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 × 10(9) /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.