GDF2 and idiopathic pulmonary arterial hypertension: We further validated that plasma BMP9 levels discriminated PoPH from IPAH subjects, maintaining discrimination for PoPH in the full cohort (PoPH, non-PoPH cirrhosis, and IPAH), even after adjustment for age, sex, race/ethnicity, and BMI (AUC of 0.789, 95% CI 0.716–0.861) (Fig. 3e, Table 3).