Prognostic factors in idiopathic myelofibrosis: a simple scoring system with prognostic significance.

In a prognostic univariate analysis of a series of 80 patients with idiopathic myelofibrosis the Hb-concentration, the platelet count and osteomyelosclerosis emerged as factors with prognostic significance. A Hb-concentration less than 10 g/dl was associated with a significantly shorter survival than a Hb-concentration greater than or equal to 10 g/dl. A platelet count less than 100 x 10(9)/l also implied a significantly shorter survival. Patients with osteomyelosclerosis on X-ray of the skeleton had a significantly better prognosis as compared to those without osteomyelosclerosis. In a multivariate regression analysis the Hb-concentration consistently emerged as an important prognostic parameter, whereas the platelet count was only of prognostic significance within the first 6 months from diagnosis and the presence of osteomyelosclerosis emerged as a favourable parameter at 3 and 5 years. Based upon the above parameters and spleen size, a prognostic scoring system was designed which categorized the patients into three prognostic groups with highly different survival times (low risk group = 69 months; intermediate risk group = 33 months; high risk group = 4 months).