Pruritus in polycythemia vera is associated with a lower risk of arterial thrombosis.

Among 418 patients with polycythemia vera seen at our institution and in whom pruritus history was recorded, the presence of pruritus at diagnosis was documented in 131 (31%) and its absence in 287 (69%). Pruritus was less frequently reported by smokers (12% vs. 24%; P = 0.004) and diabetics (5% vs. 11%; P = 0.04). The presence of pruritus was associated with a lower rate of arterial thrombosis, both at diagnosis (8% vs. 17%; P = 0.01) and during follow-up (16% vs. 30%; P = 0.003). Multivariable analysis revealed that these associations were independent of other risk factors for thrombosis. High JAK2V617F allele burden clustered with pruritus (P = 0.002) but did not affect thrombosis rates. Copyright 2008 Wiley-Liss, Inc.