Pulmonary hypertension in patients with chronic obstructive lung disease: results from COMPERA

BACKGROUND: Pulmonary hypertension in chronic obstructive pulmonary disease (PH-COPD) is a poorly investigated clinical condition. RESEARCH QUESTION: Which factors determine outcome of PH-COPD? STUDY DESIGN AND METHODS: We analyzed the characteristics and outcome of patients enrolled in the COMPERA registry with moderate or severe PH-COPD as defined during the 6$^{th}$ PH World Symposium who received medical therapy for PH and compared them to patients with idiopathic pulmonary arterial hypertension (IPAH). RESULTS: The population included incident patients with moderate PH-COPD (n=68), severe PH-COPD (n=307), and IPAH (n=489). PH-COPD subjects were older, predominantly male, and treated mainly with phosphodiesterase-5 inhibitors. Despite similar hemodynamic impairment, patients with PH-COPD had a worse 6-minute walking distance (6MWD) and more advanced World Health Organization functional class (WHO FC). Transplant-free survival rates at 1, 3 and 5 years were higher in the IPAH group than in the PH-COPD group (IPAH 94%, 75%, 55%, vs PH-COPD 86%, 55%, 38%; p=0.004). Risk factors for poor outcomes in PH-COPD were male sex, low 6MWD and high pulmonary vascular resistance (PVR). In patients with severe PH-COPD, improvements in 6MWD by ≥30m or improvements in WHO FC after initiation of medical therapy were associated with better outcome. INTERPRETATION: Patients with PH-COPD were functionally more impaired and had a poorer outcome than patients with IPAH. Predictors of death in the PH-COPD group were sex, 6MWD and PVR. Our data raise the hypothesis that some patients with severe PH-COPD may benefit from PH treatment. Randomized, controlled studies are necessary to further explore this hypothesis