Table 1.

Risk Factors Associated With Increased Morbidity and Mortality in Patients With Polycythemia Vera

Risk Factors
For thrombosis
Age > 60 years
Previous history of thrombosis
Leukocytosis39–42*
Increased JAK2 V617F allele burden6,43–45*
High-risk gene expression profile46*
For transformation to myelofibrosis or secondary acute myeloid leukemia
Older age47
Longer disease duration48
Leukocytosis41
Exposure to phosphorus-32, pipobroman, or chlorambucil7,48
Risk factor associated with decreased survival
Older age7
Leukocytosis7
History of venous thrombosis7
Abnormal karyotype7

^*Emerging or controversial risk factor.