Risk factors of thrombosis in patients with PV
| Risk factor . | Effect size . | Reference . |
|---|---|---|
| Age | Age ≥60 y frequently used, but the optimal threshold was unknown; studies using age as continuous variable show increasing risk with older age | 9-14 |
| Presence of cardiovascular risk factors (eg, smoking, hypertension, hyperlipidemia, and diabetes mellitus) | Stronger influence on arterial thrombosis (hazard Ratio [HR] 2.0-4.2) | 9,13-16 |
| Prior thrombosis | Differences between arterial and venous thrombosis; HR, 2.1-9.7 | 9,10,12-17 |
| High-risk mutations | Definition and effects size varies across studies; ASXL1, DNMT3A, TET2, and BCOR/BCORL1 were associated with thrombosis risk in some studies | 9,18 |
| JAK2V617F allele burden | JAK2V617F VAF >50% is associated with higher risk of venous thrombosis; no association with arterial thrombosis | 14-16,19 |
| Leukocytosis | Inconsistent results across studies. WBC count >11 × 109/L or >15 × 109/L was frequently used as threshold for increased risk of thrombosis. Meta-analysis showing stronger association with arterial thrombosis. | 20-23 |
| Treatment | Low-dose aspirin reduces the risk of thrombotic events; hydroxyurea use was associated with a lower risk of thrombosis in nonrandomized study. Limited data available on ruxolitinib and IFN. | 10,24-26 |
| Uncontrolled hematocrit | Hematocrit level <45% is associated with a reduced risk of thrombosis | 10,14,27 |
| Time from diagnosis | Higher risk during first 3 months since diagnosis | 28 |
| Sex | Women had higher rates of venous thromboses; men had more arterial events in the ECLAP study | 29 |
| Thrombocytosis | No clear correlation with thrombosis risk | 21 |
| Risk factor . | Effect size . | Reference . |
|---|---|---|
| Age | Age ≥60 y frequently used, but the optimal threshold was unknown; studies using age as continuous variable show increasing risk with older age | 9-14 |
| Presence of cardiovascular risk factors (eg, smoking, hypertension, hyperlipidemia, and diabetes mellitus) | Stronger influence on arterial thrombosis (hazard Ratio [HR] 2.0-4.2) | 9,13-16 |
| Prior thrombosis | Differences between arterial and venous thrombosis; HR, 2.1-9.7 | 9,10,12-17 |
| High-risk mutations | Definition and effects size varies across studies; ASXL1, DNMT3A, TET2, and BCOR/BCORL1 were associated with thrombosis risk in some studies | 9,18 |
| JAK2V617F allele burden | JAK2V617F VAF >50% is associated with higher risk of venous thrombosis; no association with arterial thrombosis | 14-16,19 |
| Leukocytosis | Inconsistent results across studies. WBC count >11 × 109/L or >15 × 109/L was frequently used as threshold for increased risk of thrombosis. Meta-analysis showing stronger association with arterial thrombosis. | 20-23 |
| Treatment | Low-dose aspirin reduces the risk of thrombotic events; hydroxyurea use was associated with a lower risk of thrombosis in nonrandomized study. Limited data available on ruxolitinib and IFN. | 10,24-26 |
| Uncontrolled hematocrit | Hematocrit level <45% is associated with a reduced risk of thrombosis | 10,14,27 |
| Time from diagnosis | Higher risk during first 3 months since diagnosis | 28 |
| Sex | Women had higher rates of venous thromboses; men had more arterial events in the ECLAP study | 29 |
| Thrombocytosis | No clear correlation with thrombosis risk | 21 |
WBC, white blood cell.