Identifying patients with polycythemia vera at risk of thrombosis after hydroxyurea initiation: The Polycythemia Vera—Advanced Integrated Models (PV-AIM) project

Using electronic health record data from over 80,000 patients with polycythemia vera who were treated with hydroxyurea (HU) only or switched from HU to ruxolitinib, researchers found that the annualized incidence rates (per 100 patients) for HU-only patients decreased from 8.7 before HU to 5.6 during HU but increased to 10.5 when continuing HU. In comparison, incidence rates decreased from 10.8 before HU to 8.4 during HU and was maintained at 8.3 after switching to ruxolitinib. They also used a machine-learning model to identify lymphocyte percentage, neutrophil percentage, and red cell distribution width as key markers of thromboembolic event risk among this patient population.