Prevalence, incidence, and thromboembolic events in polycythemia vera: a study based on longitudinal German health claims data.

There is little evidence, particularly in Germany, on the epidemiology and the cytoreductive management of polycythemia vera (PV). We performed an observational study based on anonymized health claims data to provide estimates of the epidemiology of PV in Germany, to describe the use of cytoreductive drugs in patients with PV, and to assess the occurrence of thromboembolic events (TEs) in prevalent patients on continuous treatment with relevant cytoreductive drugs over time. For the year 2021, we estimated a PV prevalence of 28.6 per 100,000 and an incidence of 3.3 per 100,000 in the German adult population (≥ 18 years). We identified 83.2% of prevalent patients in 2021 as being at high risk for thromboembolic complications, based on age (≥ 60 years) and/or history of TEs. Contrary to treatment guidelines, 43.6% of these high-risk patients did not receive cytoreductive drug treatment in 2021. 63.5% of patients in 2021 who were treated with hydroxyurea (but not ruxolitinib) in that year, met our defined proxy criteria for intolerance/resistance to hydroxyurea. Over time, we observed a lower proportion of patients with TEs in patients continuously treated with ruxolitinib compared to patients treated with hydroxyurea who also met our defined proxy criteria for intolerance/resistance to hydroxyurea (35.8% vs. 56.3% after three years). Our findings suggest that currently available cytoreductive therapies are not being fully utilized according to treatment guidelines, which may lead to avoidable thromboembolic complications in this patient population.