Presenting clinical and laboratory characteristics of 710 patients with ET stratified according to presence or absence of ExT (≥1500 × 109/L) at diagnosis
| Variable . | All patients (N = 710) . | Patients with platelet count ≥1500 × 109/L at diagnosis (n = 41) . | Patients with platelet count <1500 × 109/L at diagnosis (n = 669) . | P, univariate . | P, age-adjusted . | P, multivariate . |
|---|---|---|---|---|---|---|
| Age, median (range), y | 58 (18-90) | 40 (19-86) | 59 (18-90) | <.0001 | <.0001 | |
| Age >60 y, N (%) | 330 (46) | 8 (20) | 322 (48) | .0004 | <.0001 | |
| Female, N (%) | 450 (63) | 30 (73) | 420 (63) | .18 | ||
| Hemoglobin, median (range), g/dL | 13.9 (11-16.3) | 13.1 (11.1-15.6) | 13.9 (11-16.3) | .001 | .001 | .005 |
| Leukocyte count, median (range), 109/L | 8.6 (3.5-28.1) | 10.4 (4.3-28.1) | 8.5 (3.5-27.1) | .0003 | .0002 | <.0001 |
| Leukocyte count ≥11 × 109/L, N (%) | 153/703 (22) | 17/40 (43) | 136/663 (21) | .001 | .001 | <.0001 |
| Cardiovascular risk factors, n/N (%) | 340/646 (53) | 13/37 (35) | 327/609 (54) | .03 | .49 | |
| Diabetes mellitus | 61/648 (9) | 2/38 (5) | 59/610 (10) | .37 | ||
| Hypertension | 275/649 (42) | 7/38 (18) | 268/611 (44) | .002 | .1 | |
| Smoking | 151/642 (24) | 10/36 (28) | 141/606 (23) | .53 | ||
| Palpable splenomegaly, n/N (%) | 85/705 (12) | 8/40 (20) | 77/665 (12) | .11 | ||
| Driver mutation status, N (%) | ||||||
| JAK2V617F | 427 (60) | 14 (34) | 413 (62) | |||
| CALR | 191 (27) | 18 (44) | 173 (26) | .001 | .03 | 0.1 |
| Type 1 CALR | 61 | 5 | 56 | |||
| Type 2 CALR | 47 | 10 | 37 | |||
| MPL | 20 (3) | 0 (0) | 20 (3) | |||
| Triple negative | 72 (10) | 9 (22) | 63 (9) | |||
| Next-generation sequencing, N (%) | n = 244 | n = 14 | n = 230 | |||
| SF3B1 | 6 (3) | 0 (0) | 6 (3) | .54 | ||
| SRSF2 | 7 (3) | 0 (0) | 7 (3) | .51 | ||
| U2AF1 | 2 (0.8) | 1 (7) | 1 (0.4) | .01 | .04 | .12 |
| ASXL1 | 12 (5) | 1 (7) | 11 (5) | .69 | ||
| EZH2 | 3 (1) | 1 (7) | 2 (0.9) | .04 | .08 | |
| IDH1/2 | 2 (0.8) | 0 (0) | 2 (0.9) | .73 | ||
| TP53 | 4 (2) | 1 (7) | 3 (1) | .09 | ||
| Major thrombosis at or before diagnosis, N (%) | ||||||
| Arterial thrombosis* | 94/709 (13) | 3/41 (7) | 91/668 (14) | .25 | ||
| Venous thrombosis† | 69/709 (10) | 5/41 (12) | 64/668 (10) | .58 | ||
| Major hemorrhage at or before diagnosis,‡ N (%) | 32/692 (5) | 6/40 (15) | 26/652 (4) | .001 | .01 | .02 |
| Microvascular symptoms,§ N (%) | 156/663 (24) | 9/40 (23) | 147/623 (24) | .87 | ||
| Revised IPSET-thrombosis, N (%) | n = 709 | n = 41 | n = 668 | |||
| Very low | 161 (23) | 19 (46) | 142 (21) | .001 | .08 | |
| Low | 155 (22) | 8 (20) | 147 (22) | |||
| Intermediate | 83 (12) | 5 (12) | 78 (12) | |||
| High | 310 (44) | 9 (22) | 301 (45) | |||
| Treatment instituted at diagnosis, N (%) | ||||||
| Aspirin | 317/400 (79) | 22/36 (61) | 300/372 (81) | .01 | ||
| Cytoreductive therapy‖ | 203/414 (49) | 26/38 (68) | 183/383 (48) | .02 | ||
| Variable . | All patients (N = 710) . | Patients with platelet count ≥1500 × 109/L at diagnosis (n = 41) . | Patients with platelet count <1500 × 109/L at diagnosis (n = 669) . | P, univariate . | P, age-adjusted . | P, multivariate . |
|---|---|---|---|---|---|---|
| Age, median (range), y | 58 (18-90) | 40 (19-86) | 59 (18-90) | <.0001 | <.0001 | |
| Age >60 y, N (%) | 330 (46) | 8 (20) | 322 (48) | .0004 | <.0001 | |
| Female, N (%) | 450 (63) | 30 (73) | 420 (63) | .18 | ||
| Hemoglobin, median (range), g/dL | 13.9 (11-16.3) | 13.1 (11.1-15.6) | 13.9 (11-16.3) | .001 | .001 | .005 |
| Leukocyte count, median (range), 109/L | 8.6 (3.5-28.1) | 10.4 (4.3-28.1) | 8.5 (3.5-27.1) | .0003 | .0002 | <.0001 |
| Leukocyte count ≥11 × 109/L, N (%) | 153/703 (22) | 17/40 (43) | 136/663 (21) | .001 | .001 | <.0001 |
| Cardiovascular risk factors, n/N (%) | 340/646 (53) | 13/37 (35) | 327/609 (54) | .03 | .49 | |
| Diabetes mellitus | 61/648 (9) | 2/38 (5) | 59/610 (10) | .37 | ||
| Hypertension | 275/649 (42) | 7/38 (18) | 268/611 (44) | .002 | .1 | |
| Smoking | 151/642 (24) | 10/36 (28) | 141/606 (23) | .53 | ||
| Palpable splenomegaly, n/N (%) | 85/705 (12) | 8/40 (20) | 77/665 (12) | .11 | ||
| Driver mutation status, N (%) | ||||||
| JAK2V617F | 427 (60) | 14 (34) | 413 (62) | |||
| CALR | 191 (27) | 18 (44) | 173 (26) | .001 | .03 | 0.1 |
| Type 1 CALR | 61 | 5 | 56 | |||
| Type 2 CALR | 47 | 10 | 37 | |||
| MPL | 20 (3) | 0 (0) | 20 (3) | |||
| Triple negative | 72 (10) | 9 (22) | 63 (9) | |||
| Next-generation sequencing, N (%) | n = 244 | n = 14 | n = 230 | |||
| SF3B1 | 6 (3) | 0 (0) | 6 (3) | .54 | ||
| SRSF2 | 7 (3) | 0 (0) | 7 (3) | .51 | ||
| U2AF1 | 2 (0.8) | 1 (7) | 1 (0.4) | .01 | .04 | .12 |
| ASXL1 | 12 (5) | 1 (7) | 11 (5) | .69 | ||
| EZH2 | 3 (1) | 1 (7) | 2 (0.9) | .04 | .08 | |
| IDH1/2 | 2 (0.8) | 0 (0) | 2 (0.9) | .73 | ||
| TP53 | 4 (2) | 1 (7) | 3 (1) | .09 | ||
| Major thrombosis at or before diagnosis, N (%) | ||||||
| Arterial thrombosis* | 94/709 (13) | 3/41 (7) | 91/668 (14) | .25 | ||
| Venous thrombosis† | 69/709 (10) | 5/41 (12) | 64/668 (10) | .58 | ||
| Major hemorrhage at or before diagnosis,‡ N (%) | 32/692 (5) | 6/40 (15) | 26/652 (4) | .001 | .01 | .02 |
| Microvascular symptoms,§ N (%) | 156/663 (24) | 9/40 (23) | 147/623 (24) | .87 | ||
| Revised IPSET-thrombosis, N (%) | n = 709 | n = 41 | n = 668 | |||
| Very low | 161 (23) | 19 (46) | 142 (21) | .001 | .08 | |
| Low | 155 (22) | 8 (20) | 147 (22) | |||
| Intermediate | 83 (12) | 5 (12) | 78 (12) | |||
| High | 310 (44) | 9 (22) | 301 (45) | |||
| Treatment instituted at diagnosis, N (%) | ||||||
| Aspirin | 317/400 (79) | 22/36 (61) | 300/372 (81) | .01 | ||
| Cytoreductive therapy‖ | 203/414 (49) | 26/38 (68) | 183/383 (48) | .02 | ||
IPSET-thrombosis, International prognostic score for thrombosis in ET. P values in bold are statistically significant, defined as < 0.05.
Major arterial thrombosis includes myocardial infarction, angina, cerebrovascular accidents, transient ischemic attack, peripheral arterial thrombosis, aortic thrombosis, mesenteric artery thrombosis, and central retinal thrombosis.
Major venous thrombosis includes deep venous thrombosis, pulmonary embolism, portal/splenic/mesenteric/hepatic vein thrombosis, and cerebral sinus thrombosis.
Major hemorrhage includes bleeding events that require red cell transfusion support, resulted in ≥2 g/dL decline in hemoglobin, or involved critical organs.
Microvascular symptoms include headaches, paresthesia, and erythromelalgia.
Cytoreductive therapies include hydroxyurea, anagrelide, and interferon.