (66.4% men) of IPF (primary diagnosis 32.33%; secondary diagnosis: 67.67%). Regardless of the diagnosis position, IPF incidence was higher among men than women, increasing with age. Men had 2.74 times higher IPF incidence than women. Comorbidity was higher for men in either primary or secondary diagnosis. After matching, men had higher prevalence of pulmonary embolism and pneumonia, and women of congestive heart failure, dementia, rheumatoid disease and pulmonary hypertension. Invasive ventilation, bronchoscopy and lung transplantation were received more often by men than women. IHM was higher among men with IPF as primary diagnosis than among women and increased with age in both sexes and among those who suffered cancer, pneumonia or required mechanical ventilation. (4) Conclusions: Incidence of IPF was higher among men than women, as well as comorbidity and use of bronchoscopy, ventilation and lung transplantation. IHM was worse among men than women with IPF as primary diagnosis, increasing with age, cancer, pneumonia or mechanical ventilation use.

Global incidence and prevalence of idiopathic pulmonary fibrosis

BACKGROUND

Idiopathic pulmonary fibrosis (IPF) is a progressive debilitating lung disease with considerable morbidity. Heterogeneity in epidemiologic studies means the full impact of the disease is unclear.

METHODS

A targeted literature search for population-based, observational studies reporting incidence and/or prevalence of IPF from January 2009 to April 2020 was conducted. Identified studies were aggregated by country. For countries with multiple publications, a weighted average was determined. Incidence and prevalence data were adjusted for between-study differences where possible. The final model included adjusted estimates of incidence and prevalence per 10,000 of the population with 95% confidence intervals. As prevalence estimates vary depending on the definitions used, estimates were based on a specific case definition of IPF.

RESULTS

Overall, 22 studies covering 12 countries met the inclusion criteria, with 15 reporting incidence and 18 reporting prevalence estimates. The adjusted incidence estimates (per 10,000 of the population) ranged from 0.35 to 1.30 in Asia-Pacific countries, 0.09 to 0.49 in Europe, and 0.75 to 0.93 in North America. Unadjusted and adjusted incidence estimates were consistent. The adjusted prevalence estimates ranged from 0.57 to 4.51 in Asia-Pacific countries, 0.33 to 2.51 in Europe, and 2.40 to 2.98 in North America. South Korea had the highest incidence and prevalence estimates. When prevalence estimates were compared to country-specific rare disease thresholds, IPF met the definition of a rare disease in all countries except South Korea. There were notable geographic gaps for IPF epidemiologic data.

CONCLUSIONS

Due to differences in study methodologies, there is worldwide variability in the reported incidence and prevalence of IPF. Based on the countries included in our analysis, we estimated the adjusted incidence and prevalence of IPF to be in the range of 0.09-1.30 and 0.33-4.51 per 10,000 persons, respectively. According to these prevalence estimates, IPF remains a rare disease. For consistency, future epidemiologic studies of IPF should take age, sex, smoking status, and the specificity of case definitions into consideration.

Idiopathic pulmonary fibrosis: Current knowledge, future perspectives and its importance in radiation oncology

Idiopathic pulmonary fibrosis (IPF) is a progressive, fibrotic lung disease with an unknown cause. Uncertainties still remain regarding the pathogenesis of IPF, and the prognosis of this disease is poor despite some recent improvements in treatment. Radiation induced lung injury (RILI) is a common complication and a dose-limiting toxicity of thoracic radiotherapy. Importantly, IPF is a crucial risk factor for pulmonary toxicity after thoracic radiotherapy. Although IPF is not universally accepted as a definite contraindication for thoracic radiotherapy at present, it has been shown that IPF can increase the risk of severe and fatal complications after thoracic radiotherapy. Proton beam therapy has shown promising results in reducing the incidence of thoracic radiotherapy related life-threatening complications in IPF patients, but the current evidence is not sufficient to recommend the standard use of it. Many similarities are noticeable between IPF and RILI in terms of pathogenesis and underlying mechanisms. Better understanding of the mechanisms of IPF and RILI may enable clinicians to provide safer and more effective thoracic radiotherapy treatments in cancer patients with IPF. In this review, we summarize the current knowledge of IPF, present the importance of IPF in radiation oncology practice, and highlight the similarities and relationship between IPF and RILI.

A population-based observational study of patients with pulmonary disorders in intensive care unit

BACKGROUND/AIMS

Only a few epidemiologic studies on the patients with pulmonary disorders admitted to intensive care unit exist. We investigated the characteristics and clinical outcomes of the patients with severe pulmonary disorders.

METHODS

The sample cohort database of National Health Insurance Sharing Service from 2006 to 2015 was used. Operational definition of critically ill patients was adults who were either admitted to intensive care unit for at least 3 days or expired within first 2 days in the unit. The pulmonary disorder group comprised of critically ill patients with respiratory disease as the main diagnosis.

RESULTS

Among the 997,173 patients, 12,983 (1.3%) in 383 intensive care units were categorized as critically ill. Patients in the pulmonary disorder group tended to have more comorbidities or disabilities. The length of hospital stay and duration of mechanical ventilation were longer in the pulmonary disorder group. Overall mortality and re-admission were higher in the pulmonary disorder group, with adjusted incidence rate ratios of 1.22 (95% confidence interval, 1.18 to 1.27) and 1.26 (95% confidence interval, 1.17 to 1.36), respectively. After adjustment by Cox regression, the pulmonary disorder group was an independent risk factor for in-hospital mortality.

CONCLUSION

In critically ill patients with pulmonary disorder, the use of healthcare resources was higher, and their clinical outcomes were significantly worse than the non-pulmonary disorder group.

Performance of Administrative Algorithms to Identify Interstitial Lung Disease in Rheumatoid Arthritis

OBJECTIVE

To determine the performance of administrative-based algorithms for classifying interstitial lung disease (ILD) complicating rheumatoid arthritis (RA).

METHODS

Participants in a large, multicenter RA registry were screened for ILD using codes from the International Classification of Diseases, Ninth Revision (ICD-9) and the ICD-10. Medical record review confirmed ILD among participants screening positive and a random sample of those screening negative. ICD and procedure codes, provider specialty, and dates were extracted from Veterans Affairs administrative data to construct ILD algorithms. Performance of these algorithms against medical record review was assessed by sensitivity, specificity, positive predictive value (PPV), negative predictive value, and kappa using inverse probability weighting to account for sampling methods.

RESULTS

Medical records of 536 RA patients were reviewed, confirming 182 (stringent definition) and 203 (relaxed definition) cases of ILD. Initially, we identified ≥2 ICD codes from inpatient or outpatient encounters as optimal discriminating factors (specificity 96.0%, PPV 65.5%; κ = 0.70). Subsequently, we constructed a set of ICD-9 and ICD-10 codes that improved algorithm specificity (specificity 96.8%, PPV 69.5%; κ = 0.72). Algorithms that included a pulmonologist diagnosis or chest computed tomography plus pulmonary function testing or lung biopsy had improved performance (specificity 98.0%, PPV 77.4%; κ = 0.75). PPV increased with exclusion of other ILD causes (78.5%) in comparison with the relaxed ILD definition (82.4%) and in sensitivity analyses (83.4-86.3%). Gains in specificity and PPV with greater algorithm requirements were accompanied by declines in sensitivity.

CONCLUSION

Administrative algorithms with optimal combinations of ICD codes, provider specialty, diagnostic testing, and exclusion of other ILD causes accurately classify ILD in RA.

Outcomes of Older Patients with Pulmonary Fibrosis and Non-Small Cell Lung Cancer

Rationale: Characteristics and outcomes of lung cancer in patients with idiopathic pulmonary fibrosis (IPF) in the United States remain understudied.Objectives: To determine the tumor characteristics and survival of patients with IPF with non-small cell lung cancer (NSCLC) using U.S. population-based data.Methods: We selected Medicare beneficiaries from the Surveillance, Epidemiology, and End Results registry with histologically confirmed NSCLC diagnosed between 2007 and 2011. IPF was identified using two validated claims-based algorithms. We compared tumor characteristics and used logistic and Cox regression to compare rates of stage-appropriate therapy and of overall and lung cancer-specific survival in those with IPF and without IPF.Results: A total of 54,453 patients with NSCLC were included. Those with IPF were more likely to be diagnosed at an earlier stage (P < 0.01) and to have squamous histology (46% vs. 35%; P < 0.01) and lower-lobe tumors (38% vs. 28%; P < 0.01) than those without IPF. Patients with IPF and stages I-II disease had odds of receiving stage-appropriate therapy similar to patients without IPF who had stages I-II disease (odds ratio [OR], 1.13; 95% confidence interval [CI], 0.89-1.43); however, those with advanced disease were less likely to be treated (OR, 0.82; 95% CI, 0.68-0.99). Overall and lung cancer-specific survival were worse in patients with IPF (respectively, hazard ratio [HR], 1.35; 95% CI, 1.26-1.45; and HR, 1.21; 95% CI, 1.10-1.32).Conclusions: NSCLC has a unique presentation in patients with IPF and is associated with poorer prognosis. Further research is needed to identify optimal treatment strategies in this population.

Idiopathic Pulmonary Fibrosis and Lung Cancer. A Systematic Review and Meta-analysis

Rationale: The association between idiopathic pulmonary fibrosis (IPF) and lung cancer has been previously reported. However, there is the potential for significant confounding by age and smoking, and an accurate summary risk estimate has not been previously ascertained.Objectives: To determine the risk and burden of lung cancer in patients with IPF, accounting for known confounders.Methods: We conducted a comprehensive literature search of MEDLINE, EMBASE, and SCOPUS databases and used the Newcastle Ottawa criteria to assess study quality. We then assessed the quality of ascertainment of IPF cases based on modern consensus criteria. Data that relied on administrative claims or autopsies were excluded. We calculated summary risk estimates using a random effects model.Results: Twenty-five cohort studies were included in the final analysis. The estimated adjusted incidence rate ratio from two studies was 6.42 (95% confidence interval [CI], 3.21-9.62) and accounted for age, sex, and smoking. The summary incidence rate from 11 studies was 2.07 per 100 person-years (95% CI, 1.46-2.67), and the summary mortality rate was 1.06 per 100 person-years (95% CI, 0.62-1.51) obtained from three studies. The summary prevalence from 11 studies was 13.74% (95% CI, 10.17-17.30), and the proportion of deaths attributable to lung cancer was 10.20 (95% CI, 8.52-11.87) and was obtained from nine studies.Conclusions: IPF is an increased independent risk factor for lung cancer, even after accounting for smoking. Further well-designed studies using modern consensus criteria are needed to explore mechanisms of this association.

Impact of Idiopathic Pulmonary Fibrosis on Longitudinal Health-care Utilization in a Community-Based Cohort of Patients

BACKGROUND

Idiopathic pulmonary fibrosis (IPF) is a rare, chronic lung disease associated with substantial symptom burden, morbidity, and cost. Delivery of high-quality effective care in IPF requires understanding health-care resource utilization (HRU) patterns; however, longitudinal data from real-world populations are limited.

RESEARCH QUESTION

This study aimed to define HRU attributable to IPF by evaluating a longitudinal cohort of community patients with IPF compared with matched control subjects.

STUDY DESIGN AND METHODS

Incident IPF cases were identified in the Kaiser Permanente Northern California electronic health records (2000-2015) using case-validated code-based algorithms. IPF cases were compared with matched control subjects by age, sex, and length of enrollment. Annual rates of HRU measures were assessed during the 5 years pre- and postdiagnosis. Poisson generalized estimating equations were used to estimate adjusted case-control differences in HRU. IPF treatment trends were assessed before and after the availability of IPF-specific medications.

RESULTS

A total of 691 IPF cases were identified and matched with 3,452 control subjects. Adjusted rates of all diagnostic procedures were significantly increased (P < .001) for IPF cases compared with control subjects in both the pre- and postindex periods, including chest CT scans (pre-relative risk [RR], 80.35; post-RR, 32.79), 6-min walk tests (pre-RR, 20.81; post-RR, 34.49), and pulmonary function tests (pre-RR, 9.50; post-RR, 13.24). All-cause hospitalizations (pre-RR, 1.42; post-RR, 2.33) and outpatient visits (pre-RR, 1.22; post-RR, 1.80) were significantly higher among cases compared with control subjects during both the preindex (P < .05) and postindex (P < .001) periods. We observed use of immunosuppressive and IPF-specific therapies prior to diagnosis, and high rates of corticosteroid use before and after diagnosis.

INTERPRETATION

This study defines a marked increase in HRU in patients with IPF compared with control subjects, with accelerated use beginning at least 1 year prediagnosis and elevated use sustained over the following 5 years. To our knowledge, this is the first study to evaluate longitudinal medication trends in IPF. Collectively, this information is foundational to advancing IPF care delivery models and supporting clinical decision-making.

The Role of Palliative Care in Reducing Symptoms and Improving Quality of Life for Patients with Idiopathic Pulmonary Fibrosis: A Review

Idiopathic pulmonary fibrosis (IPF) is a progressive fibrotic lung disease with a median survival of 3-4 years from time of initial diagnosis, similar to the time course of many malignancies. A hallmark of IPF is its unpredictable disease course, ranging from long periods of clinical stability to acute exacerbations with rapid decompensation. As the disease progresses, patients with chronic cough and progressive exertional dyspnea become oxygen dependent. They may experience significant distress due to concurrent depression, anxiety, and fatigue, which often lead to increased symptom burden and decreased quality of life. Despite these complications, palliative care is an underutilized, and often underappreciated, resource before end-of-life care in this population. While there is growing recognition about early palliative care in IPF, current data suggest referral patterns vary widely based on institutional practices. In addition to focusing on symptom management, there is emphasis on supplemental oxygen use, pulmonary rehabilitation, quality of life, and end-of-life care. Importantly, increased use of support groups and national foundation forums have served as venues for further disease education, communication, and advanced care planning outside of the hospital settings. The purpose of this review article is to discuss the clinical features of IPF, the role of palliative care in chronic disease management, current data supporting benefits of palliative care in IPF, its role in symptom management, and practices to help patients and their caregivers achieve their best quality of life.

Validation of claims-based algorithms to identify interstitial lung disease in patients with rheumatoid arthritis

OBJECTIVE

To develop and validate claims-based algorithms to identify interstitial lung disease (ILD) in patients with rheumatoid arthritis (RA) METHODS: Using Medicare claims data linked with the electronic medical records (2012-2014), we first selected RA patients based on ≥2 diagnostic codes for RA and ≥1 disease-modifying antirheumatic drugs.Then, to identify ILD in RA, we developed eight claims-based algorithms using a combination of ICD-9 diagnosis codes and procedure codes related to the diagnosis or management of ILD. We assessed the positive predictive value (PPV) for each of the eight algorithms relative to confirmed ILD cases using chest computerized tomography or lung biopsy as the gold standard.

RESULTS

A total of 5,214 RA patients were included in the study, and the ILD cases identified by each algorithm ranged from 181 to 993. The PPV of the diagnosis code-based algorithms ranged from 43.4% (≥1 diagnosis code by any physician) to 52.0% (≥2 diagnosis codes by any physician). When the algorithms further required ≥1 procedure code (e.g., imaging, bronchoscopy), the PPV did not improve. However, the algorithms that required ILD diagnosis codes by specialists (i.e., pulmonologist or rheumatologist) had PPVs of 61.5% with ≥1 code; 72.4% with ≥2 codes.

CONCLUSIONS

In a cohort of RA patients, our algorithm that required ≥2 ILD diagnosis codes by specialists demonstrated a PPV of 72.4% in ascertaining ILD. Our results support the utility of the claims-based algorithm to identify a population-based cohort of RA patients with ILD using large administrative claims data.

Characterizing Health Outcomes in Idiopathic Pulmonary Fibrosis using US Health Claims Data

BACKGROUND

Idiopathic pulmonary fibrosis (IPF) is a life-threatening interstitial lung disease (ILD). Characterizing health outcomes of IPF patients is challenging due to disease rarity.

OBJECTIVE

This study aimed to identify the burden of disease in patients newly diagnosed with IPF.

METHODS

Patients with ≥1 claim with an IPF diagnosis were identified from a United States healthcare insurer's database (2000-2013). Patients with other known causes of ILD or aged <40 years were excluded. Subgroups were compared based on the 2011 change in International Classification of Diseases, 9th Revision (ICD-9) definition of IPF and occurrence of IPF testing. The prevalence and incidence of preselected health conditions of clinical interest were estimated.

RESULTS

Median age of newly diagnosed patients (n = 7,298) was 62 years (54.0% male). Restricting to patients with IPF diagnostic testing did not substantially affect cohort characteristics, nor did ICD-9 IPF coding change. Mean follow-up was 1.7 years; 16.8% of patients died; and a substantial proportion of patients were censored due to end of health plan enrollment (50.7%) and other causes of ILD (19.6%). The incidence of pulmonary hypertension, lung cancer, and claims-based algorithm proxy for acute respiratory worsening of unknown cause was 22.5, 17.6, and 12.6 per 1,000 person-years, respectively.

CONCLUSIONS

Patients with IPF had a high disease burden with a variety of health outcomes observed, including a high rate of mortality. Database censoring due to changes in enrollment or other ILD diagnoses limited follow-up. Altering cohort entry definitions, including IPF testing or ICD-9 IPF coding change, had little impact on cohort baseline characteristics.

Improving the reactivity of hydrazine-bearing MRI probes for in vivo imaging of lung fibrogenesis

Pulmonary fibrosis (PF) is the pathologic accumulation of extracellular matrix components in lung tissue that result in scarring following chronic lung injury. PF is typically diagnosed by high resolution computed tomography (HRCT) and/or invasive biopsy. However, HRCT cannot distinguish old injury from active fibrogenesis. We previously demonstrated that allysine residues on oxidized collagen represent an abundant target during lung fibrogenesis, and that magnetic resonance imaging (MRI) with a small-molecule, gadolinium-containing probe, Gd-Hyd, could specifically detect and stage fibrogenesis in a mouse model. In this work, we present an improved probe, Gd-CHyd, featuring an N,N-dialkyl hydrazine which has an order of magnitude both greater reactivity and affinity for aldehydes. In a paired study in mice with bleomycin induced lung injury we show that the improved reactivity and affinity of Gd-CHyd results in significantly higher lung-to-liver contrast, e.g. 77% higher at 45 min post injection, and slower lung clearance than Gd-Hyd. Gd-CHyd enhanced MRI is >60-fold higher in bleomycin injured mouse lungs compared to uninjured mice. Collectively, our data indicate that enhancing hydrazine reactivity and affinity towards allysine is an effective strategy to significantly improve molecular MRI probes for lung fibrogenesis.

Centralized expert HRCT Reading in suspected idiopathic pulmonary fibrosis: Experience from an Eurasian teleradiology program

PURPOSE

To share experience from a large, ongoing expert reading teleradiology program in Europe and Asia aiming at supporting referring centers to interpret high-resolution computed tomography (HRCT) with respect to presence of Usual Interstitial Pneumonia (UIP)-pattern in patients with suspected Idiopathic Pulmonary Fibrosis (IPF).

METHOD

We analyzed data from 01/2014 to 05/2019, including HRCTs from 239 medical centers in 12 European and Asian countries that were transmitted to our Picture Archiving and Communication System (PACS) via a secured internet connection. Structured reports were generated in consensus by a radiologist with over 20 years of experience in thoracic imaging and a pulmonologist with specific expertise in interstitial lung disease according to current guidelines on IPF. Reports were sent to referring physicians. We evaluated patient characteristics, technical issues, report turnaround times and frequency of diagnoses. We also conducted a survey to collect feedback from referring physicians.

RESULTS

HRCT image data from 703 patients were transmitted (53.5% male). Mean age was 63.7 years (SD:17). In 35.1% of all cases diagnosis was "UIP"/"Typical UIP". The mean report turnaround time was 1.7 days (SD:2.9). Data transmission errors occurred in 7.1%. Overall satisfaction rate among referring physicians was high (8.4 out of 10; SD:3.2).

CONCLUSIONS

This Eurasian teleradiology program demonstrates the feasibility of cross-border teleradiology for the provision of state-of-the-art reporting despite heterogeneity of referring medical centers and challenges like data transmission errors and language barriers. We also point out important factors for success like the usage of structured reporting templates.

In-Hospital Mortality in Patients with Idiopathic Pulmonary Fibrosis: A US Cohort Study

Purpose

In patients with idiopathic pulmonary fibrosis (IPF), hospitalizations are associated with high mortality. We sought to determine in-hospital mortality rates and factors associated with in-hospital mortality in patients with IPF.

Methods

Patients with IPF were identified from the Premier Healthcare Database, a representative administrative dataset that includes > 20% of hospital discharges in the US, using an algorithm based on diagnostic codes and billing data. We used logistic regression to analyze associations between patient-, hospital-, and treatment-related characteristics and a composite primary outcome of death during the index visit, lung transplant during the index visit and > 1 day after admission, or death during a readmission within 90 days.

Results

The cohort comprised 6665 patients with IPF hospitalized between October 2011 and October 2014. A total of 963 (14.4%) met the primary outcome. Factors significantly associated with a higher risk of the primary outcome included mechanical ventilation [odds ratio 4.65 (95% CI 3.73, 5.80)], admission to the intensive care unit [1.83 (1.52, 2.21)], treatment with opioids (3.06 [2.57, 3.65]), and a diagnosis of pneumonia [1.44 (1.21, 1.71)]. Factors significantly associated with a lower risk included concurrent chronic obstructive pulmonary disease [0.65 (0.55, 0.77)] and female sex [0.67 (0.57, 0.79)].

Conclusions

Patients with IPF, particularly those receiving mechanical ventilation or intensive care, are at substantial risk of death or lung transplant during hospitalization or death during a readmission within 90 days.

Electronic supplementary material

The online version of this article (10.1007/s00408-019-00270-z) contains supplementary material, which is available to authorized users.

De novo lung biofabrication: clinical need, construction methods, and design strategy

Chronic lung disease is the 4th leading cause of death in the United States. Due to a shortage of donor lungs, alternative approaches to support failing, native lungs have been attempted, including mechanical ventilation and various forms of artificial lungs. However, each of these support methods causes significant complications when used for longer than a few days and are thus not capable of long-term support. For artificial lungs, complications arise due to interactions between the artificial materials of the device and the blood of the recipient. A potential new approach is the fabrication of lungs from biological materials, such that the gas exchange membranes provide a more biomimetic blood-contacting interface. Recent advancements with three-dimensional, soft-tissue biofabrication methods and the engineering of thin, basement membranes demonstrate the potential of fabricating a lung scaffold from extracellular matrix materials. This scaffold could then be seeded with endothelial and epithelial cells, matured within a bioreactor, and transplanted. In theory, this fully biological lung could provide improved, long-term biocompatibility relative to artificial lungs, but significant work is needed to perfect the organ design and construction methods. Like artificial lungs, biofabricated lungs do not need to follow the shape and structure of a native lung, allowing for simpler manufacture. However, various functional requirements must still be met, including stable, efficient gas exchange for a period of years. Design decisions depend on the disease state, how the organ is implanted, and the latest biofabrication methods available in a rapidly evolving field.

The Anti-Fibrotic Effects of CG-745, an HDAC Inhibitor, in Bleomycin and PHMG-Induced Mouse Models

Idiopathic pulmonary fibrosis (IPF) is a fatal lung disease with poor prognosis and progression to lung fibrosis related to genetic factors as well as environmental factors. In fact, it was discovered that in South Korea many people who used humidifier disinfectants containing polyhexamethylene guanidine (PHMG), died of lung fibrosis. Currently two anti-fibrotic drugs, pirfenidone and nintedanib, have been approved by the FDA, but unfortunately, do not cure the disease. Since the histone deacetylase (HDAC) activity is associated with progression to chronic diseases and with fibrotic phenomena in the kidney, heart and lung tissues, we investigated the anti-fibrotic effects of CG-745, an HDAC inhibitor. After lung fibrosis was induced in two animal models by bleomycin and PHMG instillation, the regulation of fibrosis and epithelial mesenchymal transition (EMT)-related markers was assessed. CG-745 exhibited potent prevention of collagen production, inflammatory cell accumulation, and cytokines release in both models. Additionally, N-cadherin and vimentin expression were lowered significantly by the treatment of CG-745. The anti-fibrotic effects of CG-745 proven by the EMT regulation may suggest a potential therapeutic effect of CG-745 on lung fibrosis.