Christopher J. Ryerson

A Multidimensional Index and Staging System for Idiopathic Pulmonary Fibrosis

BACKGROUND Idiopathic pulmonary fibrosis (IPF) is a progressive fibrotic lung disease with an overall poor prognosis. A simple-to-use staging system for IPF may improve prognostication, help guide management, and facilitate research. OBJECTIVE To develop a multidimensional prognostic staging system for IPF by using commonly measured clinical and physiologic variables. DESIGN A clinical prediction model was developed and validated by using retrospective data from 3 large, geographically distinct cohorts. SETTING Interstitial lung disease referral centers in California, Minnesota, and Italy. PATIENTS 228 patients with IPF at the University of California, San Francisco (derivation cohort), and 330 patients at the Mayo Clinic and Morgagni-Pierantoni Hospital (validation cohort). MEASUREMENTS The primary outcome was mortality, treating transplantation as a competing risk. Model discrimination was assessed by the c-index, and calibration was assessed by comparing predicted and observed cumulative mortality at 1, 2, and 3 years. RESULTS Four variables were included in the final model: gender (G), age (A), and 2 lung physiology variables (P) (FVC and Dlco). A model using continuous predictors (GAP calculator) and a simple point-scoring system (GAP index) performed similarly in derivation (c-index of 70.8 and 69.3, respectively) and validation (c-index of 69.1 and 68.7, respectively). Three stages (stages I, II, and III) were identified based on the GAP index with 1-year mortality of 6%, 16%, and 39%, respectively. The GAP models performed similarly in pooled follow-up visits (c-index ≥71.9). LIMITATION Patients were drawn from academic centers and analyzed retrospectively. CONCLUSION The GAP models use commonly measured clinical and physiologic variables to predict mortality in patients with IPF.

Acute Exacerbation of Idiopathic Pulmonary Fibrosis. An International Working Group Report

Acute exacerbation of idiopathic pulmonary fibrosis has been defined as an acute, clinically significant, respiratory deterioration of unidentifiable cause. The objective of this international working group report on acute exacerbation of idiopathic pulmonary fibrosis was to provide a comprehensive update on the topic. A literature review was conducted to identify all relevant English text publications and abstracts. Evidence-based updates on the epidemiology, etiology, risk factors, prognosis, and management of acute exacerbations of idiopathic pulmonary fibrosis are provided. Finally, to better reflect the current state of knowledge and improve the feasibility of future research into its etiology and treatment, the working group proposes a new conceptual framework for acute respiratory deterioration in idiopathic pulmonary fibrosis and a revised definition and diagnostic criteria for acute exacerbation of idiopathic pulmonary fibrosis.

Clinical features and outcomes in combined pulmonary fibrosis and emphysema in idiopathic pulmonary fibrosis

BACKGROUND Combined pulmonary fibrosis and emphysema (CPFE) is increasingly recognized, but its prevalence and prognosis remain unclear. We sought to determine the prevalence, clinical features, and prognosis of CPFE in idiopathic pulmonary fibrosis (IPF), using a standardized and reproducible definition. METHODS Patients with IPF were identified from two ongoing cohorts. Two radiologists scored emphysema and fibrosis severity on high-resolution CT (HRCT) scans. CPFE was defined as ≥10% emphysema on HRCT scan. Clinical characteristics and outcomes of patients with CPFE and IPF and those with non-CPFE IPF were compared with unadjusted analysis and then analysis after adjustment for HRCT fibrosis score. Mortality was compared using competing risks regression to handle lung transplantation. Sensitivity analyses were performed using Cox proportional hazards, including time to death (transplantation censored) and time to death or transplant. RESULTS CPFE criteria were met in 29 of 365 patients with IPF (8%), with high agreement between radiologists (κ=0.74). Patients with CPFE had less fibrosis on HRCT scans and higher FVC, but greater oxygen requirements (P≤.01 for all comparisons). Findings were maintained with adjustment for fibrosis severity. Inhaled therapies for COPD were used by 53% of patients with CPFE. There was no significant difference in mortality comparing patients with CPFE and IPF to those with non-CPFE IPF (hazard ratio, 1.14; 95% CI, 0.61-2.13; P=.69). CONCLUSIONS CPFE was identified in 8% of patients with IPF and is a distinct, clinical phenotype with potential therapies that remain underutilized. Patients with CPFE and IPF and those with non-CPFE IPF have similar mortality.

Prevalence and prognosis of unclassifiable interstitial lung disease

The aim of this study was to determine the prevalence, characteristics and outcomes of patients with unclassifiable interstitial lung disease (ILD) and to develop a simple method of predicting disease behaviour. Unclassifiable ILD patients were identified from an ongoing longitudinal cohort. Unclassifiable ILD was diagnosed after a multidisciplinary review did not secure a specific ILD diagnosis. Clinical characteristics and outcomes were compared with idiopathic pulmonary fibrosis (IPF) and non-IPF ILDs. Independent predictors of mortality were determined using Cox proportional-hazards analysis to identify subgroups with distinct disease behaviour. Unclassifiable ILD was diagnosed in 10% of the ILD cohort (132 out of 1370 patients). The most common reason for being unclassifiable was missing histopathological assessment due to a high risk of surgical lung biopsy. Demographic and physiological features of unclassifiable ILD were intermediate between IPF and non-IPF disease controls. Unclassifiable ILD had longer survival rates when compared to IPF on adjusted analysis (hazard ratio 0.62, p = 0.04) and similar survival compared to non-IPF ILDs (hazard ratio 1.54, p = 0.12). Independent predictors of survival in unclassifiable ILD included diffusion capacity of the lung for carbon monoxide (p = 0.001) and a radiological fibrosis score (p = 0.02). Unclassifiable ILD represents approximately 10% of ILD cases and has a heterogeneous clinical course, which can be predicted using clinical and radiological variables. Unclassifiable ILD has a heterogeneous clinical course that can be predicted using clinical and radiological variables http://ow.ly/mdjwg

Predicting Survival Across Chronic Interstitial Lung Disease: The ILD-GAP Model

BACKGROUND Risk prediction is challenging in chronic interstitial lung disease (ILD) because of heterogeneity in disease-specific and patient-specific variables. Our objective was to determine whether mortality is accurately predicted in patients with chronic ILD using the GAP model, a clinical prediction model based on sex, age, and lung physiology, that was previously validated in patients with idiopathic pulmonary fibrosis. METHODS Patients with idiopathic pulmonary fibrosis (n=307), chronic hypersensitivity pneumonitis (n=206), connective tissue disease-associated ILD (n=281), idiopathic nonspecific interstitial pneumonia (n=45), or unclassifiable ILD (n=173) were selected from an ongoing database (N=1,012). Performance of the previously validated GAP model was compared with novel prediction models in each ILD subtype and the combined cohort. Patients with follow-up pulmonary function data were used for longitudinal model validation. RESULTS The GAP model had good performance in all ILD subtypes (c-index, 74.6 in the combined cohort), which was maintained at all stages of disease severity and during follow-up evaluation. The GAP model had similar performance compared with alternative prediction models. A modified ILD-GAP Index was developed for application across all ILD subtypes to provide disease-specific survival estimates using a single risk prediction model. This was done by adding a disease subtype variable that accounted for better adjusted survival in connective tissue disease-associated ILD, chronic hypersensitivity pneumonitis, and idiopathic nonspecific interstitial pneumonia. CONCLUSION The GAP model accurately predicts risk of death in chronic ILD. The ILD-GAP model accurately predicts mortality in major chronic ILD subtypes and at all stages of disease.

Relative versus absolute change in forced vital capacity in idiopathic pulmonary fibrosis

Background Decline in forced vital capacity (FVC) over time reliably predicts mortality in patients with idiopathic pulmonary fibrosis. The use of this measure in clinical practice is recommended by current evidence-based guidelines. It is unknown if the method of calculating decline in FVC (relative vs absolute change) impacts its frequency or its ability to predict mortality. Methods Patients with idiopathic pulmonary fibrosis from two prospective cohorts were included if they had a baseline and 12-month follow-up FVC. A ≥10% decline in FVC from baseline was calculated in two ways: a relative decline of 10% (eg, from 60% predicted to 54% predicted) and an absolute decline of 10% (eg, from 60% predicted to 50% predicted). The frequency of a ≥10% decline in FVC and its ability to predict 2-year transplant-free survival were compared between these two methods. Declines in FVC of ≥5% and ≥15% were similarly compared. Analyses were performed unadjusted and adjusted for age, gender, use of oxygen, baseline FVC and baseline diffusion capacity for carbon monoxide. Results The frequency of any given FVC decline was significantly greater using the relative change in FVC method. For ≥10% decline, both methods predicted 2-year transplant-free survival with similar accuracy, and remained significant predictors after adjusting for baseline characteristics. The absolute change method appeared more predictive for ≥5% decline. Conclusions Using the relative change in FVC maximises the chance of identifying a ≥10% decline in FVC without sacrificing prognostic accuracy. This may not hold true for ≥5% decline in FVC. These findings have important implications for clinical practice and the design of clinical trials.

Radiographic Fibrosis Score Predicts Survival in Hypersensitivity Pneumonitis

BACKGROUND It is unknown if the radiographic fibrosis score predicts mortality in persistent hypersensitivity pneumonitis (HP) and if survival is similar to that observed in idiopathic pulmonary fibrosis (IPF) when adjusting for the extent of radiographic fibrosis. METHODS We reviewed records from 177 patients with HP and 224 patients with IPF whose diagnoses were established by multidisciplinary consensus. Two thoracic radiologists scored high-resolution CT (HRCT) scan lung images. Independent predictors of transplant-free survival were determined using a Cox proportional hazards analysis. Kaplan-Meier survival curves were constructed, stratified by disease as well as fibrosis score. RESULTS HRCT scan fibrosis score and radiographic reticulation independently predicted time to death or lung transplantation. Clinical predictors included a history of cigarette smoking, auscultatory crackles on lung examination, baseline FVC, and FEV1/FVC ratio. The majority of HP deaths occurred in patients with both radiographic reticulation and auscultatory crackles on examination, compared with patients with only one of these manifestations (P < .0001). Patients with IPF had worse survival than those with HP at any given degree of radiographic fibrosis (hazard ratio 2.31; P < .01). CONCLUSIONS Survival in patients with HP was superior to that of those with IPF with similar degrees of radiographic fibrosis. The combination of auscultatory crackles and radiographic reticulation identified patients with HP who had a particularly poor outcome.

Cough predicts prognosis in idiopathic pulmonary fibrosis

Background and objective:  The clinical associations and prognostic value of cough in IPF have not been adequately described. The objective of this study was to describe the characteristics and prognostic value of cough in IPF.

Depression and Functional Status Are Strongly Associated With Dyspnea in Interstitial Lung Disease

BACKGROUND Little is understood about the characteristics of dyspnea in patients with interstitial lung disease (ILD), and its severity is likely influenced by multiple factors. Depression and functional status are known to influence dyspnea in patients with COPD. The aim of this study was to determine the relationship of dyspnea with clinical parameters, including depression and functional status, in patients with ILD. METHODS Dyspnea was measured with the Baseline Dyspnea Index and the University of California San Diego Shortness of Breath Questionnaire. Clinical parameters were recorded. Regression analysis was performed to determine independent correlates of dyspnea. RESULTS Fifty-two subjects were enrolled. The two dyspnea scales were strongly correlated (r=-0.79; P<.00005). The mean levels of dyspnea were 6.5 and 41.0, representing a moderate degree of dyspnea. Clinically meaningful depressive symptoms were found in 23% of subjects. Independent correlates of dyspnea severity for each dyspnea scale were depression score (P=.002 and P<.0005), 4-m walk time (P=.001 and P=.06), FVC (P=.07 and P=.004), and diffusing capacity of the lung for carbon monoxide (P=.007). BMI had borderline significant association with the Baseline Dyspnea Index (P=.10). CONCLUSIONS In patients with ILD, dyspnea is associated with depression score, functional status, and pulmonary function. These results suggest that attention to depression and functional status is important in these patients and that treatment directed at these comorbidities may improve dyspnea and quality of life. TRIAL REGISTRY ClinicalTrials.gov; No.: NCT00611182 ; URL: www. clinicaltrials.gov.

Acute exacerbation of idiopathic pulmonary fibrosis: shifting the paradigm

The goal of this review is to summarise the clinical features, management, and prognosis of acute exacerbations of idiopathic pulmonary fibrosis (AE-IPF). AE-IPF has previously been defined based on clinical and radiological features that include the subacute onset of dyspnoea, bilateral ground glass changes on chest high-resolution computed tomography, and the absence of an identifiable aetiology. The annual incidence of AE-IPF is typically reported at 5–15%, but is less common in mild disease. Features of diffuse alveolar damage are present when a biopsy is performed. Idiopathic pulmonary fibrosis (IPF) patients with acute respiratory worsening are often initially treated with high dose corticosteroids and antimicrobials; however, there are no clear data to support these therapies, and the short-term mortality of AE-IPF is ∼50%. Recent studies have shown that the features and prognosis of AE-IPF are similar to other causes of acute respiratory worsening, including infection, aspiration, air pollution and mechanical injury to the alveolar epithelium. Based on this emerging evidence, we propose a novel approach to the classification of acute respiratory worsening events in patients with IPF that focuses on clinical and radiological findings consistent with an underlying pathobiology of diffuse alveolar damage. A review summarising the features, management, and prognosis of acute exacerbations of idiopathic pulmonary fibrosis http://ow.ly/Oer3e