Idiopathic Pulmonary Fibrosis Population Research Articles

Antifibrotics and mortality in idiopathic pulmonary fibrosis: external validity and avoidance of immortal time bias

Background and objectivePooled analyses of previous randomized controlled trials reported that antifibrotics improved survival in patients with idiopathic pulmonary fibrosis (IPF), but the results were only based on short-term outcome data from selected patients who met strict criteria. Observational studies/meta-analyses also suggested that antifibrotics improve survival, but these studies failed to control for immortal time bias that considerably exaggerates drug effects. Therefore, whether antifibrotics truly improve long-term survival in patients with IPF in the real world remains undetermined and requires external validity.MethodsWe used data from the Japanese National Claims Database to estimate the intention-to-treat effect of antifibrotics on mortality. To address immortal time bias, we employed models treating antifibrotic initiation as a time-dependent covariate and target trial emulation (TTE), both incorporating new-user designs for antifibrotics and treating lung transplantation as a competing event.ResultsOf 30,154 patients with IPF, 14,525 received antifibrotics. Multivariate Fine–Gray models with antifibrotic initiation as a time-dependent covariate revealed that compared with no treatment, nintedanib (adjusted hazard ratio [aHR], 0.85; 95% confidence interval [CI], 0.81–0.89) and pirfenidone (aHR, 0.89; 95% CI, 0.86–0.93) were associated with reduced mortality. The TTE model also replicated the associations of nintedanib (aHR, 0.69; 95% CI, 0.65–0.74) and pirfenidone (aHR, 0.81; 95% CI, 0.78–0.85) with reduced mortality. Subgroup analyses confirmed this association regardless of age, sex, and comorbidities, excluding certain subpopulations.ConclusionsThe results of this large-scale real-world analysis support the generalizability of the association between antifibrotics and improved survival in various IPF populations.

Integrative analysis reveals the recurrent genetic etiologies in idiopathic pulmonary fibrosis.

Idiopathic pulmonary fibrosis (IPF) is increasingly recognized as a chronic, progressive and fatal lung disease with an unknown etiology. Current studies focus on revealing the genetic factors in the risk of IPF, making the integrative analysis of genetic variations and transcriptomic alterations of substantial value. This study aimed to improve the understanding of the molecular basis of IPF through an integrative analysis of whole-exome sequencing (WES), bulk RNA sequencing (RNA-seq) and single-cell RNA sequencing (scRNA-seq) data. WES is a powerful tool for studying the genetic basis of IPF, allowing for the identification of genetic variants that may be associated with the development of the disease. RNA-seq data provide a comprehensive view of the transcriptional changes in IPF patients, while scRNA-seq data offer a more granule view of cell-type-specific alterations. In this study, we identified a comprehensive mutational landscape of recurrent genomic and transcriptomic variations, including single-nucleotide polymorphisms, CNVs and differentially expressed genes, in IPF populations, which may play a significant role in the development and progression of IPF. Our study provided valuable insights into the genetic and transcriptomic variations associated with IPF, revealing changes in gene expression that may contribute to disease development and progression. These findings highlight the importance of an integrative approach to understanding the molecular mechanisms underlying IPF and may pave the way for identifying potential therapeutic targets.

Lung Transplant Outcomes for Idiopathic Pulmonary Fibrosis: Are We Improving?

Following implementation of the Lung Allocation Score in 2005, idiopathic pulmonary fibrosis (IPF) emerged as the most common indication for lung transplant (LT) in the United States. The age and comorbidity of patients receiving LT have since increased and the indications for LT have evolved. However, limited data have analyzed more recent outcomes among the IPF population. We analyzed LTs for the primary indication of IPF using the United Network for Organ Sharing database. We performed an eras-based analysis, comparing patient characteristics, survival, and related outcomes during 2005-2009 (Era 1) and 2010-2014 (Era 2) with Chi square, Wilcoxon rank sum, and Kaplan-Meier analyses. We compared 1-year survival from 2005-2020 and survival at milestones ranging from 1-month to 5-years. We conducted two adjusted Cox proportional hazards models: 5-year survival by era and 1-year survival annually from 2010-2020. From Era 1 (n=1818) to Era 2 (n=3227), the median age of LT recipients increased from 61 to 63 years old (p<0.001). Patients in the intensive care unit prior to LT climbed from 7.7% to 12.1% (p<0.001), and patients with diabetes grew from 17.9% to 19.4% (p=0.003). Despite increased severity of illness, 5-year survival increased from 51.9% in Era 1 to 55.2% in Era 2 (p=0.02). Adjusted modeling indicated that LT during Era 2 featured a 17% hazard reduction compared to Era 1 (Hazard Ratio = 0.83, 95% CI: 0.76-0.91). Survival is improving for patients undergoing LT for IPF, despite the challenges of transplantation patients with progressively higher risk profiles.

Weak to no correlation between quantitative high-resolution computed tomography metrics and lung function change in fibrotic diseases.

Identifying systemic sclerosis (SSc) and idiopathic pulmonary fibrosis (IPF) patients at risk of more rapid forced vital capacity (FVC) decline could improve trial design. The purpose of the present study was to explore the prognostic value of quantitative high-resolution computed tomography (HRCT) metrics derived by Imbio lung texture analysis (LTA) tool in predicting FVC slope. This retrospective study used data from patients who were not treated with investigational drugs with and without background antifibrotic therapies in tocilizumab phase 3 SSc, lebrikizumab phase 2 IPF, and zinpentraxin alfa phase 2 IPF studies conducted from 2015 to 2021. Controlled HRCT axial volumetric multidetector computed tomography scans were evaluated using the Imbio LTA tool. Associations between HRCT metrics and FVC slope were assessed through the Spearman correlation coefficient and adjusted R2 in a linear regression model adjusted by demographics and baseline clinical characteristics. A total of 271 SSc and IPF patients were analysed. Correlation coefficients of highest magnitude were observed in the SSc study between the extent of ground glass, normal volume, quantification of interstitial lung disease, reticular pattern, and FVC slope (-0.25, 0.28, -0.28, and -0.33, respectively), while the correlation coefficients observed in IPF studies were in general <0.2. The incremental prognostic value of the baseline HRCT metrics was marginal after adjusting baseline characteristics and was inconsistent across study arms. Data from the SSc and IPF studies suggested weak to no and inconsistent correlation between quantitative HRCT metrics derived by the Imbio LTA tool and FVC slope in the studied SSc and IPF population.

Eligibility criteria from pharmaceutical randomised controlled trials of idiopathic pulmonary fibrosis: a registry-based study.

Little is known about generalisability of randomised controlled trials (RCTs) for idiopathic pulmonary fibrosis (IPF). We evaluated eligibility criteria for phase III IPF RCTs to determine their representativeness in clinical registries, and calculated forced vital capacity (FVC) changes according to eligibility criteria. Common eligibility criteria used in >60% of IPF RCTs were identified from a literature search and applied to patients with IPF from prospective Australian and Canadian registries. Additional pre-specified criteria of 6-min walk distance (6MWD) and different measures of preceding disease progression were also evaluated. Joint longitudinal-survival modelling was used to compare FVC decline according to eligibility for individual and composite criteria. Out of 990 patients with IPF, 527 (53%) met all common RCT eligibility criteria at the first clinic visit, including 343 with definite IPF and 184 with radiological probable usual interstitial pneumonia pattern without histological confirmation (i.e. provisional IPF). The percentages of eligible patients for landmark RCTs of nintedanib and pirfenidone were 19-50%. Adding 6MWD ≥150 m and different measures of preceding disease progression to the composite common criteria reduced the percentages of patients meeting eligibility to 52% (n=516) and 4-18% (n=12-61), respectively. Patients meeting the composite common criteria had less-rapid 1-year FVC decline than those who did not (-90 versus -103 mL, p=0.01). Definite IPF generally had more-rapid 1-year FVC decline compared to provisional IPF. Eligibility criteria of previous IPF RCTs have limited generalisability to clinical IPF populations, with FVC decline differing between eligible and ineligible populations.

MUC5B rs35705950 minor allele associates with older age and better survival in idiopathic pulmonary fibrosis.

The minor T-allele of the MUC5B promoter polymorphism rs35705950 is strongly associated with idiopathic pulmonary fibrosis (IPF). However, conflicting results have been reported on the relationship between the MUC5B minor allele and survival and it is unknown whether a specific subgroup of IPF patients might benefit from MUC5B minor allele carriage. We investigated the association between MUC5B rs35705950, survival and patient characteristics in a real-world population of European IPF patients. In this retrospective study, 1751 patients with IPF from 8 European centres were included. MUC5B rs35705950 genotype, demographics, clinical characteristics at diagnosis and survival data were analysed. In a multi-variate Cox proportional hazard model the MUC5B minor allele was a significant independent predictor of survival when adjusted for age, sex, high resolution computed tomography pattern, smoking behaviour and pulmonary function tests in IPF. MUC5B minor allele carriers were significantly older at diagnosis (p=0.001). The percentage of MUC5B minor allele carriers increased significantly with age from 44% in patients aged <56 year, to 63% in patients aged >75. In IPF patients aged <56, the MUC5B minor allele was not associated with survival. In IPF patients aged ≥56, survival was significantly better for MUC5B minor allele carriers (45 months [CI: 42-49]) compared to non-carriers (29 months [CI: 26-33]; p=4 × 10-12 ). MUC5B minor allele carriage associates with a better median transplant-free survival of 16 months in the European IPF population aged over 56 years. MUC5B genotype status might aid disease prognostication in clinical management of IPF patients.

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

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. 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. 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.

Air pollution and hospitalization of patients with idiopathic pulmonary fibrosis in Beijing: a time-series study

BackgroundA small number of studies suggested that air pollution was associated with idiopathic pulmonary fibrosis (IPF) exacerbation, incidence and mortality. However, no studies to date were conducted in regions where air pollution is substantial. We aimed to investigate whether there are associations between acute increases in air pollution and hospitalization of patients with a confirmed primary diagnosis of IPF in Beijing.MethodsDaily count of IPF hospitalizations (International Classification of Disease-10th Revision, J84.1) was obtained from an administrative database for 2013–2017 while daily city-wide average concentrations of PM10, PM2.5, NO2, Ozone, SO2 were obtained from 35 municipal monitoring stations for the same period. The association between daily IPF hospitalization and average concentration of each pollutant was analyzed with a generalized additive model estimating Poisson distribution.ResultsDaily 24-h mean PM2.5 concentration during 2013–2017 was 76.7 μg/m3. The relative risk (RR) of IPF hospitalization per interquartile range (IQR) higher (72 μg/m3) in PM2.5 was 1.049 (95% CI 1.024–1.074) and 1.031 (95% CI 1.007–1.056) for lag0 and moving averages 0–1 days respectively. No significant associations were observed for other lags. Statistically significant positive associations were also observed at lag0 with SO2, Ozone and NO2 (in men only). Positive associations were seen at moving averages 0–30 days for PM10 (RR per 86 μg/m3: 1.021, 95% CI 0.994–1.049), NO2 (RR per 30 μg/m3: 1.029, 95% CI 0.999–1.060), and SO2 (RR per 15 μg/m3: 1.060 (95% CI 1.025–1.097), but not with PM2.5 or Ozone.ConclusionsDespite improvement in air quality since the implementation of clean air policy in 2013, acute exposure to higher levels of air pollution is significantly associated with IPF hospitalization in Beijing. Air quality policy should be continuously enforced to protect vulnerable IPF populations as well as the general public.

The Effect of Cardiovascular Medications on Disease-Related Outcomes in Idiopathic Pulmonary Fibrosis: A Systematic Review and Meta-Analysis

Background: Multiple studies have revealed that idiopathic pulmonary fibrosis (IPF) patients are more at risk for cardiovascular diseases and that many IPF patients receive cardiovascular medications like statins, angiotensin-converting enzyme inhibitor (ACEI), angiotensin receptor blocker (ARB), and anticoagulants. Existing studies have reported divergent findings on the link between cardiovascular medications and fibrotic disease processes. The aim of this study is to synthesize the evidence on the efficacy of cardiovascular medications in IPF. Methods: We searched studies reporting the effect of cardiovascular medications on IPF in the PubMed, Embase, Web of Science, Cochrane Library, and two Chinese databases (China National Knowledge Infrastructure database and China Wanfang database). We calculated survival data, forced vital capacity (FVC) decline, and IPF-related mortality to assess the efficacy of cardiovascular medications in IPF. We also estimated statistical heterogeneity by using I2 and Cochran Q tests, and publication bias was evaluated by risk of bias tools ROBINS-I. Results: A total of 12 studies were included in the analysis. The included studies had moderate-to-serious risk of bias. Statin use was associated with a reduction in mortality (hazard ratio (HR), 0.89; 95% CI 0.83–0.97). Meta-analysis did not demonstrate any significant relationship between statin use and the FVC decline (HR, 0.86; 95% CI 0.73–1.02), ACEI/ARB use, and survival data (HR, 0.92; 95% CI 0.73–1.15) as well as anticoagulant use and survival data (HR, 1.16; 95% CI 0.62–2.19). Conclusion: Our study suggested that there is a consistent relationship between statin therapy and survival data in IPF population. However, there is currently insufficient evidence to conclude the effect of ACEI, ARB, and anticoagulant therapy on IPF population especially to the disease-related outcomes in IPF.

Outcomes of patients with advanced idiopathic pulmonary fibrosis treated with nintedanib or pirfenidone in a real-world multicentre cohort.

Antifibrotic therapy with nintedanib or pirfenidone slows disease progression and reduces mortality in patients with idiopathic pulmonary fibrosis (IPF). However, patients with advanced IPF, as defined by forced vital capacity (FVC) < 50% and/or diffusion capacity for carbon monoxide (DLCO) < 30% of predicted, have not been included in randomized trials, and the outcomes of such patients who initiate treatment are not well understood. We determined lung function, disease progression and mortality outcomes following initiation of antifibrotic therapy in patients with advanced IPF at the time of treatment initiation compared to those with mild-moderate IPF. We included 502 patients enrolled in IPF registries from four Nordic countries. Linear mixed models were used to assess change in FVC and DLCO over time. Cox proportional hazards models were used to assess transplant-free survival and progression- and transplant-free survival. Of 502 patients, 66 (13%) had advanced IPF. Annual change in FVC was -125 ml (95% CI -163, -87) among patients with mild-moderate IPF, and +28 ml (95% CI -96, +152) among those with advanced IPF. Advanced IPF at treatment initiation was associated with poorer transplant-free survival (hazard ratio [HR] 2.39 [95% CI 1.66, 3.43]) and progression- and transplant-free survival (HR 1.60 [95% CI 1.15, 2.23]). In a broadly representative IPF population, patients with advanced IPF at the initiation of antifibrotic therapy did not have greater lung function decline over time compared with those with mild-moderate IPF, but had substantially higher mortality. Prospective studies are needed to determine the effect of antifibrotic therapy in patients with advanced IPF.

Pleuroparenchymal fibroelastosis in idiopathic pulmonary fibrosis: Survival analysis using visual and computer-based computed tomography assessment.

BackgroundIdiopathic pulmonary fibrosis (IPF) and pleuroparenchymal fibroelastosis (PPFE) are known to have poor outcomes but detailed examinations of prognostic significance of an association between these morphologic processes are lacking.MethodsRetrospective observational study of independent derivation and validation cohorts of IPF populations. Upper-lobe PPFE extent was scored visually (vPPFE) as categories of absent, moderate, marked. Computerised upper-zone PPFE extent (cPPFE) was examined continuously and using a threshold of 2·5% pleural surface area. vPPFE and cPPFE were evaluated against 1-year FVC decline (estimated using mixed-effects models) and mortality. Multivariable models were adjusted for age, gender, smoking history, antifibrotic treatment and diffusion capacity for carbon monoxide.FindingsPPFE prevalence was 49% (derivation cohort, n = 142) and 72% (validation cohort, n = 145). vPPFE marginally contributed 3–14% to variance in interstitial lung disease (ILD) severity across both cohorts.In multivariable models, marked vPPFE was independently associated with 1-year FVC decline (derivation: regression coefficient 18·3, 95 CI 8·47–28·2%; validation: 7·51, 1·85–13·2%) and mortality (derivation: hazard ratio [HR] 7·70, 95% CI 3·50–16·9; validation: HR 3·01, 1·33–6·81). Similarly, continuous and dichotomised cPPFE were associated with 1-year FVC decline and mortality (cPPFE ≥ 2·5% derivation: HR 5·26, 3·00–9·22; validation: HR 2·06, 1·28–3·31). Individuals with cPPFE ≥ 2·5% or marked vPPFE had the lowest median survival, the cPPFE threshold demonstrated greater discrimination of poor outcomes at two and three years than marked vPPFE.InterpretationPPFE quantification supports distinction of IPF patients with a worse outcome independent of established ILD severity measures. This has the potential to improve prognostic management and elucidate separate pathways of disease progression.FundingThis research was funded in whole or in part by the Wellcome Trust [209,553/Z/17/Z] and the NIHR UCLH Biomedical Research Centre, UK.

Impact of the new definition for pulmonary hypertension in patients with lung disease: an analysis of the United Network for Organ Sharing database.

The implications of the recent change in the definition of pulmonary hypertension on epidemiology and outcomes are not known. We sought to determine the percentage of patients with the two most common lung diseases that would be reclassified regarding the presence/absence of pulmonary hypertension with the revised definition. A query of the United Network for Organ Sharing database was performed. The percentage of patients meeting the current and previous definition of pulmonary hypertension was described. Outcomes of patients stratified by the current and previous definitions were compared. There were 15,563 patients with right heart catheterization data analyzed. Pulmonary hypertension was more prevalent in both chronic obstructive pulmonary disease and idiopathic pulmonary fibrosis under the new definition at 52.4% versus 82.4%, and 47.6% versus 73.6%, respectively. “Pre-capillary” pulmonary hypertension by the new definition was lower at 28.1% for chronic obstructive pulmonary disease and 36.8% for idiopathic pulmonary fibrosis. Of the patients with pulmonary hypertension by the old definition, 23.9% of chronic obstructive pulmonary disease patients and 18.7% of idiopathic pulmonary fibrosis patients were not classified as pulmonary hypertension by the new definition. Conversely, 15.9% of chronic obstructive pulmonary disease patients and 15.1% of idiopathic pulmonary fibrosis patients who did not meet diagnostic criteria for pulmonary hypertension by the old definition did have pulmonary hypertension by the new definition. Patients in both disease categories had shorter transplant-free waitlist survival in the presence of pulmonary hypertension by both the new and old definitions. There was a trend toward the new definition of pre-capillary pulmonary hypertension better discerning outcomes compared to the old definition of pulmonary hypertension in idiopathic pulmonary fibrosis patients. Most patients with advanced lung disease who are listed for lung transplantation have pulmonary hypertension, but fewer have pre-capillary pulmonary hypertension than pulmonary hypertension by the old definition. Both the old and new definition of precapillary pulmonary hypertension appear to discern outcomes among the two groups of lung disease analyzed, with some evidence to suggest that the new definition performs slightly better in the idiopathic pulmonary fibrosis population.

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 72years, 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.

Insights Into Development and Progression of Idiopathic Pulmonary Fibrosis From Single Cell RNA Studies.

Idiopathic pulmonary fibrosis (IPF) is a progressive and fatal lung disease with limited therapeutic options. The current model suggests that chronic or repetitive “micro-injuries” of the alveolar epithelium lead to activation and proliferation of fibroblasts and excessive extracellular matrix (ECM) deposition. Disruption of alveolar type II (ATII) epithelial cell homeostasis and the characteristics of mesenchymal cell populations in IPF have received particular attention in recent years. Emerging data from single cell RNA sequencing (scRNAseq) analysis shed novel light on alterations in ATII cell progenitor dysfunction and the diversity of mesenchymal cells within the fibrotic lung. Within this minireview, we summarize the data from most recent human scRNAseq studies. We aim to collate the current knowledge on cellular plasticity and heterogeneity in the development and progression of IPF, effects of drug treatment on transcriptional changes. Finally, we provide a brief outlook on future challenges and promises for large scale sequencing studies in the development of novel therapeutics for IPF.

Serial CT analysis in idiopathic pulmonary fibrosis: comparison of visual features that determine patient outcome

AimsPatients with idiopathic pulmonary fibrosis (IPF) receiving antifibrotic medication and patients with non-IPF fibrosing lung disease often demonstrate rates of annualised forced vital capacity (FVC) decline within the range of...

Single-cell RNA-seq reveals ectopic and aberrant lung-resident cell populations in idiopathic pulmonary fibrosis.

We provide a single-cell atlas of idiopathic pulmonary fibrosis (IPF), a fatal interstitial lung disease, by profiling 312,928 cells from 32 IPF, 28 smoker and nonsmoker controls, and 18 chronic obstructive pulmonary disease (COPD) lungs. Among epithelial cells enriched in IPF, we identify a previously unidentified population of aberrant basaloid cells that coexpress basal epithelial, mesenchymal, senescence, and developmental markers and are located at the edge of myofibroblast foci in the IPF lung. Among vascular endothelial cells, we identify an ectopically expanded cell population transcriptomically identical to bronchial restricted vascular endothelial cells in IPF. We confirm the presence of both populations by immunohistochemistry and independent datasets. Among stromal cells, we identify IPF myofibroblasts and invasive fibroblasts with partially overlapping cells in control and COPD lungs. Last, we confirm previous findings of profibrotic macrophage populations in the IPF lung. Our comprehensive catalog reveals the complexity and diversity of aberrant cellular populations in IPF.

Disease Severity and Quality of Life in Patients With Idiopathic Pulmonary Fibrosis: A Cross-Sectional Analysis of the IPF-PRO Registry

Limited data are available on the association between clinically measured disease severity markers and quality of life (QOL) in idiopathic pulmonary fibrosis (IPF). The study examined the associations between objective disease severity metrics and QOL in a contemporary IPF population. This study evaluated baseline data from patients enrolled in the multicenter, US-based Idiopathic Pulmonary Fibrosis Prospective Outcomes Registry between June 2014 and July 2018. Disease severity metrics included FVC %predicted, diffusing capacity for carbon monoxide (Dlco) %predicted, supplemental oxygen use with activity, supplemental oxygen use at rest, and two summary scores (the Gender-Age-Lung Physiology index, based on gender, age, and %predicted values for Dlco and FVC; and the Composite Physiologic Index, based on %predicted values for Dlco, FVC, and FEV1). Multivariable adjusted regression models were used to examine cross-sectional associations between each severity measure and St. George's Respiratory Questionnaire (SGRQ) total score. Among 829 patients with complete SGRQ data, the median (interquartile range) SGRQ score at enrollment was 40 (26-53), with higher scores indicating worse QOL. Modest SGRQ impairments were observed with increasing Gender-Age-Lung Physiology score (2.9 [1.8-4.0] per 1-point increase] and with increasing Composite Physiologic Index scores (3.0 [2.4-3.6] per 5-point increase). Substantial SGRQ impairments were observed for oxygen use with activity (15.6 [12.9-18.2]), oxygen use at rest (16.2 [13.0-19.4]), and decreasing Dlco (5.0 [4.0-6.1] per 10%decrease in %predicted). Objective measures of disease severity, including severity scores, physiologic parameters, and supplemental oxygen use, are associated with worse QOL in patients with IPF. ClinicalTrials.gov; No.: NCT01915511; URL: www.clinicaltrials.gov.

Comorbidity in idiopathic pulmonary fibrosis - what can biomarkers tell us?

Idiopathic pulmonary fibrosis (IPF) is characterized by progressive parenchymal scarring, leading to dyspnoea, respiratory failure and premature death. Although IPF is confined to the lungs, the importance of IPF comorbidities such as pulmonary hypertension and ischaemic heart disease, lung cancer, emphysema/chronic obstructive pulmonary disease, gastroesophageal reflux, sleep apnoea and depression has been increasingly recognized. These comorbidities may be associated with increased mortality and significant loss of quality of life, so their identification and management are vital. The development of good-quality biomarkers could lead to numerous gains in the management of these patients. Biomarkers can be used for the identification of predisposed individuals, early diagnosis, assessment of prognosis, selection of best treatment and assessment of response to treatment. However, the role of biomarkers for IPF comorbidities is still quite limited, and mostly based on evidence coming from populations without IPF. The future development of new biomarker studies could be informed by those that have been studied independently for each of these conditions.For now, clinicians should be mostly attentive to clinical manifestations of IPF comorbidities, and use validated diagnostic methods for diagnosis. As research on biomarkers of most common diseases continues, it is expected that useful biomarkers are developed for these diseases and then validated for IPF populations. The reviews of this paper are available via the supplemental material section.

Defining the Activated Fibroblast Population in Lung Fibrosis Using Single-Cell Sequencing.

Idiopathic pulmonary fibrosis (IPF) is a progressive and fatal lung disorder driven by unrelenting extracellular matrix deposition. Fibroblasts are recognized as the central mediators of extracellular matrix production in IPF; however, the characteristics of the underlying fibroblast cell populations in IPF remain poorly understood. Here, we use an unbiased single-cell RNA sequencing analysis of a bleomycin-induced pulmonary fibrosis model to characterize molecular responses to fibrotic injury. Lung cells were isolated on Day 11 to capture emerging fibrosis and gene expression was analyzed by three complementary techniques, which, together, generated a 49-gene signature that defined an activated subpopulation of fibroblasts. However, none of the identified genes were specific to the activated cells or to the disease setting, implying that the activated fibroblasts are not uniquely defined, but exhibit a similar, yet amplified, gene expression pattern to control cells. Our findings have important implications for fibrosis research, including: 1) defining myofibroblasts with any single marker will fail to capture much of the underlying biology; 2) fibroblast activation is poorly correlated with expression of transforming growth factor-β pathway genes; 3) single-cell analysis provides insight into the mechanism of action of effective therapies (nintedanib); 4) early events in lung fibrosis need not involve significant changes in fibroblast number; populations that do increase in number, such as macrophages, dendritic cells, and proliferating myeloid cells, may merit closer examination for their role in pathogenesis.

The prognostic role of Gender-Age-Physiology system in idiopathic pulmonary fibrosis patients treated with pirfenidone.

Gender, age, physiology (GAP) system have proven to be an easy tool for predicting disease stages and survival in idiopathic pulmonary fibrosis (IPF) patients. To validate mortality risk as determined by the GAP system in a real-life multicentre IPF population treated with pirfenidone. The study included patients who received pirfenidone for at least 6months. The GAP calculator and the GAP index were determined. The primary outcome was all-cause mortality. The prognostic accuracy of the GAP system was evaluated with respect to calibration and discrimination. Sixty-eight IPF patients were enrolled in the study. The median follow-up was 2.4 years (range 0.1-7.4 years). A total of 22 deaths as first event (32%) and of 10 lung transplantation (15%) were recorded. The cumulative incidence of mortality at 1, 2 and 3 years was 10.4%, 22.4% and 38.4%, respectively. The differences between the predicted and observed mortality were not significant for the GAP index while the observed mortality become comparable to that predicted by the GAP calculator only in the third year of follow-up. The C-index for the GAP index was 0.74 (95% CI 0.57-0.93) while the C-statistic value for the GAP calculator was 0.77 (95% CI 0.59-0.95).