In young patients with polycythemia vera or essential thrombocythemia, molecular characterization can be used to determine the risk of thrombosis and disease progression, according to recent findings. Researchers studied data on 97 patients who had splanchnic vein thrombosis (SVT) at diagnosis (n=69, median age 43 years) or during follow-up (n=21, median age 46 years). These patients were matched by sex and age to a control group that did not have SVT (n=165, median age 48 years). Most patients with SVT at diagnosis had heterozygous JAK2 mutation (87% of cases vs 69% in control group, P<0.05), but despite the low JAK2 allele burden and absence of high-risk mutations, patients in the SVT group still had a higher risk of death (HR 3.0, 95% CI 1.5-6.0, P=0.003) and lower eventfree survival (HR 3.0, 95% CI 1.9–4.8, P<0.001) than the control group. Researchers also found an association between molecular high-risk status and an increased risk of venous re-thrombosis (HR 5.8, 95% CI 1.4–24.0, P=0.01) in patients with SVT. More patients who developed SVT during follow-up had molecular high-risk status than those with SVT at diagnosis (52% vs 13%, P<0.05).
