Table 1.
Presenting clinical and laboratory characteristics of 1000 patients with essential thrombocythemia (ET) stratified by driver mutation (JAK2, CALR, MPL, triple negative).
| Variables | All patients n = 1000 | JAK2 mutated n = 659 (66%) | CALR mutated n = 187 (19%) | MPL mutated n = 44 (4%) | Triple negative n = 110 (11%) | P-value JAK2 vs CALR | P-value JAK2 vs MPL | P-value JAK2 vs Triple negative | P-value CALR vs Triple negative |
|---|---|---|---|---|---|---|---|---|---|
| Age in years, median (range) | 59 (18–95) | 62 (18–95) | 53 (19–95) | 59 (25–89) | 53 (18–87) | <0.001 | 0.92 | <0.001 | 0.51 |
| Age ≥ 60 years, n (%) | 484 (48) | 353 (54) | 69 (37) | 21 (48) | 41 (37) | <0.001 | 0.43 | 0.002 | 0.95 |
| Female gender, n (%) | 646 (65) | 440 (67) | 87 (46) | 35 (80) | 84 (76) | <0.001 | 0.08 | 0.04 | <0.001 |
| Hemoglobin g/dL, median (range) | 14 (10–17.6) | 14.2 (10–17.6) | 13.8 (11–17.2) | 13.1 (11.1–17) | 13.7 (11.5–16.7) | <0.001 | <0.001 | <0.001 | 0.91 |
| Leukocyte count, 109/L, median (range) | 8.5 (3.2–22) | 8.7 (3.2–22) | 8.0 (3.8–13.5) | 7.7 (4–16.6) | 8 (4.2–21.5) | <0.001 | 0.004 | 0.07 | 0.09 |
| Leukocyte count > 11 × 109/L, n (%) | 160 (16) | 120 (18) | 15 (8) | 7 (16) | 18 (16) | <0.001 | 0.73 | 0.64 | 0.03 |
| Platelet count, 109/L, median (range) | 715 (450–2088) | 671 (450–1881) | 826 (464–2088) | 838 (451–1742) | 725 (461–1700) | <0.001 | <0.001 | 0.005 | 0.002 |
| Platelet count ≥ 1000 × 109/L, n (%) | 156 (16) | 70 (11) | 52 (28) | 11 (25) | 23 (21) | <0.001 | 0.004 | 0.002 | 0.19 |
| Platelet count ≥ 1500 × 109/L, n (%) | 96 (10) | 22 (4) | 67 (36) | 4 (9) | 3 (3) | <0.001 | 0.07 | 0.73 | 0.001 |
| Cardiovascular risk factors, n (%) | 518 (52) | 364 (55) | 84 (45) | 23 (52) | 47 (43) | 0.01 | 0.71 | 0.02 | 0.71 |
| Diabetes mellitus | 62 (6) | 45 (7) | 7 (4) | 2 (4) | 8 (7) | 0.13 | 0.55 | 0.86 | 0.18 |
| Hypertension | 347 (35) | 244 (37) | 57 (30) | 17 (39) | 29 (26) | 0.09 | 0.83 | 0.03 | 0.45 |
| Smoking | 161 (16) | 112 (17) | 25 (13) | 6 (14) | 18 (16) | 0.22 | 0.56 | 0.87 | 0.48 |
| Hyperlipidemia | 181 (18) | 129 (20) | 28 (15) | 9 (20) | 15 (14) | 0.1 | 0.89 | 0.14 | 0.75 |
| Palpable splenomegaly, n (%) | 126 (13) | 90 (14) | 22 (12) | 3 (7) | 11 (10) | 0.52 | 0.21 | 0.29 | 0.64 |
| Abnormal karyotype, n (%) | 30 (10) | 22/197 (11) | 3/62 (5) | 1/15 (7) | 4/25 (16) | 0.10 | 0.63 | 0.48 | 0.08 |
| N evaluable = 299 | |||||||||
| Major thrombosis at or prior to diagnosis, n (%) | 186 (19) | 149 (23) | 16 (9) | 10 (23) | 11 (10) | <0.001 | 0.94 | 0.003 | 0.68 |
| Arterial thrombosisa | 132 (13) | 106 (16) | 13 (7) | 5 (11) | 8 (7) | 0.001 | 0.42 | 0.02 | 0.92 |
| Venous thrombosisb | 63 (6) | 50 (8) | 4 (2) | 6 (14) | 3 (3) | 0.007 | 0.12 | 0.06 | 0.75 |
| Major hemorrhage at or prior to diagnosis, n (%) | 42 (4) | 22 (3) | 11 (6) | 2 (4) | 7 (6) | 0.12 | 0.89 | 0.14 | 0.90 |
| Microvascular symptoms, n (%) | 293 (29) | 176 (27) | 60 (32) | 23 (52) | 34 (31) | 0.17 | 0.001 | 0.36 | 0.83 |
| IPSETa thrombosis, n (%) | |||||||||
| Low | 244 (24) | 0(0) | 136 (73) | 24 (54) | 84 (76) | <0.001 | <0.001 | <0.001 | 0.5 |
| Intermediate | 221 (22) | 157 (24) | 37 (20) | 11 (25) | 16 (15) | ||||
| High | 535 (54) | 502 (76) | 14 (7) | 9 (21) | 10 (9) | ||||
| Revised IPSET-thrombosis, n (%) | |||||||||
| Very Low | 200 (20) | 0 (0) | 114 (61) | 20 (45) | 66 (60) | – | 0.81 | ||
| Low | 248 (25) | 248 (38) | 0 (0) | 0 (0) | 0 (0) | ||||
| Intermediate | 104 (10) | 0 (0) | 57 (30) | 14 (32) | 33 (30) | ||||
| High | 448 (45) | 411 (62) | 16 (9) | 10 (23) | 11 (10) | ||||
| IPSET-survivalb, n (%) | |||||||||
| Low | 380 (38) | 202 (30) | 105 (56) | 17 (39) | 56 (51) | <0.001 | 0.54 | <0.001 | 0.53 |
| Intermediate | 437 (44) | 314 (48) | 65 (35) | 18 (41) | 40 (36) | ||||
| High | 183 (18) | 143 (22) | 17 (9) | 9 (20) | 14 (13) | ||||
| Treatment instituted at diagnosis, n (%) | |||||||||
| Antiplatelet therapy | 897 (90) | 607 (92) | 155 (83) | 41 (93) | 94 (85) | 0.001 | 0.81 | 0.02 | 0.56 |
| Cytoreductive therapyc | 701 (70) | 483 (73) | 136 (72) | 32 (73) | 50 (45) | 0.82 | 0.93 | <0.001 | <0.001 |
| Systemic anticoagulation | 111 (11) | 75 (11) | 20 (11) | 8 (18) | 8 (7) | 0.84 | 0.18 | 0.20 | 0.33 |
Significant p-values are highlighted in bold.
aInternational prognostic score for thrombosis in ET (IPSET-thrombosis).
bInternational prognostic score for survival in ET (IPSET-survival).
cCytoreductive therapies included hydroxyurea, anagrelide, interferon, busulphan, ruxolitinib.