A double-blind, placebo-controlled, randomized withdrawal trial of sarilumab for the treatment of glucocorticoid-dependent sarcoidosis.

OBJECTIVES: Effective steroid-sparing therapies for the treatment of sarcoidosis are lacking; interleukin-6 (IL-6) antagonists may reduce sarcoidosis disease activity. This study assessed the safety and efficacy of the IL-6 receptor antagonist, sarilumab, in subjects with glucocorticoid-dependent sarcoidosis. METHODS: This phase II, double-blind, placebo-controlled, randomized withdrawal trial enrolled 15 subjects with biopsy-proven sarcoidosis at Stanford University from November 2019 to September 2022. In Period 1, subjects were treated with open-label sarilumab 200mg subcutaneously every two weeks for 16 weeks, with predefined tapering of prednisone. Subjects who completed Period 1 without a sarcoidosis flare entered Period 2 and were randomized to continue sarilumab or to receive matching placebo for 12 weeks. Endpoints included flare-free survival, as well as changes in pulmonary function tests, chest imaging, patient reported outcomes, and laboratory values. RESULTS: Fifteen subjects were enrolled in the study (median age 57 years, 80% male, 73.3% White), and 10 subjects successfully completed Period 1. During Period 1, 4 of 15 subjects (26.7%) discontinued due to worsening of their sarcoidosis, and CT chest imaging worsened in 5 of 15 subjects (35.7%). During Period 2, 0 of 2 subjects in the sarilumab group and 1 of 8 subjects (12.5%) in the placebo group had a flare. Treatment with sarilumab 200 mg was generally well tolerated in subjects with sarcoidosis. CONCLUSION: In this double-blind, placebo-controlled, randomized withdrawal trial, a meaningful signal for improvement in subjects with sarcoidosis treated with sarilumab was not observed. Given the small numbers in this study, no definitive conclusions can be drawn. TRIAL REGISTRATION: ClinicalTrials.gov Identifier: NCT04008069.

Estimated impact of hepatitis C-positive lung donor utilization on US donor lung supply.

The availability of highly effective direct-acting antiviral agents (DAAs) for hepatitis C virus (HCV) infection has led to reports of safely transplanting HCV+ donor lungs into HCV- candidates. However, it remains unclear how the ability to use HCV+ donor lungs for lung transplant could affect the number of donor lungs available for transplant. Using Scientific Registry of Transplant Recipient data, we identified all deceased organ donors within the United States from March 1, 2015, to February 28, 2018, and stratified by HCV status. A donor prediction model for lung donation was derived and validated within HCV- donors and applied to HCV+ donors to estimate the number of acceptable HCV+ lung donors. Of 29 481 eligible donors, 2054 (7.0%) were HCV+ donors with 82 HCV+ donors' lungs being used for transplant during the study period. The prediction model for donor lung donation (specificity 92.6%, sensitivity 65.6%) estimated 248 HCV+ donors (75 nonviremic, 173 viremic) were acceptable for lung transplant during the study period, suggesting that 166 acceptable HCV+ lung donors were discarded. The ability to transplant lungs from HCV+ organ donors would lead to an estimated nationwide increase of at least 55 donor lungs per year, including 44 from HCV viremic donors.

Multiple listing in lung transplant candidates: A cohort study.

Lung transplant candidates can be waitlisted at more than one transplant center, a practice known as multiple listing. The factors associated with multiple listing and whether multiple listing modifies waitlist mortality or likelihood of lung transplant is unknown. US lung transplant waitlist candidates were identified as either single or multiple listed using data from the Scientific Registry of Transplant Recipients. Characteristics of single and multiple listed candidates were compared and multivariable logistic regression was used to estimate associations with multiple listing. Multiple listed candidates were matched to single listed candidates using a combination of exact and propensity score matching methods. Cox proportional hazard models were used to estimate the relationship of multiple listing on waitlist mortality and receiving a transplant. Multiple listing occurred in 2.3% of lung transplant waitlist candidates. Younger age, female gender, white race, short stature, high antibody sensitization, college or postcollege education, lower lung allocation score, and a cystic fibrosis diagnosis were independently associated with multiple listing. Multiple listing was associated with an increased likelihood of lung transplant (adjusted hazard ratio [aHR] 2.74, 95% CI 2.37 to 3.16) but was not associated with waitlist mortality (aHR 0.99, 95% CI 0.68 to 1.44).

Mechanical ventilation in idiopathic pulmonary fibrosis: a nationwide analysis of ventilator use, outcomes, and resource burden.

BACKGROUND: Idiopathic pulmonary fibrosis (IPF) is associated with increased risk of respiratory-related hospitalizations. Studies suggest mechanical ventilation (MV) use in IPF does not improve outcomes and guidelines recommend against its general use. Our objective was to investigate MV use and association with cost and mortality in IPF. METHODS: This retrospective study, using a nationwide sample, included claims with IPF (ICD-9-CM: 516.3) in 2009-2011 and principal respiratory disease diagnosis (ICD-9-CM: 460-519); excluding lung transplant. Regression models were used to determine predictors of MV and association with cost, LOS, and mortality. Domain analysis was used to account for use of subpopulation. Costs were adjusted to 2011. Data on patient severity not available. RESULTS: Twenty two thousand three hundred fifty non-transplant IPF patients were admitted with principal respiratory disease diagnosis: Mean age 70.0 (SD 13.9), 49.1% female, mean LOS 7.4 (SD 8.2). MV was used in 11.4% of patients with a non-significant decline over time. In regression models, MV was associated with an increased stay of 9.78 days (95% CI 8.38-11.18) and increased cost of $36,583 (95% CI $32,021-41,147). MV users had significantly increased mortality (OR 15.55, 95% CI 12.13-19.95) versus nonusers. CONCLUSIONS: Mechanical ventilation use has not significantly changed over time and is mostly used in younger patients and those admitted for non-IPF respiratory conditions. MV was associated with a 4-fold admission cost increase ($49,924 versus $11,742) and a 7-fold mortality increase (56% versus 7.5%), although patients who receive MV may differ from those who do not. Advances in treatment and decision aids are needed to improve outcomes in IPF.

Lung transplantation following death by drowning: a review of the current literature.

While multiple donor characteristics have been cited as ideal for lung transplantation, there are minimal widely accepted exclusion criteria. One criterion that many centers view with hesitation is death by drowning. However, recent literature suggests such donors may result in acceptable outcomes following transplantation. This review highlights a case of a patient who underwent a successful bilateral lung transplant from a donor following a drowning event. A review of the current literature is presented, concluding with a new proposed set of favorable donor criteria following death by drowning.

Increased resource use in lung transplant admissions in the lung allocation score era.

RATIONALE: In 2005, the lung allocation score (LAS) was implemented to prioritize organ allocation to minimize waiting-list mortality and maximize 1-year survival. It resulted in transplantation of older and sicker patients without changing 1-year survival. Its effect on resource use is unknown. OBJECTIVES: To determine changes in resource use over time in lung transplant admissions. METHODS: Solid organ transplant recipients were identified within the Nationwide Inpatient Sample (NIS) data from 2000 to 2011. Joinpoint regression methodology was performed to identify a time point of change in mean total hospital charges among lung transplant and other solid-organ transplant recipients. Two temporal lung transplant recipient cohorts identified by joinpoint regression were compared for baseline characteristics and resource use, including total charges for index hospitalization, charges per day, length of stay, discharge disposition, tracheostomy, and need for extracorporeal membrane oxygenation. MEASUREMENTS AND MAIN RESULTS: A significant point of increased total hospital charges occurred for lung transplant recipients in 2005, corresponding to LAS implementation, which was not seen in other solid-organ transplant recipients. Total transplant hospital charges increased by 40% in the post-LAS cohort ($569,942 [$53,229] vs. $407,489 [$28,360]) along with an increased median length of stay, daily charges, and discharge disposition other than to home. Post-LAS recipients also had higher post-transplant use of extracorporeal membrane oxygenation (odds ratio, 2.35; 95% confidence interval, 1.56-3.55) and higher incidence of tracheostomy (odds ratio, 1.52; 95% confidence interval, 1.22-1.89). CONCLUSIONS: LAS implementation is associated with a significant increase in resource use during index hospitalization for lung transplant.

Associations of Plasma Omega-3 Fatty Acids With Progression and Survival in Pulmonary Fibrosis.

BACKGROUND: Preclinical experiments suggest protective effects of omega-3 fatty acids and their metabolites in lung injury and fibrosis. Whether higher intake of omega-3 fatty acids is associated with disease progression and survival in humans with pulmonary fibrosis is unknown. RESEARCH QUESTION: What are the associations of plasma omega-3 fatty acid levels (a validated marker of omega-3 nutritional intake) with disease progression and transplant-free survival in pulmonary fibrosis? STUDY DESIGN AND METHODS: Omega-3 fatty acid levels were measured from plasma samples of patients with clinically diagnosed pulmonary fibrosis from the Pulmonary Fibrosis Foundation Patient Registry (n = 150), University of Virginia (n = 58), and University of Chicago (n = 101) cohorts. The N-3 index (docosahexaenoic acid + eicosapentaenoic acid) was the primary exposure variable of interest. Linear-mixed effects models with random intercept and slope were used to examine associations of plasma omega-3 fatty acid levels with changes in FVC and diffusing capacity for carbon monoxide over a period of 12 months. Cox proportional hazards models were used to examine transplant-free survival. Stratified analyses by telomere length were performed in the University of Chicago cohort. RESULTS: Most of the cohort were patients with idiopathic pulmonary fibrosis (88%) and male patients (74%). One-unit increment in log-transformed N-3 index plasma level was associated with a change in diffusing capacity for carbon monoxide of 1.43 mL/min/mm Hg per 12 months (95% CI, 0.46-2.41) and a hazard ratio for transplant-free survival of 0.44 (95% CI, 0.24-0.83). Cardiovascular disease history, smoking, and antifibrotic usage did not significantly modify associations. Omega-3 fatty acid levels were not significantly associated with changes in FVC. Higher eicosapentaenoic acid plasma levels were associated with longer transplant-free survival among University of Chicago participants with shorter telomere length (P value for interaction = .02). INTERPRETATION: Further research is needed to investigate underlying biological mechanisms and whether omega-3 fatty acids are a potential disease-modifying therapy.

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.

Factors associated with listing for lung transplantation in IPF patients: An analysis of the pulmonary fibrosis foundation registry.

Rationale and objectives: Lung transplantation is a potentially life-saving treatment option for patients with idiopathic pulmonary fibrosis (IPF); however, not all eligible candidates get referred and listed for transplantation. Amongst IPF patients within the Pulmonary Fibrosis Foundation Patient Registry (PFF-R), we sought to determine the proportion of patients who undergo lung transplant listing and the characteristics associated with transplant listing. Methods: An analysis of IPF patients with at least six months of follow-up data was performed. Patients with well-established contraindications to lung transplantation were excluded. Two complementary analyses were performed. The "prevalent" population included all patients with IPF at time of enrollment into the registry. The "incident severe" population included all patients with IPF who progressed to GAP Stage 3. Results: Of the 2003 patients in the PFF-R, 475 patients were included in the "prevalent" population. Of this group, only 42 (8.8%) were either listed for or underwent lung transplant. Univariable analysis of the "prevalent" population found age (per 10 year increase, OR 0.531, p = 0.0025), percent predicted FVC (OR 0.572, p=<0.0001), percent predicted DLCO (OR 0.606, p < 0.0001), 6-min walk distance (per 50 m, OR 0.831, p = 0.019), and oxygen use at rest (OR 5.157, p < 0.0001) were predictive of listing. On multivariable analysis, age (per 10 year increase, OR 0.558, p = 0.0088), percent predicted FVC (OR 0.728, p = 0.0161), and oxygen use at rest (OR 3.264, p = 0.0029) remained significant predictors for lung transplant listing. The "incident severe" group consisted of 176 patients (8.8%). 24 patients (13.6%) from this cohort were either listed for or received a transplant. Only age (per 10 year increase, OR 0.0286, p = 0.0465) was associated with transplant listing on univariable analysis in the Incident severe population. Conclusion: Only a small proportion of potentially eligible patients with IPF are listed for lung transplantation, even when seen at pulmonary fibrosis centers of excellence. Advanced age appears to be the primary factor associated with failure to be listed. Further refinement of future registry data is required to more clearly delineate exact reasons for low rates of listing.

Rituximab Versus Mycophenolate in the Treatment of Recalcitrant Connective Tissue Disease-Associated Interstitial Lung Disease.

OBJECTIVE: Interstitial lung disease (ILD) is a major cause of morbidity and mortality in connective tissue diseases (CTDs). We aimed to assess the effect of rituximab ± mycophenolate mofetil (MMF) compared with MMF on pulmonary function and prednisone dosage in patients with CTD-related ILD (CTD-ILD). METHODS: This retrospective study included 83 patients from Stanford and Centre Hospitalier de l'Universite de Montreal. Fifteen patients received rituximab ± MMF (rituximab group), and 68 patients received MMF only (control group). RESULTS: Median ILD duration at the start of treatment was longer in the rituximab group at 47 months (range: 4-170) versus 6.5 months (range: 0-164) in controls. Forced vital capacity (FVC) decreased by 3.0% (range: 11%-21%) after treatment in the rituximab group, whereas it increased by 2.0% (range: 14%-25%) in the control group (p = 0.025). Diffusing capacity of carbon monoxide (DLCO) decreased by 3.0% (range: 10%-12%) after treatment in the rituximab group, whereas it increased by 4.5% (range: 30%-36%) in the control group (p = 0.046). Mixed model analysis controlling for ILD duration, baseline DLCO, systemic sclerosis, pulmonary hypertension, and prednisone use showed no significant difference in FVC or DLCO between groups at 6 months or 1 year. The average daily prednisone dose score decreased after treatment in the rituximab group, whereas it remained unchanged in the control group (p = 0.017). CONCLUSION: Rituximab ± MMF did not significantly change pulmonary function compared with MMF alone, but it did result in a relative decrease in average daily prednisone dose in a population with recalcitrant CTD-ILD.

First lung and kidney multi-organ transplant following COVID-19 Infection.

As the world responds to the global crisis of the COVID-19 pandemic an increasing number of patients are experiencing increased morbidity as a result of multi-organ involvement. Of these, a small proportion will progress to end-stage lung disease, become dialysis dependent, or both. Herein, we describe the first reported case of a successful combined lung and kidney transplantation in a patient with COVID-19. Lung transplantation, isolated or combined with other organs, is feasible and should be considered for select patients impacted by this deadly disease.

Effect of broader geographic sharing of donor lungs on lung transplant waitlist outcomes.

BACKGROUND: The United States lung allocation system prioritizes allocation based on medical urgency and benefit but does not address a federal mandate for broader geographic organ sharing. It is unknown whether broader geographic sharing of donor lungs would improve lung transplant waitlist outcomes. METHODS: A discrete event microsimulation model simulated donor lung allocation according to different geographic lung-sharing policies, including the historic local donor service area (DSA)-based policy and hypothetical policies that prioritize candidates to donors within 500-mile or 1,000-mile geographic radii. Candidate waitlist mortality, number of transplants, and 1-year survival were compared across organ allocation policies. Waitlist mortality rates were further stratified by diagnosis, Lung Allocation Score (LAS) threshold, ABO blood type, and region. RESULTS: Under broader geographic lung sharing, the proportion of chronic obstructive pulmonary disease transplant recipients decreased, whereas the proportion of pulmonary fibrosis recipients increased. Waitlist mortality decreased with broader geographic lung sharing with a 21.3% decrease in waitlist mortality with 500-mile lung sharing and a 31.8% decrease in waitlist mortality with 1,000-mile lung sharing. The decrease in waitlist deaths occured across all U.S. geographic regions and was greatest in candidates with pulmonary fibrosis and/or high medical urgency. CONCLUSIONS: Broader geographic sharing of donor lungs could reduce waitlist mortality, particularly among pulmonary fibrosis and high-medical-urgency candidates.

Evaluation of integrin αvß6 cystine knot PET tracers to detect cancer and idiopathic pulmonary fibrosis.

Advances in precision molecular imaging promise to transform our ability to detect, diagnose and treat disease. Here, we describe the engineering and validation of a new cystine knot peptide (knottin) that selectively recognizes human integrin αvß6 with single-digit nanomolar affinity. We solve its 3D structure by NMR and x-ray crystallography and validate leads with 3 different radiolabels in pre-clinical models of cancer. We evaluate the lead tracer's safety, biodistribution and pharmacokinetics in healthy human volunteers, and show its ability to detect multiple cancers (pancreatic, cervical and lung) in patients at two study locations. Additionally, we demonstrate that the knottin PET tracers can also detect fibrotic lung disease in idiopathic pulmonary fibrosis patients. Our results indicate that these cystine knot PET tracers may have potential utility in multiple disease states that are associated with upregulation of integrin αvß6.

Racial and ethnic disparities in lung transplant listing and waitlist outcomes.

BACKGROUND: The United States lung transplant registry data demonstrate differences in adult waitlist mortality by race/ethnicity. It is unknown whether these differences persist after risk adjustment or occur secondary to disparities in disease severity at the time of listing. METHODS: Adult lung transplant waitlist candidates between May 4, 2005 and March 5, 2015 were identified and compared by non-Hispanic white (NHW), non-Hispanic black (NHB), Hispanic and Asian race/ethnicity. A competing risk proportional hazards model was used to assess the association of race/ethnicity with the unadjusted and adjusted risk of waitlist death or removal for too sick, transplant, or removal for other reason. Disease illness severity at transplant listing was compared by race/ethnicity. RESULTS: There were 20,684 lung transplant candidates identified (82% NHW, 9% NHB, 6% Hispanic, 2% Asian and 1% other). Non-white candidates had higher unadjusted waitlist mortality, which was fully mitigated by adjusting for other risk factors (NHB: hazard ratio [HR] 1.05, 95% confidence interval [CI] 0.93 to 1.18; Hispanic: HR 1.02, 95% CI 0.99 to 1.18; Asian: HR 0.90, 95% CI 0.70 to 1.16). Adjusted waitlist access to transplant was lower in non-white candidates (NHB: HR 0.88, 95% CI 0.83 to 0.94; Hispanic: HR 0.87, 95% CI 0.81 to 0.94; Asian: HR 0.83, 95% CI 0.73 to 0.96). NHW candidates with obstructive lung disease and pulmonary fibrosis were older with less illness severity at listing than non-white candidates. CONCLUSIONS: Within the current lung allocation system, there is no difference in risk-adjusted waitlist mortality by race/ethnicity, but non-white waitlist candidates have lower risk-adjusted access to lung transplant. Non-white candidates are generally younger with greater disease-specific illness severity at the time of lung transplant listing.

Hospital cost and length of stay in idiopathic pulmonary fibrosis.

OBJECTIVE: To provide a detailed picture of the economic impact of hospitalization in idiopathic pulmonary fibrosis (IPF) and to identify factors associated with cost and length of stay (LOS). METHODS: In this retrospective cross-sectional study using the Nationwide Inpatient Sample (NIS), this study included hospitalizations for IPF (ICD-9-CM 516.3) with a principal diagnosis of respiratory disease (ICD-9-CM 460-519) from 2009-2011; lung transplant admissions were excluded. Total inpatient cost, LOS, in-hospital death, and discharge disposition were reported. Linear regression models were used to determine variables predictive of LOS and cost. RESULTS: From 2009-2011, 22,350 non-transplant IPF patients with a principal diagnosis of respiratory disease were admitted: mean (±SE) age was 70.0 (0.32), and 49.1% were female. While in hospital, 11.4% of patients received mechanical ventilation and 8.9% received non-invasive ventilation. Mean (±SE) LOS was 7.4 (0.15) days overall (p < .001). The mean (±SD) admission cost was $16,042 (±631). Of hospitalized patients, 14.1% died, 20.6% transferred facilities, and 46.4% were routinely discharged. The adjusted LOS (95% CI) for patients with and without mechanical ventilation was 16.1 days (15-17.5) vs. 6.3 (6-6.5); adjusted costs were $48,772 (43,979-53,565) vs. $11,861 (11,292-12,431). LIMITATIONS: The positive predictive value of the algorithm used to identify IPF is not optimal. The NIS database does not follow patients longitudinally, and claims after admission are not available. Claims do not indicate whether listed diagnoses were present on admission or developed during hospitalization. The exclusion of transplant-related expenditures lead to under-estimation of cost. CONCLUSION: Using a nationally-representative database, we found IPF respiratory-related hospitalizations represent a significant economic burden with ∼7,000 non-transplant IPF admissions per year, at a mean cost of $16,000 per admission. Mechanical ventilation is associated with statistically significant increases in LOS and cost. Therapeutic advances that reduce rates and costs of IPF hospitalizations are needed.

Effect of Transplant Center Volume on Cost and Readmissions in Medicare Lung Transplant Recipients.

RATIONALE: Although lung transplant recipient survival is better at higher volume centers, the effect of center volume on admission cost and early hospital readmission is unknown. OBJECTIVES: To understand the association between transplant center volume and recipient risk-adjusted transplant admission cost, in-hospital mortality, and early hospital readmission in lung transplant recipients. METHODS: Medicare lung transplant recipients from May 4, 2005 to December 31, 2011 were identified through linkage of transplant registry and Medicare administrative claims. Transplant admission cost was extracted, adjusted for regional price variation, and compared across low-, intermediate-, and high-volume centers. A multivariable hierarchical generalized linear regression model was used to assess the effect of transplant center volume on recipient adjusted cost. Modified Poisson regression models were used to assess adjusted in-hospital mortality and early hospital readmission by transplant center volume. MEASUREMENTS AND MAIN RESULTS: There were 3,128 Medicare lung transplant recipients identified. Unadjusted transplant cost was lower at high-volume centers (mean, $131,352 [SD, ±$106,165]; median, $90,177; interquartile range [IQR], $79,165-$137,915) than at intermediate-volume (mean, $138,792 [SD, ±$106,270]; median, $93,024; IQR, $82,700-$154,857) or low-volume (mean, $143,609 [SD, ±$123,316]; median, $95,234; IQR, $83,052-$152,149) centers (P < 0.0001). After adjusting for recipient health risk, low-volume centers had an 11.66% greater transplant admission cost (P = 0.040), a 41% greater risk for in-hospital mortality (P = 0.015), and a 14% greater risk for early hospital readmission (P = 0.033) compared with high-volume centers. There was no significant difference in transplant cost, in-hospital mortality, or early hospital readmission between intermediate- and high-volume centers. CONCLUSIONS: Lung transplant admission cost, in-hospital mortality, and early hospital readmission rate are lower at high-volume centers compared with low-volume centers.

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.