Cytoreductive treatment patterns among US veterans with polycythemia vera.

backgroundPolycythemia vera (PV) is a myeloproliferative neoplasm associated with increased thrombotic and cardiovascular risk, which are key contributors to patient morbidity and mortality. The Veterans Health Administration (VHA) is the largest integrative health network in the United States. Available data concerning patients with PV in this population are limited.

methodsThis retrospective observational study evaluated the characteristics, management, and outcomes of patients with PV in the VHA Medical SAS® Dataset (October 1, 2005, to September 30, 2012). Inclusion criteria were ≥ 2 claims for PV (ie, PV diagnostic code was recorded) ≥30 days apart during the identification period, age ≥ 18 years, and continuous health plan enrollment from ≥12 months before the index date until the end of follow-up. All data were analyzed using descriptive statistics.

resultsThe analysis included 7718 patients (median age, 64 years; male, 98%; white, 64%). The most common comorbidities before the index date were hypertension (72%), dyslipidemia (54%), and diabetes (24%); 33% had a history of smoking. During the follow-up period (median, 4.8 years), most patients did not receive treatment with cytoreductive therapy, including phlebotomy (53%), or antiplatelet agents, such as aspirin (57%). The thrombotic and cardiovascular event rates per 1000 patient-years were 60.5 and 83.8, respectively. Among patients who received cytoreductive treatment, the thrombotic event rate was 48.9 per 1000 patient-years. The overall mortality rate was 51.2 per 1000 patient-years.

conclusionThe notable rates of thrombotic and cardiovascular events observed in this analysis, even among patients receiving cytoreductive treatment, highlight the important unmet clinical needs of patients with PV in the VHA.