Table 1 Clinical characteristics, outcomes, and treatment patterns of patients with secondary erythrocytosis versus World Health Organization-defined polycythemia vera.
From: Phenotypical differences and thrombosis rates in secondary erythrocytosis versus polycythemia vera
Variables | All patients (n = 102) | Secondary erythrocytosis patients (n = 36) | PV patients (n = 66) | P value |
|---|---|---|---|---|
Age at diagnosis, years; median (range) | 61 (19–89) | 57 (19–76) | 63.5 (20–89) | 0.005 |
Males; n (%) | 57 (56) | 27 (75) | 30 (45) | 0.004 |
Serum Epo levels, mIU/mL; median (range) “N” evaluable = 92 (90%) | 2.9 (<1–148) | 10.3 (<1–148) | 2.3 (<1–14.1) | <0.0001 |
Serum Epo level categories: Subnormal/Normal/High; n (%) | 46/39/7 (45/38/7) | 3/26/7 (8/72/19) | 43/13/0 (77/23/0) | <0.0001 |
Hemoglobin, g/L; median (range) “N” evaluable = 100 (98%) | 178.5 (151–223) | 176 (160–206) | 179 (151–223) | 0.89 |
Hematocrit; median (range) “N” evaluable = 99 (97%) | 53.7 (44.6–70.2) | 52.9 (48–60) | 54.2 (44.6–70.2) | 0.12 |
Hematocrit>55%; n (%) “N” evaluable = 99 (97%) | 39 (39) | 9 (25) | 30 (48) | 0.02 |
Platelets, × 109/L; median (range) “N” evaluable = 101 (99%) | 326 (120–995) | 191 (125–476) | 417 (120–995) | <0.0001 |
Platelets > 450 × 109/L; n (%) “N” evaluable = 101 (99%) | 27 (27) | 1 (3) | 26 (40) | <0.0001 |
Leukocytes, × 109/L; median (range) “N” evaluable = 101 (99%) | 8.9 (4.1–20.5) | 7.2 (4.1–15.1) | 10 (4.5–20.5) | <0.0001 |
Leukocytes > 11 × 109/L; n (%) “N” evaluable = 101 (99%) | 24 (24) | 1 (3) | 23 (35) | <0.0001 |
LDH at diagnosis, U/L; median (range) “N” evaluable = 72 (71%) | 216 (126–874) | 182 (126–316) | 247 (157–874) | <0.0001 |
Palpable splenomegaly at diagnosis; n (%) “N” evaluable = 97 (95%) | 16 (16) | 2 (6) | 14 (23) | 0.02 |
Driver mutation status “N” evaluable = 102 (100%) | – | – | – | <0.0001 |
JAK2V617F; n (%) | 61 (60) | 0 | 61 (92) | |
JAK2 exon 12; n (%) | 3 (3) | 0 | 3 (5) | |
JAK2V617F unmutateda; n (%) | 38 (37) | 36 (100) | 2 (3) | |
JAK2 allele frequency; median (range) “N” evaluable = 49 (74%) | – | – | 57.3 (3.67–95.3) | – |
Endogenous erythroid colony testing | – | – | – | 0.0003 |
Performed; n (%) | 20 (20) | 18 (50) | 2 (3) | |
Negative result; n (%) | 18 (90) | 18 (100) | 0 (0) | |
Bone marrow aspirate and biopsy; n (%) | 37 (36) | 11 (31) | 26 (39) | 0.37 |
Conventional PV risk stratification “N” evaluable = 66 (100%) | – | – | – | – |
Low risk; n (%) | – | – | 13 (20) | – |
High risk; n (%) | – | – | 53 (80) | – |
Body mass index; median (range) “N” evaluable = 68 (67%) | 26.5 (17.1–51.6) | 33.4 (27–34.8) | 26 (17.1–51.6) | 0.02 |
Active smoker; n (%) | 19 (18) | 11 (31) | 8 (12) | 0.03 |
Hypertension; n (%) | 43 (42) | 12 (33) | 31 (47) | 0.18 |
Diabetes; n (%) | 17 (17) | 8 (22) | 9 (14) | 0.27 |
Obesity; n (%) “N” evaluable = 68 (67%) | 14 (21) | 3 (75) | 11 (17) | 0.02 |
Hyperlipidemia | 33 (32) | 10 (28) | 23 (35) | 0.46 |
Pulmonary disease | 12 (12) | 4 (11) | 8 (12) | 0.88 |
Obstructive sleep apnea | 15 (15) | 4 (11) | 11 (17) | 0.44 |
Etiologies of secondary erythrocytosis; n (%) “N” evaluable = 36 (100%) | – | – | – | |
Idiopathic | 18 (50) | |||
Smoking/COPD | 8 (22.2) | |||
Smoking + additional factorb | 3 (8.3) | |||
Obstructive sleep apnea | 2 (5.6) | |||
Polycystic kidneys | 2 (5.6) | |||
Sleep apnea + polycystic kidneys | 1 (2.7) | |||
Sleep apnea + liver lesion | 1 (2.7) | |||
Post renal transplant | 1 (2.7) | |||
Therapy regimens (exposure, ever); n (%) | ||||
Phlebotomy | 67 (66) | 17 (47) | 50 (76) | 0.004 |
Aspirin | 82 (80) | 20 (56) | 62 (93) | <0.0001 |
Cytoreduction | 58 (57) | 0 (0) | 58 (88) | <0.0001 |
hydroxyurea | 58 (88) | |||
ruxolitinib | 9 (14) | |||
anagrelide | 4 (6) | |||
interferon | 0 (0) | |||
Fibrotic transformations; n (%) “N” evaluable = 66 (100%) | 6 (6) | – | 6 (9) | – |
Leukemic transformations; n (%) “N” evaluable = 66 (100%) | 0 | – | 0 | – |
Follow-up in months; median (range) | 41 (0.7–238) | 10.2 (0.7–47) | 68.2 (11–238) | <0.0001 |
Deaths; n (%) | 5 (5) | 0 (0) | 5 (8) | 0.03 |
