The objectives of the study were to estimate the incidence of Wernicke's encephalopathy (WE) and cardiac disorders among patients with myeloproliferative neoplasms (MPN), and compare it with those without MPN. A total of 39,761 MPN patients were identified from the US Marketscan database. Approximately 27% of them were 65+ years of age, and 51% were male. Patients with MPN had higher rates of WE, compared to those without MPN (MPN vs. non-MPN: 1.09 vs. 0.39/1000 person-year, adjusted HR = 2.19, 95%CI 1.43-3.34). Patients with MPN also had higher rates of cardiac events (congestive heart failure: MPN vs. non-MPN: 9.27 vs. 3.70/1000 person-year, adjusted HR= 1.64, 95%CI 1.42-1.88; acute myocardial infarction: MPN vs. non-MPN: 10.45 vs. 5.02/1000 person-year, adjusted HR = 1.44, 95%CI 1.27, 1.63; cardiac arrhythmia: MPN vs. non-MPN: 106.5 vs. 53.9/1000 person-year, adjusted HR= 1.42, 95%CI 1.36-1.48). Physicians who care for patients with MPN should be aware of increased risk of WE and cardiac disorders in this population. [ABSTRACT FROM AUTHOR]