DeciPHer-ILD: A Real-world Patient Registry in Group 3 Pulmonary Hypertension Associated With Interstitial Lung Disease (PH-ILD)

Inclusion Criteria: 1. Adults aged 18 years or older 2. Diagnosis of fibrotic ILD based on high-resolution computed tomography imaging, including but not limited to: 1. Idiopathic interstitial pneumonia, including idiopathic pulmonary fibrosis 2. Autoimmune ILD 3. Chronic hypersensitivity pneumonitis 4. Nonspecific interstitial pneumonia 5. Occupational lung disease 6. Combined pulmonary fibrosis and emphysema with fibrosis greater than the extent of emphysema on lung imaging as determined by the Investigator 3. For patients to be eligible for Cohorts 1 to 3: RHC confirmed PH (mean pulmonary artery pressure \>20 mmHg, pulmonary artery wedge pressure ≤15 mmHg, pulmonary vascular resistance \>2 WU). 4. For patients to be eligible for Cohort 1, they must not be receiving inhaled treprostinil at Baseline. 5. For patients to be eligible for Cohort 2, they must have initiated Tyvaso/Tyvaso DPI at 1 of the following time points: 1. Baseline 2. ≤90 days prior to Baseline 6. For patients to be eligible for Cohort 3, they must be receiving Tyvaso/Tyvaso DPI at Baseline and for \>90 days prior to Baseline. 7. For patients to be eligible for Cohort 4: Prior RHC not meeting the definition of PH as described in Inclusion Criterion 3 but has a pulmonary artery wedge pressure ≤15 mmHg. 8. Co-enrollment in other observational or interventional studies is permitted. 9. Patient is willing and able to provide informed consent and complete surveys/questionnaires in English or Spanish. Exclusion Criteria: 1. Confirmed diagnosis of Group 1, 2, 4, or 5 PH a. In cases in which a patient has a diagnosis of PH-ILD along with a concomitant diagnosis of another PH group (eg, Group 1), enrollment may be permitted at the Investigator's discretion if, in their clinical judgment, PH-ILD is the predominant driver of the patient's PH. 2. Confirmed diagnosis of Group 3 PH associated with lung diseases and or hypoxia other than fibrotic ILD, as outlined in Inclusion Criterion 2. 3. Patients receiving inhaled treprostinil (Yutrepia™) at Baseline. Patients receiving other forms of PH therapy will be eligible for enrollment.