Unclassifiable Interstitial Lung Disease Research Articles

Costs of Workplace Productivity Loss in Patients With Fibrotic Interstitial Lung Disease

Fibrotic interstitial lung diseases (ILDs) are highly morbid chronic disorders that frequently occur in working age individuals. The goal of this study was to determine workplace productivity loss, its determinants, and its estimated costs in patients with fibrotic ILD. Patients with idiopathic pulmonary fibrosis, chronic hypersensitivity pneumonitis, idiopathic nonspecific interstitial pneumonia, or unclassifiable ILD were identified from the six-center Canadian Registry for Pulmonary Fibrosis (CARE-PF). The Work Productivity and Activity Impairment questionnaire was used to determine health-related productivity loss. Independent predictors of low workplace productivity were identified by using multivariate regression. Patient data were compared with Canadian population census data. The average productivity loss (hours per week) and the individual's hourly wage were used to estimate the costs of productivity loss. Of 650 eligible patients, 148 (23%) were employed. Productivity loss was reported by 55%of employed patients with an average productivity loss of 7.8 ± 0.9h per week (2.3 ± 0.6h per week related to absenteeism and 5.5 ± 0.6h per week related to presenteeism). Employment among patients with ILD aged 25 to 54 years was 23%lower than the age- and sex-matched general Canadian population (60%vs83%; P< .001). Employment among patients with ILD aged≥ 55 years was 18%lower than in the age- and sex-matched population (20%vs38%; P< .001). Dyspnea and cough were independent predictors of workplace productivity loss. Estimated annual costs of productivity loss were 11,610 Canadian dollars per employee with ILD. Workplace productivity loss is common in fibrotic ILD, strongly correlated with symptom severity, and associated with significant cost.

Update in the diagnostic approach to fibrotic interstitial lung disease

Fibrotic interstitial lung disease (ILD) is increasingly recognized as an important cause of chronic pulmonary disease. Although ILDs can be challenging to diagnose and manage, there have been a number of recent developments aimed at improving the accuracy of establishing a confident underlying diagnosis. This Clinical Respiratory Review summarizes recent developments in the diagnostic approach to some of the most common forms of fibrotic ILD, including idiopathic pulmonary fibrosis, chronic hypersensitivity pneumonitis, idiopathic nonspecific interstitial pneumonia, and unclassifiable ILD. In this review, we have summarized international consensus guidelines, working group reports, and other clinically relevant and highly impactful publications.

Combined pulmonary fibrosis and emphysema as a clinicoradiologic entity: Characterization of presenting lung fibrosis and implications for survival.

The prevalence of classifiable and unclassifiable causes of lung fibrosis and its implications for survival are mostly unknown in combined pulmonary fibrosis and emphysema (CPFE). Patients with >10% involvement of both emphysema and lung fibrosis seen over 11 years at our institution were reviewed independently by expert radiologists for fibrotic and emphysematous findings and overall fibrotic CT pattern. Underlying interstitial lung disease (ILD) diagnoses and baseline demographic and clinical characteristics were collated and assessed for predictors of comparative survival. In this retrospective cohort, 179 CPFE patients were identified and categorized as 58 usual interstitial pneumonia/idiopathic pulmonary fibrosis (UIP/IPF) (32%), 42 secondary ILD (23%), and 79 unclassifiable ILD (44%). The most prevalent (47%) radiologic pattern was 'unclassifiable', followed by 'consistent' and 'possible' UIP pattern in 38%. Adjusted predictors of mortality for the cohort as a whole included age (HR 1.03[1.01-1.06], P = 0.002), percent predicted diffusing capacity for carbon monoxide (unit HR 0.97 [0.96-0.99], P = 0.001), honeycombing (HR 1.58 [1.02-2.43], P = 0.04), and right ventricular dysfunction (HR 2.28 [1.39-3.97], P = 0.002). Survival was similar between CPFE with secondary ILD and CPFE with UIP/IPF, while CPFE with unclassifiable ILD had better comparative survival (Log rank = 0.026). Our findings suggest only about a third of CPFE patients represent suspected UIP/IPF; the majority were clinically and radiologically unclassifiable ILD whose survival was comparatively better. Identifiable or secondary causes of lung fibrosis in CPFE occurred in about a fifth of presenting patients.

Unclassifiable interstitial lung disease: from phenotyping to possible treatments.

Accurate diagnosis of interstitial lung diseases (ILDs) can be challenging, and a substantial percentage of ILD patients remain unclassifiable even after thorough assessment by an experienced multidisciplinary team. In this review, we summarize the recent literature on the definition, prevalence, diagnosis, treatment, and prognosis of unclassifiable ILD, and also discuss important current issues and provide future perspectives on the classification of ILD. Approximately 12% of patients with ILD are considered unclassifiable, with large variability across previous studies that is in part secondary to inconsistent definitions of unclassifiable ILD and other ILD subtypes. A recent International Working Group suggested that unclassifiable ILD should be defined by the absence of a leading diagnosis that is considered more likely than not after multidisciplinary discussion of all available information. Clinical features and outcomes of unclassifiable ILD are intermediate between idiopathic pulmonary fibrosis and nonidiopathic pulmonary fibrosis ILD cohorts, and choices for pharmacotherapy should be considered on a case-by-case basis. Recent studies have provided additional data on the clinical features and prognosis of unclassifiable ILD, but also highlight the many uncertainties that still exist in ILD diagnosis and classification. New tools are needed to more accurately characterize patients with unclassifiable ILD.

Pirfenidone in patients with unclassifiable progressive fibrosing interstitial lung disease: design of a double-blind, randomised, placebo-controlled phase II trial

IntroductionDespite extensive multidisciplinary team (MDT) assessment, some patients have interstitial lung disease (ILD) that is considered unclassifiable (uILD), for which there are currently no approved treatments. This study will assess...

Heterogeneity in Unclassifiable Interstitial Lung Disease. A Systematic Review and Meta-Analysis.

Accurate diagnosis of interstitial lung disease is necessary to identify the most appropriate management strategy and to inform prognosis. Many patients cannot be provided a confident diagnosis, despite an exhaustive search for potential etiologies and review in a multidisciplinary conference, and are consequently labeled with unclassifiable interstitial lung disease. To systematically review and meta-analyze previous studies reporting on the diagnostic criteria, prevalence, clinical features, and outcome of unclassifiable interstitial lung disease. MEDLINE, Embase, and the Cochrane Central Register of Controlled Trials databases were systematically searched for all studies related to unclassifiable interstitial lung disease published before September 1, 2017. Two authors independently screened each citation for eligibility criteria, serially reviewing the title, abstract, and full-text manuscript, and then abstracted data pertaining to the study objectives from eligible studies. Articles were stratified by risk of selection bias, whether the publication stated that patients were reviewed in a multidisciplinary discussion, and by the frequency of surgical lung biopsy. Meta-analyses and meta-regression were performed to calculate the pooled prevalence of unclassifiable interstitial lung disease within an interstitial lung disease population and within specific subgroups to identify reasons for across-study heterogeneity. The search identified 10,130 unique citations, 313 articles underwent full-text review, and eligibility criteria were met in 88 articles. Twenty-two studies were deemed low risk of selection bias, including 1,060 patients with unclassifiable interstitial lung disease from a total of 10,174 patients with interstitial lung disease. The terminology and definition of unclassifiable interstitial lung disease varied substantially across publications, with inconsistent diagnostic criteria and evaluation processes. The prevalence of unclassifiable interstitial lung disease was 11.9% (95% confidence interval, 8.5-15.6%), with lower prevalence in centers that reported use of a formal multidisciplinary discussion of cases (9.5% vs. 14.5%). Four articles reported survival of unclassifiable interstitial lung disease, with 1-year, 2-year, and 5-year survival of 84% to 89%, 70% to 76%, and 46% to 70%, respectively. This systematic review and meta-analysis shows that unclassifiable interstitial lung disease is common but has substantial heterogeneity and inconsistent definitions across interstitial lung disease cohorts. These findings highlight important limitations in multicenter studies of fibrotic interstitial lung disease and the need for a standardized approach to interstitial lung disease diagnostic classification.

Diagnostic Ability of a Dynamic Multidisciplinary Discussion in Interstitial Lung Diseases: A Retrospective Observational Study of 938 Cases

The advice of a dynamic multidisciplinary discussion (MDD) is believed to be important in the diagnosis of interstitial lung diseases (ILDs). However, to what extent MDD diagnoses differ from the preliminary diagnoses before formal workup and MDD (preMDD diagnoses) is still insufficiently studied. We compared preMDD and MDD diagnoses in patients discussed at the Leuven University Hospitals MDDs between January 2005 and December2015. Of 938 consecutive patients discussed in an MDD, 755 (80.5%) received a specific diagnosis. From the 183 patients with unclassifiable ILD, 150 patients (16.0%) received suggestions concerning further investigations to establish a definite diagnosis. In 191 patients (41.9%of patients with a preMDD diagnosis), the MDD changed the diagnosis. In 384 patients (79.5%of patients without preMDD diagnosis), MDD provided a diagnosis when the referring physician did not. MDD diagnosis showed a trend toward better prognostic discrimination between idiopathic pulmonary fibrosis and other ILDs compared with preMDD diagnosis (Harrell C-index, 0.666 vs0.631; P= .08), which was particularly clear in patients with discordant MDD and preMDD diagnoses (hazard ratio, 2.68 vs0.84; P= .012 vs.768). The MDD provided a definite diagnosis in 80.5%of presented cases, suggesting further investigations in almost all others. Given the high number of patients without preMDD diagnosis, the rate of change in preMDD diagnoses (41.9%of patients with a preMDD diagnosis) probably is an underestimation. The better prognostic discrimination among ILDs by using MDD indicates the added value of MDD in ILD.

Unclassifiable interstitial lung disease: a pathologist's perspective

Classifying pulmonary fibrotic disease into various diagnostic categories provides the clinician with expectations for both prognosis and proper treatment. Despite years of experience with histological, radiological and clinical guidelines, a group of patients remains with unclassifiable interstitial lung disease. In this article, the possible barriers to classification will be explored, and some strategies will be discussed to aid in overcoming these barriers.

Outcomes and Mortality Prediction Model of Critically Ill Adults With Acute Respiratory Failure and Interstitial Lung Disease

We aimed to examine short- and long-term mortality in a mixed population of patients with interstitial lung disease (ILD) with acute respiratory failure, and to identify those at lower vshigher risk of in-hospital death. We conducted a single-center retrospective cohort study of 126 consecutive adults with ILD admitted to an ICU for respiratory failure at a tertiary care hospital between 2010 and 2014 and who did not undergo lung transplantation during their hospitalization. We examined associations of ICU-day 1 characteristics with in-hospital and 1-year mortality, using Poisson regression, and examined survival using Kaplan-Meier curves. We created a risk score for in-hospital mortality, using a model developed with penalized regression. In-hospital mortality was 66%, and 1-year mortality was 80%. Those with connective tissue disease-related ILD had better short-term and long-term mortality compared with unclassifiable ILD (adjusted relative risk, 0.6; 95%CI, 0.3-0.9; and relative risk, 0.6; 95%CI, 0.4-0.9, respectively). Our prediction model includes male sex, interstitial pulmonary fibrosis diagnosis, use of invasive mechanical ventilation and/or extracorporeal life support, no ambulation within 24h of ICU admission, BMI, and Simplified Acute Physiology Score-II. The optimism-corrected C-statistic was 0.73, and model calibration was excellent (P= .99). In-hospital mortality rates for the low-, moderate-, and high-risk groups were 33%, 65%, and 96%, respectively. We created a risk score that classifies patients with ILD with acute respiratory failure from low to high risk for in-hospital mortality. The score could aid providers in counseling these patients and their families.

Spontaneous Pneumomediastinum in Connective Tissue Diseases

SESSION TITLE: Systemic Disease and Pulmonary Manifestations SESSION TYPE: Original Investigation Poster PRESENTED ON: Wednesday, November 1, 2017 at 01:30 PM - 02:30 PM PURPOSE: Spontaneous pneumomediastinum (SP) is an uncommon manifestation of connective tissue diseases (CTD) but has been associated with the diagnosis of dermatomyositis/polymyositis (DM/PM). We aimed to explore this relationship by identifying consecutive adult patients with CTD and SP and analyzing the presenting features and clinical course associated with this complication. METHODS: Using a computer-assisted search, we retrospectively identified and reviewed the medical records of all CTD patients diagnosed with SP between January 1997 and December 2016. We extracted data regarding demographics, clinical manifestations and treatment of the underlying CTD. We also gathered information regarding clinical-radiological presentation and treatment of SP, and its outcome. Chest CT studies were reviewed to investigate the presence and describe the pattern of the underlying interstitial lung disease (ILD). RESULTS: We identified 27 patients affected by CTD who developed SP (8 cases of DM/PM, 6 rheumatoid arthritis, 6 systemic sclerosis, 4 overlap syndromes, 2 systemic lupus erythematosus and 1 unclassifiable CTD). Median age at SP presentation was 53 (range 18-82) years and 59% were women. Sixty-two per cent of patients were never smokers, 27% were former smokers and 11% were current smokers. SP occurred before the diagnosis of CTD in 3 patients while SP led to the diagnosis of CTD in 5 additional patients; remaining 19 patients (70%) had a known CTD including associated ILD in all but one patient. SP-related symptoms were present in 58% of patients and included dyspnea (46%), followed by chest pain (27%) and cough (12%); 42% were asymptomatic. The precipitating factors included pulmonary function testing in 31% of patients, severe coughing due to exacerbation or respiratory infection in 15%, vomiting in 8%, air travel in 8%; in 46% no potential precipitating factors were identified. Seventy-eight per cent of patients were on immunosuppressant therapy at the time of SP onset. The initial diagnosis of SP was achieved by chest radiography in 20% of cases, chest CT in 64% and CT pulmonary angiography in 16%. Concomitant pneumothorax was present in 4 cases (17%). Only 2 cases (8%) of SP occurred in the absence of CTD-associated interstitial lung disease (ILD). The most common ILD pattern on chest CT was NSIP in 45%, followed by BOOP superimposed on NSIP in 18%, unclassifiable ILD in 23%, and possible UIP in 5%. SP was treated with observation alone in 23 cases (88%). Eleven patients (42%) were hospitalized. Chest tube drainage was instituted in one of 4 patients with pneumothorax. The median hospital stay was 11 (range 1-20) days. There were no deaths attributable to SP nor were there any relapses of SP in a median follow up of 14 (range 0-183) months. The cumulative survival at 1 and 2 years was 56% and 44% respectively. CONCLUSIONS: SP is an uncommon manifestation of CTD related ILD but sometimes it can lead to the diagnosis of CTD. SP is associated with a relatively benign course in patients with CTD. CLINICAL IMPLICATIONS: SP is an uncommon manifestation seen in patients with CTD and can usually be managed conservatively with observation alone. DISCLOSURE: The following authors have nothing to disclose: Federica De Giacomi, Misbah Baqir, Christian W. Cox, Jay Ryu No Product/Research Disclosure Information

Prognostic factors and outcomes in Japanese lung transplant candidates with interstitial lung disease.

ObjectiveYoung patients with advanced interstitial lung disease (ILD) are potential candidates for cadaveric lung transplantation. This study aimed to examine clinical features, outcomes, and prognostic factors in Japanese ILD patients awaiting lung transplantation.MethodsWe investigated the clinical features and outcomes of 77 consecutive candidates with ILD who were referred to Kyoto University Hospital and subsequently actively listed for lung transplant in the Japan Organ Transplant Network between 2010 and 2014.ResultsOf the 77 candidates, 33 had idiopathic pulmonary fibrosis (IPF) and 15 had unclassifiable ILD. During the observational period, 23 patients (30%) received lung transplantations and 49 patients (64%) died before transplantation. Of the 33 patients with IPF, 13 (39%) had a family history of ILD and 13 (39%) had an “inconsistent with usual interstitial pneumonia pattern” on high-resolution computed tomography (HRCT). The median survival time from registration was 16.7 months, and mortality was similar among patients with IPF, unclassifiable ILD, and other ILDs. Using a multivariate stepwise Cox proportional hazards model, 6-min walking distance was shown to be an independent prognostic factor in candidates with ILD (per 10 m, hazard ratio (HR): 0.97; 95% confidence interval (CI): 0.95–0.99, p<0.01), while lower body mass index (HR: 0.83; 95% CI: 0.72–0.95, p < 0.01) independently contributed to mortality in patients with IPF.ConclusionsJapanese patients with ILD awaiting transplantation had very poor outcomes regardless of their specific diagnosis. A substantial percentage of IPF patients had an atypical HRCT pattern. 6-min walking distance in ILD patients and body mass index in IPF patients were independent predictors of mortality.

Unclassifiable-interstitial lung disease: Outcome prediction using CT and functional indices.

Unclassifiable-interstitial lung disease (uILD) represents a heterogeneous collection of pathologies encompassing those fibrosing lung diseases which do not fulfill current diagnostic criteria. We evaluated baseline and longitudinal functional and CT (visual and quantitative computer [CALIPER] analysis) variables to identify outcome predictors in uILD. Consecutive patients with uILD on multidisciplinary review (n=95) had baseline functional (FVC, DLco, CPI [composite physiologic index]) and CT features (visual evaluation: CT pattern, fibrosis extent, honeycombing presence, traction bronchiectasis severity, pulmonary artery (PA) diameter; CALIPER evaluation: fibrosis extent, pulmonary vessel volume (PVV)) examined in univariate and multivariate Cox regression models. Change in functional and CT variables were examined in a patient subset (n=37), to identify indicators of outcome. On univariate analysis, CPI was the most powerful functional predictor of mortality (p<0.0001). Visual traction bronchiectasis (p<0.0001), PA diameter (p<0.0001) and honeycombing presence (p=0.0001) and CALIPER PVV (p=0.0003) were the strongest CT outcome predictors. On multivariate analysis of baseline indices, traction bronchiectasis (p=0.003), PA diameter (p=0.003) and CPI (p=0.0001) independently predicted mortality. Colinearity with functional indices precluded the evaluation of CALIPER PVV in multivariate models. On evaluation of longitudinal variables, increasing CALIPER fibrosis extent was the strongest outcome predictor, and remained so following adjustment for baseline disease severity, and when FVC declines were marginal. In uILD patients, CPI, traction bronchiectasis severity and PA diameter independently predicted outcome at baseline. Increasing fibrosis extent measured by CALIPER was the most powerful index of outcome regardless of baseline disease severity and strongly predicted outcome in patients with marginal FVC declines.

Year in review 2016: Interstitial lung disease, pulmonary vascular disease, pulmonary function, paediatric lung disease, cystic fibrosis and sleep.

Year in review 2016: Interstitial lung disease, pulmonary vascular disease, pulmonary function, paediatric lung disease, cystic fibrosis and sleep.

Prevalence, characteristics, and outcomes of patients with unclassifiable interstitial lung disease

Prevalence, characteristics, and outcomes of patients with unclassifiable interstitial lung disease

Interstitial Lung Disease in the Elderly

Despite the relationship between idiopathic pulmonary fibrosis (IPF) and advancing age, little is known about the epidemiology of interstitial lung disease (ILD) in the elderly. We describe the diagnoses, clinical characteristics, and outcomes of patients who were elderly at the time of ILD diagnosis. Among subjects from a prospective cohort study of ILD, elderly was defined as age≥ 70 years. Diagnoses were derived from a multidisciplinary review. Differences between elderly and nonelderly groups were determined using the χ2 test and analysis of variance. Of the 327 subjects enrolled, 80 (24%) were elderly. The majority of elderly subjects were white men. The most common diagnoses were unclassifiable ILD (45%), IPF (34%), connective tissue disease (CTD)-ILD (11%), and hypersensitivity pneumonitis (8%). Most elderly subjects (74%) with unclassifiable ILD had an imaging pattern inconsistent with usual interstitial pneumonia (UIP). There were no significant differences in pulmonary function or 3-year mortality between nonelderly and elderly subjects combined or in a subgroup analysis of those with IPF. Although IPF was the single most common diagnosis, the majority of elderly subjects had non-IPF ILD. Our findings highlight the need for every patient with new-onset ILD, regardless of age, to be surveyed for exposures and findings of CTD. Unclassifiable ILD was common among the elderly, but for most, the radiographic pattern was inconsistent with UIP. Although the effect of ILD may be more pronounced in the elderly due to reduced global functionality, ILD was not more severe or aggressive in this group.

Unclassifiable interstitial lung diseases: Clinical characteristics and survival.

Unclassifiable disease in chronic interstitial lung disease (ILD) is a common and challenging problem but has been insufficiently studied. The 2013 update of the international multidisciplinary classification of the idiopathic interstitial pneumonias presented a classification based on observed disease behaviour with the purpose of providing guidance to clinicians in the management of these patients. The aim of this study was to apply the new disease behaviour classification (DBC) and the previously validated ILD-gender age physiology (GAP) score to a cohort of unclassifiable ILD patients and to assess the prognostic value of these two composite approaches. Unclassifiable ILD patients were identified from the population-based ILD registry at Aarhus University Hospital, Denmark, that includes all ILD patients diagnosed at the department from 2003 to 2009. The DBC was assessed retrospectively based on clinical presentation and diagnostic examinations at presentation and short-term follow-up. Unclassifiable ILD was diagnosed in 24% of the cohort (105 of 431). Survival in unclassifiable ILD was intermediate between idiopathic pulmonary fibrosis (IPF) and non-IPF controls (idiopathic non-specific interstitial pneumonia (NSIP), hypersensitivity pneumonitis and connective tissue disease-associated ILD). The DBC and the ILD-GAP index were strong individual predictors of outcome in a dichotomized regression model (hazard ratio (HR): 6.3 (95% CI: 1.8-21.2) for the DBC and HR: 6.7 (95% CI: 2.2-20.0) for ILD-GAP). Both approaches remained significant in a common regression model (HR: 4.5 (95% CI: 1.3-15.7) for the DBC and HR: 5.1 (95% CI: 1.3-15.7) for ILD-GAP). The DBC approach showed strong prognostic value in unclassifiable ILD. The DBC and the ILD-GAP were complementary predictors of outcome in unclassifiable ILD.

Unclassifiable interstitial lung disease: A review.

Accurate classification of interstitial lung disease (ILD) requires a multidisciplinary approach that incorporates input from an experienced respirologist, chest radiologist and lung pathologist. Despite a thorough multidisciplinary evaluation, up to 15% of ILD patients have unclassifiable ILD and cannot be given a specific diagnosis. The objectives of this review are to discuss the definition and features of unclassifiable ILD, identify the barriers to ILD classification and outline an approach to management of unclassifiable ILD. Several recent studies have described the characteristics of these patients; however, there are inconsistencies in the definition and terminology of unclassifiable ILD due to limited research in this population. Additional studies are required to determine the appropriate evaluation and management of patients with unclassifiable ILD.

Unclassifiable interstitial lung disease: an unresolved diagnostic dilemma

Interstitial lung disease (ILD) classification requires a multidisciplinary review that includes input from an ILD clinician, chest radiologist, and lung pathologist. We report a case of ILD that remained unclassifiable due to discordant clinical, radiological, and pathological findings despite a thorough evaluation that included examination of explanted lung tissue. This case demonstrates that ILD can remain unclassifiable even with a complete evaluation and illustrates one approach to the management of such patients.

Broader criteria of undifferentiated connective tissue disease in idiopathic interstitial pneumonias

Kinder et al. proposed a broader definition of undifferentiated connective tissue disease (UCTD) and reported that the entity of nonspecific interstitial pneumonia (NSIP) is a lung manifestation of this more broadly defined UCTD. However, a retrospective study did not support their findings and its clinical significance remains unclear. We prospectively evaluated the significance of this broadly defined UCTD in idiopathic interstitial pneumonias (IIPs) in consecutive patients with surgical lung biopsy. Patients were evaluated with a symptoms check list and underwent comprehensive serologic testing as screening for UCTD. Clinical characteristics, high-resolution CT images, lung biopsy specimens, serial FVC change, and survival were analyzed. Among 76 patients with IIPs, 24 patients (32%) fulfilled the UCTD criteria. Diagnosis of 24 patients with UCTD was usual interstitial pneumonia in 12 (50%), NSIP in 7 (29%), and unclassifiable interstitial lung disease (ILD) in 5 (21%). The diagnosis of 52 patients who did not have UCTD was idiopathic pulmonary fibrosis in 27 (52%), NSIP in 11 (21%), unclassifiable ILD in 13 (25%) and cryptogenic organizing pneumonia in 1 (2%). One-year and two-year FVC changes showed no significant difference between UCTD and non-UCTD, however, significant differences in FVC change were observed among histopathological diagnoses both in UCTD and in non-UCTD. In multivariate survival analysis, %FVC and histopathological UIP pattern were independent predictors for survival but UCTD diagnosis was not. A diagnosis of UCTD was not useful in discriminating NSIP or in predicting disease progression and prognosis in our cohort of IIPs. Histopathological UIP pattern was an independent predictor for mortality irrespective of a diagnosis of UCTD.

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

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. 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. 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. 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.