Risk factors and incidence of thrombosis in a Brazilian cohort of patients with Philadelphia-negative myeloproliferative neoplasms.

Few data are available regarding epidemiology and outcomes of Philadelphia-negative chronic myeloproliferative neoplasms (MPN) in Latin America. Therefore, current models for MPN treatment are based in large cohorts of patients from Europe and North America. In this paper, we conducted a retrospective study to evaluate thrombotic and bleeding events in a cohort of patients with MPN from a reference center in Brazil. A total of 334 patients were included, being essential thrombocythemia the most common diagnosis. Here, we found that 41% of the MPN patients had a thrombotic event prior to the diagnosis. Thrombosis was more frequent in patients under 60 years-old. In a multivariable model, only JAK2 V617F mutation (OR 2.57 95% CI 1.58-4.18, p < 0.001) and presence of two cardiovascular risk factors (OR 1.90 95% CI 1.21-2.98, p < 0.005) were significant for thrombosis. The risk of thrombosis was similar among all subtypes of MPN. Cumulative incidence of thromboembolic event at 5 years from diagnosis was 5.8% (95% CI 3.5-8.9), which is similar to previous studies. The high incidence of thromboembolic events in younger patients suggests that socioeconomic disparities might have a role in the outcomes of MPN.