Mortality outcomes and survival patterns of patients with myeloproliferative neoplasms in Malaysia

Abstract

Background: Prognostication of myeloproliferative neoplasm (MPN) has always been challenging, even with the advent of Janus kinase 2 (JAK2 V617F) molecular studies. The survival pattern of patients diagnosed with MPN in developing countries is still undetermined.

Materials and methods: The national MPN registry conducted from 2009 to 2015 in Malaysia provided a comprehensive insight into the demographics, clinical characteristics and laboratory parameters of patients diagnosed with MPN nationwide. The study analysed the survival patterns and mortality outcomes and risk among 671 patients diagnosed with essential thrombocythaemia (ET), polycythaemia vera (PV), primary myelofibrosis (PMF) and unclassified MPN (MPN-U). Mortality status was traced and confirmed until the end of December 2018, with right censoring applied to patients alive beyond that.

Results: The analysed cohort consisted of 283 (42.2%) ET, 269 (40.1%) PV, 62 (9.2%) PMF and 57 (8.5%) MPN-U incident cases with diagnosis made between 2007 and 2015. The majority of patients were male (52.3%) and Malay (48.9%), except for ET, in which the majority of patients were female (60.1%) and of Chinese origin (47.0%). Female patients were found to have significantly better overall survival (OS) rates in ET (p = 0.0285) and MPN-U (p = 0.0070). Patients with JAK2 V617F mutation were found to have marginally inferior OS over time. Multivariable Cox regression identified patients with increased age [hazard ratio (HR) 1.055, 95% CI 1.031; 1.064], reduced haemoglobin (HB) level (HR 0.886, 95% CI 0.831; 0.945, p = 0.0002), being male (HR 1.545, 95% CI 1.077; 2.217, p = 0.0182), and having MPN-U (HR 2.383, 95% CI 1.261; 4.503, p = 0.0075) and PMF (HR 1.975, 95% CI 1.054; 3.701, p = 0.0335) at increased risk for worse mortality outcomes.

Conclusion: Myeloproliferative neoplasm reduces patient survival. The degree of impact on survival varies according to sub-type, sex, bone marrow fibrosis and HB levels. The JAK2 V617F mutation was not found to affect the survival pattern or mortality outcome significantly.

Keywords: Essential thrombocythaemia; Janus kinase; Myeloproliferative neoplasm; Overall survival; Polycythaemia vera; Primary myelofibrosis; Unclassified MPN.