Leucocytosis and thrombosis at diagnosis are associated with poor survival in polycythaemia vera: a population‐based study of 327 patients

Three hundred and twenty‐seven patients from two population‐based cohorts with an established diagnosis of polycythaemia vera were studied for prognostic risk factors for survival and leukaemia in a long‐term survey. The relative survival (RS) was 72% and 46% at 10 and 20 years respectively, from the time of diagnosis. Multivariate analysis identified age >70 years, white blood cell count >13 × 10⁹/l and thrombo‐embolism at diagnosis as independent risk factors. Patients with two or three of these factors had a 10 year RS of 26%, compared with 59% and 84% in patients with one and no risk factors, respectively. Age and leucocyte count are the main predicting factors for survival in polycythaemia vera.