Abstract / Summary
Background Pulmonary hypertension (PH) is frequent and impactful in respiratory disease, but its characteristics in the Spanish population are unknown. We aimed to describe the clinical features and outcomes of patients with PH associated with COPD, interstitial lung disease (ILD) and combined pulmonary fibrosis and emphysema (CPFE). Methods We analysed patients enrolled in the Spanish Registry of PH Associated with Respiratory Disease (REHAR) from January 2002 to December 2024. Baseline characteristics, haemodynamics, and outcomes were compared across groups and according to severity using the 6th World Symposium on PH (6WSPH) and the 2022 European Society of Cardiology/European Respiratory Society (ESC/ERS) 2022 guidelines. Results Among 434patients, 216 had COPD, 173 had ILD and 45 had CPFE. Severe PH was associated with worse hypoxaemia in all groups. Survival was poorer in ILD and CPFE compared with COPD (p=0.017). In COPD and CPFE, survival was worse in severe PH versus nonsevere PH, using both the 6WSPH (p=0.048 and p=0.021) and the ESC/ERS criteria (p=0.005 and p=0.027). In ILD, neither classification predicted survival (p=0.086 and p=0.270) and no pulmonary vascular resistance threshold discriminated outcomes. Comparing classifications, 31% of patients changed severity category, with reclassified patients showing distinct clinical profiles. Conclusions This study highlights important clinical differences among Spanish patients with COPD, ILD and CPFE. Haemodynamic compromise had a variable impact on survival across diseases, underscoring the heterogeneity of group 3 PH and the need for disease-specific approaches.