[A study of clinical characteristics and prognosis of primary myelofibrosis patients with thrombocytopenia in varied degrees].

Objective

To evaluate clinical characteristics and prognosis of primary myelofibrosis (PMF) patients with thrombocytopenia in varied degrees.

Methods

Clinical features and survival data of 1 305 Chinese patients with PMF were retrospectively analyzed. The prognostic value of thrombocytopenia in patients with PMF was evaluated.

Results

320 subjects (47%) presented severe thrombocytopenia (PLT<50×10(9)/L), 198 ones (15.2%) mild thrombocytopenia [PLT (50-99)×10(9)/L] and 787 ones (60.3%) without thrombocytopenia (PLT ≥ 100×10(9)/L). The more severe the thrombocytopenia, the higher the proportions of HGB<100 g/L, WBC<4×10(9)/L, circulating blasts ≥ 3%, abnormal karyotype and unfavourable cytogenetics (P<0.001, P<0.001, P=0.004, P<0.001 and P<0.001, respectively) were observed in this cohort of patients. The more severe the thrombocytopenia, the lower the proportion of JAK2V617F positive (P<0.001) was also noticed. Platelet count was positively correlated with splenomegaly, HGB and WBC (P<0.001, correlation coefficients were 0.131, 0.445 and 0.156, respectively). Platelet count was negative correlated with constitutional symptoms and circulating blasts (P=0.009, P=0.045, respectively; correlation coefficients were -0.096 and -0.056, respectively). The median survival of patients with severe thrombocytopenia, mild thrombocytopenia and without thrombocytopenia were 32, 67 and 89 months, respectively (P<0.001). Multivariate analysis identified thrombocytopenia in varied degrees (HR=1.693, 95%CI 1.320-2.173, P<0.001) and Dynamic Internation Prognostic Scoring System(DIPSS) prognostic model (HR=2.051, 95%CI 1.511-2.784, P<0.001) as independent risk factors for survival.

Conclusion

PMF patients with severe thrombocytopenia frequently displayed anemia, leucopenia, circulating blasts and short survival, so active treatment measures should be taken especially in these patients.