Table 1

Clinical and laboratory features of 884 karyotypically annotated patients with primary myelofibrosis at the time of referral to the Mayo Clinic, stratified according to presence or absence of predictors for early death

VariablesAll patients (n = 884)Very high-risk group* (n = 52)Patients with MK (n = 19)Patients with inv(3)/i(17q) abnormalities (n = 8)Patients with PB blasts > 9% and without MK or inv(3)/i(17q) (n = 30)Patients with WBC ≥ 40 × 109/L and without PB blasts > 9%, MK, or inv(3)/i(17q) (n = 68)Patients with none of the above (n = 759)P
Median age, y (range)65 (14-92)65 (30-83)63 (30-83)72 (59-80)63 (44-76)69 (27-85)65 (14-92).06
Age > 65 y, n (%)429 (49)25 (48)8 (42)5 (63)12 (40)40 (59)364 (48).31
Males, n (%)562 (63)33 (64)9 (47)7 (88)21 (70)39 (57)486 (64).21
Hemoglobin, g/dL, median (range)10.0 (5-16)9.3 (6-16)9.0 (6-11)9.7 (7-11.9)9.7 (6-12)9.7 (6-16)10 (5-16).03
WBC, × 109/L, median (range)9.0 (1.0-236)17.9 (1.1-179)6.0 (2-46)5.0 (1.1-31)12 (3-179)56.5 (40-236)8 (1-39)< .01
Platelets, × 109/L, median (range)206 (6-1765)93 (6-885)52 (6-522)90 (33-409)157 (17-885)155 (12-1331)214 (7-1765)< .01
PB blast, %, median (range)1.0 (0-18)4 (0-18)2.0 (0-12)5 (0-8)13 (10-18)2 (0-9)1 (0-9)< .01
DIPSS-plus risk group, n (%)< .01
    Low84 (9)0000084 (11)
    Intermediate- 1128 (15)00000128 (17)
    Intermediate- 2332 (38)10 (19)4 (21)1 (13)12 (40)20 (29)295 (39)
    High340 (38)42 (81)15 (79)7 (88)18 (60)48 (71)252 (33)
Constitutional symptoms, n (%)300 (34)21 (40)7 (37)2 (25)16 (53)29 (43)246 (32).08
PB blasts ≥ 1%, n (%)513 (58)45 (87)15 (79)7 (88)32 (100)59 (87)402 (53)< .01
Hemoglobin < 10 g/dL, n (%)491 (56)34 (65)13 (68)5 (63)22 (73)40 (59)411 (54).19
Transfusion required, n (%)347 (39)29 (56)8 (42)7 (88)16 (53)26 (38)289 (38).29
WBC > 25 × 109/L, n (%)145 (16)24 (46)3 (16)1 (13)8 (27)68 (100)65 (9)< .01
Platelets < 100 × 109/L, n (%)231 (26)29 (56)12 (63)5 (63)11 (37)29 (43)177 (23)< .01
WBC < 4 × 109/L, n (%)144 (16)10 (19)6 (32)3 (38)3 (10)0 (0)132 (17)< .01
JAK2V617F, n (%) (n evaluable = 514)308 (60)20/25 (80)8 (100)4 (80)5 (33)23 (70)268 (59).02
MPL mutation, n (%) (n evaluable = 338)28 (8)0/14 (0)0003 (14)25 (8).59
IDH mutation, n (%) (n evaluable = 305)12 (4)0/14 (0)002 (14)1 (5)9 (3).35
Splenectomy, n (%)164 (19)12 (23)3 (16)2 (25)10 (33)22 (32)127 (17)< .01
Cytogenetic categories, n (%)< .01
    Normal516 (58)0009 (30)32 (47)475 (63)
    Favorable239 (27)1 (2)0011 (37)22 (32)206 (27)
    Unfavorable129 (15)51 (98)19 (100)8 (100)10 (33)14 (21)78 (10)
Transplanted, n (%)33 (4)2 (4)1 (5)02 (7)2 (3)28 (4).87
Deaths, n (%)564 (64)46 (89)16 (84)6 (75)29 (97)61 (90)452 (60)< .01
Leukemic transformations, n (%)60 (7)7 (14)5 (26)2 (25)7 (23)6 (9)40 (5)< .01
  • PB indicates peripheral blood; and WBC, white blood cell count.

  • * Very high-risk group constitutes patients with MK, inv(3)/i(17q), or 2 of the following 3 risk factors: circulating blasts > 9%, leukocyte count > 40 × 109/L, or unfavorable karyotype [ie, nonmonosomal complex karyotype or any single or 2 abnormalities including +8, −7/7q−, −5/5q−, inv(3), i(17q), 12p−, or 11q23 rearrangement].

  • “None of the above” refers to patients who did not display MK, inv(3)/i(17q), circulating blasts > 9%, or leukocyte count > 40 × 109/L.

  • P value calculations excluded groups that were defined by the parameters that were being compared.