Survival of patients with pulmonary hypertension associated with fibrotic interstitial lung disease is not dependent on ILD subtype

The onset of pulmonary hypertension (PH) is a feared complication in patients with interstitial lung disease (ILD). We compared survival in patients with right heart catheterisation-confirmed PH-ILD between subgroups of fibrotic ILD within our UK PH Centre. Data were collected on fibrotic ILD-PH patients diagnosed between 2007-2023, excluding connective tissue disease-ILD, sarcoidosis or if emphysema extent exceeded ILD. Data are mean ± standard deviation or median with interquartile range (IQR). A total of 142 patients, age 65.2 ± 11.2 years, had idiopathic pulmonary fibrosis (IPF) (n=91, 64.1%), idiopathic non-specific interstitial pneumonia (NSIP) (n=15, 10.6%), chronic hypersensitivity pneumonitis (HP) (n=26, 18.3%), post-COVID fibrosis (n=6, 4.2%) and unclassifiable ILD (n=4, 2.8%), with RHC mPAP 34 (29-43) mmHg, PCWP 9 (6-13) mmHg, and PVR 6 (4.6-8.5) Wood units. At the time of PH-ILD diagnosis, FVC was 58.0 (45.7-73.1) % predicted; TLCO 23.5 (17.9-29.9) % and KCO 50.0 (41.0-62.5) % predicted, with 6MW distance (in n=96) 240 (IQR 136-306) m. Survival analysis by ILD subtype is shown in Figure 1, with, 1, 3, and 5-year survival for IPF 53, 17, 4%; HP 57, 20, 20% and NSIP 73, 33, 8%; with no difference between the groups (p=0.3). This is the first study to compare survival between ILD subtypes within one centre. We confirm previous observations in separate cohort studies that once PH is diagnosed, ILD-PH outcomes are similar despite the subtype of underlying ILD.