BackgroundThe prevalence of pulmonary hypertension (PH) in myeloproliferative neoplasms (MPNs) varies among studies. We analyzed the prevalence of PH in Korean patients with Philadelphia-negative (Ph-) MPNs.MethodsMedical records of patients with Ph- MPNs [essential thrombocythemia (ET), poly-cythemia vera (PV), or primary myelofibrosis (PMF)] visiting a single hospital between 1993 and 2019 were reviewed retrospectively. Transthoracic echocardiographic exami-nation (TTE) results were reviewed and PH was diagnosed according to established guidelines.ResultsOf the 320 MPN (179 ET, 107 PV, and 34 PMF) patients, 225 (121 ET, 83 PV, and 21 PMF) underwent TTE. Of these 225 MPN patients, 19 of 121 (15.7%) ET, 9 of 83 (10.8%) PV, and 6 of 21 (28.6%) PMF patients had PH. PV patients with PH were older [71 (42‒85) vs. 61.5 (26‒91) yr, respectively; P=0.049], predominantly female (male:female ratio, 0.29 vs. 1.96, respectively; P=0.010), had lower hemoglobin levels (15.9±2.6 g/dL vs. 18.4±2.6 g/dL, respectively; P=0.010), and higher platelet counts (616.6±284.2×109/L vs. 437.7±191.7×109/L, respectively; P=0.020) than PV patients without PH. PMF pa-tients with PH had higher monocyte counts (1.3±0.5×109/L vs. 0.8±0.4×109/L, re-spectively; P=0.031) than those without PH. PH was a risk factor for poor survival in PV (HR, 12.4; 95% CI, 1.8‒86.6).ConclusionPH is common in patients with Ph- MPNs and hence, careful screening for PH is warranted.