Hospitalization Rates in Interstitial Lung Disease: An Analysis of the Pulmonary Fibrosis Foundation Registry.

RATIONALE: Little is known about hospitalization in other types of interstitial lung disease (ILD) besides idiopathic pulmonary fibrosis (IPF). OBJECTIVES: We sought to determine the frequency of hospitalizations in various types of ILD and elucidate the association of hospitalization with outcomes. METHODS: An analysis of the Pulmonary Fibrosis Foundation Patient Registry data was performed. Inpatient hospitalization rates and survival following hospitalization were compared for various types of ILD. RESULTS: Hospitalization rates were similar across ILD types (40.6% of IPF participants, 42.8% of connective tissue disease related ILD (CTD-ILD), 44.9% of non-IPF idiopathic interstitial pneumonia (IIPs), 46.5% of chronic hypersensitivity pneumonitis (CHP) participants, and 53.3% of "other" ILD participants). All-cause hospitalization was not associated with decreased transplant-free survival (adjusted hazard ratio (AHR) 1.20, 95% CI: 0.98, 1.46, p=0.0759) after adjusting for co-morbidities and severity of illness; however respiratory-related hospitalization was (AHR 1.53, 95% CI: 1.23, 1.90, p=0.0001). CTD-ILD (HR 0.43, 95% CI: 0.25, 0.75, p=0.0031) and non-IPF IIP (HR 0.3, 95% CI: 0.15, 0.58, p=0.005) had a lower risk of death following hospitalization compared to IPF while CHP (HR 0.67, 95% CI: 0.37, 1.20, p=0.1747) and "other-ILD" (HR 0.54, 95% CI: 0.19, 1.54, p=0.25) had a comparable risk to IPF. CONCLUSION: Rates of hospitalization are similar across ILD subtypes. The risk of death or transplant following hospitalization is lower in CTD-ILD, CHP and non-IPF IIP compared to IPF participants. In a mixed population of ILD participants, all-cause hospitalizations were not associated with decreased transplant-free survival; however respiratory-related hospitalizations were.

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.

External validation and longitudinal application of the DO-GAP index to individualise survival prediction in idiopathic pulmonary fibrosis.

Background: The Distance-Oxygen-Gender-Age-Physiology (DO-GAP) index has been shown to improve prognostication in idiopathic pulmonary fibrosis (IPF) compared to the Gender-Age-Physiology (GAP) score. We sought to externally validate the DO-GAP index compared to the GAP index for baseline risk assessment in patients with IPF. Additionally, we evaluated the utility of serial change in the DO-GAP index in predicting survival. Methods: We performed an analysis of patients with IPF from the Pulmonary Fibrosis Foundation-Patient Registry (PFF-PR). Discrimination and calibration of the two models were assessed to predict transplant-free survival and IPF-related mortality. Joint longitudinal time-to-event modelling was utilised to individualise survival prediction based on DO-GAP index trajectory. Results: There were 516 patients with IPF from the PFF-PR with available demographics, pulmonary function tests, 6-min walk test data and outcomes included in this analysis. The DO-GAP index (C-statistic: 0.73) demonstrated improved discrimination in discerning transplant-free survival compared to the GAP index (C-statistic: 0.67). DO-GAP index calibration was adequate, and the model retained predictive accuracy to identify IPF-related mortality (C-statistic: 0.74). The DO-GAP index was similarly accurate in the subset of patients taking antifibrotic medications. Serial change in the DO-GAP index improved model discrimination (cross-validated area under the curve: 0.83) enabling the personalised prediction of disease trajectory in individual patients. Conclusion: The DO-GAP index is a simple, validated, multidimensional score that accurately predicts transplant-free survival in patients with IPF and can be adapted longitudinally in individual patients. The DO-GAP may also find use in studies of IPF to risk stratify patients and possibly as a clinical trial end-point.

Prevalence of pulmonary hypertension in patients with COVID-19 related lung disease listed for lung transplantation: A UNOS registry analysis.

COVID-19 related lung disease (CRLD) has emerged as an indication for lung transplantation (LT) in highly select patients. The prevalence and prognostic implication of coexisting pulmonary hypertension (PH) in patients with CRLD listed for LT is not known. Adult patients in the United Network for Organ Sharing database listed for LT for COVID-19 related acute respiratory distress syndrome or fibrosis through March 2022 were identified. The prevalence and impact of precapillary PH on pre- and posttransplantation survival was determined. Time-to-event analysis was used to compare outcomes between those with and without precapillary PH. We identified 245 patients listed for LT for CRLD who had right heart catheterization data available at the time of registry listing. Median age of the cohort was 54 years (interquartile range [IQR]: 46, 60), 56 (22.9%) were female, and the median lung allocation score was 81.3 (IQR: 53.3, 89.4). The prevalence of precapillary PH at the time of transplant listing was 27.9%. There was no significant difference in pretransplant mortality in patients with and without precapillary PH (sHR: 0.5; 95% confidence interval [CI]: 0.1-1.7, p = 0.261). A total of 187 patients ultimately underwent LT; of those, 60 (31.0%) were identified as having precapillary PH during the waitlist period. Posttransplantation survival was similar between patients with and without pretransplant precapillary PH (hazard ratio: 0.96; 95% CI: 0.2-3.7, p = 0.953). We observed a high rate of concomitant precapillary PH in patients listed for LT for CRLD. Though common, coexisting precapillary PH was not associated with a significant difference in either pre- or post-transplantation outcomes.