In this study of adults with sickle cell disease, the prevalence of pulmonary hypertension as confirmed on right heart catheterization was 6%. Echocardiographic evaluation alone had a low positive predictive value for pulmonary hypertension. (Funded by the French Ministry of Health and Assistance Publique-Hôpitaux de Paris; ClinicalTrials.gov number, NCT00434902.).

Pulmonary arterial hypertension (PAH) is a progressive, fatal disease.We studied 674 consecutive adult patients who were prospectively enrolled in the French PAH registry (121 incident and 553 prevalent cases). Two survival analyses were performed. First, the cohort of 674 patients was followed for 3 yrs after study entry and survival rates described. Then, we focused on the subset with incident idiopathic, familial and anorexigen-associated PAH (n556) combined with prevalent patients who were diagnosed ,3 yrs prior to study entry (n5134).In the cohort of 674 patients, 1-, 2-, and 3-yr survival rates were 87% (95% CI 84-90), 76% (95% CI 73-80), and 67% (95% CI 63-71), respectively. In prevalent idiopathic, familial and anorexigenassociated PAH, 1-, 2-, and 3-yr survival rates were higher than in incident patients (p50.037). In the combined cohort of patients with idiopathic, familial and anorexigen-associated PAH, multivariable analysis showed that survival could be estimated by means of a novel riskprediction equation using patient sex, 6-min walk distance, and cardiac output at diagnosis.This study highlights survivor bias in prevalent cohorts of PAH patients. Survival of idiopathic, familial and anorexigen-associated PAH can be characterised by means of a novel risk-prediction equation using patients' characteristics at diagnosis.