The prevalence and associated factors of aspirin resistance in JAK2 V617F-mutated essential thrombocythemia and polycythemia vera.

The primary aim was to determine the prevalence of aspirin resistance in JAK2 V617F-mutated essential thrombocythemia and polycythemia vera patients. Secondary objectives included analyzing risk factors for aspirin resistance including JAK2 V617F allele burden. This cross-sectional study included patients aged at least 18 years with JAK2 V617F-mutated essential thrombocythemia and polycythemia vera who were prescribed aspirin. Blood samples were taken to measure JAK2 V617F allele burden and serum thromboxane B2 (TXB2). Aspirin resistance was defined by serum TXB2 levels greater than 570 pg/ml. Clinical characteristics, laboratory data, JAK2 V617F allele burden, and treatment were analyzed to identify risk factors. Seventy-eight patients were enrolled, with 27 (34.6%) having essential thrombocythemia and 51 (65.4%) having polycythemia vera. The prevalence of aspirin resistance was 100%. Factors associated with high TXB2 levels included a history of stroke [95% confidence interval (CI): 1.11-12.34; P  = 0.034], hydroxyurea dose at least 15 mg/kg/day (95% CI: 1.04-8.93; P  = 0.043), and platelet count at least 400 000 cells/μl (95% CI: 1.75-18.86; P  = 0.004). JAK2 V617F allele burden was not significantly correlated with high serum TXB2 ( r2  = 0.087, P  = 0.45). The prevalence of aspirin resistance was 100% in JAK2 V617F-mutated polycythemia vera and essential thrombocythemia patients, based on serum TXB2 levels greater than 570 pg/ml. A history of stroke, hydroxyurea dose at least 15 mg/kg/day, and platelet count at least 400 000 cells/μl were associated with high TXB2 levels.