Prognostic factors in interstitial lung disease-associated pulmonary hypertension: data from the HYPID cohort and the French Pulmonary Hypertension Registry

Background Pulmonary hypertension (PH) frequently complicates interstitial lung diseases (ILD), adversely affecting outcome. Identifying prognostic factors of patients with ILD-PH could facilitate early identification of patients who may benefit from PH therapy. Methods We included patients with ILD-PH from the prospective HYPID cohort and the French National Pulmonary Hypertension Registry (2007–2022). Univariable and multivariable analyses were performed to identify predictors of 1-year mortality. Results A total of 581 patients (mean age 69.4±9.3 years, 450 males) were analysed. ILD diagnoses were combined pulmonary fibrosis and emphysema syndrome (30.8%), idiopathic pulmonary fibrosis (29.6%), unclassifiable ILD (13.1%), and fibrotic hypersensitivity pneumonitis (10.3%). Mean pulmonary artery pressure was 40.7±9.1 mmHg, and mean pulmonary vascular resistance was 7.6 ±3.5 Wood units. Off-label PH therapy was initiated after initial evaluation in 215 patients (37%). The median transplant-free survival time was 17 months (95% CI 15.2 – not reached). Multivariable analysis identified male sex (p<0.001), functional class III (p=0.003) or IV (p=0.003), 6 MWD≤228 m (p<0.001), PVR>5 Wood units (p=0.008), and absence of PH therapy (p<0.001) as independent predictors of death or lung transplantation at 1 year. Conclusion Non-invasive (6 MWD, WHO FC) and invasive (PVR) variables are associated with prognosis in patients with ILD-PH, including in patients with CPFE. PH medication might improve outcomes in this patient population.