GSTM1 and polycythemia: When stratified by median values, the proportion of patients with values above the median in the thrombotic group was significantly higher than the non-thrombotic group (RBC ≥ 4.7×1012/L: 62.4% vs 45.3%; Hb ≥ 136g/L: 65.6% vs 44.0%; HCT ≥ 0.42: 63.4% vs 44.9%, all P < 0.05), while WBC, NLR and PLT were not associated with thrombosis (P > 0.05), suggesting that MPN patients with erythrocytosis are more prone to thrombotic events.