Table 2.
Multivariate Analysis of Patient Characteristics and Association With Overall Survival and Blast Phase Development
| Variable | Hazard Ratio | P |
|---|---|---|
| Multivariate analysis for overall survival* | ||
| Age older than 65 years | 1.7 | .001 |
| Male sex | 1.6 | .012 |
| Primary myelofibrosis | 1.6 | .056 |
| Previous hydroxyurea therapy | 1.6 | .013 |
| Performance status (per ECOG unit) | 1.6 | .001 |
| Hemoglobin < 10 g/dL or transfusion dependency | 1.9 | < .001 |
| Platelets < 50 × 109/L | 4.3 | < .001 |
| Peripheral-blood or marrow blasts ≥ 10% | 2.0 | .033 |
| Chromosome 17 abnormality | 4.8 | < .001 |
| Multivariate analysis for blast phase development† | ||
| Performance status (per ECOG unit) | 2.2 | .012 |
| Platelets < 50 × 109/L | 4.1 | .005 |
| Peripheral-blood or marrow blasts ≥ 10% | 4.6 | .006 |
| Chromosome 17 abnormality | 5.5 | .042 |
Abbreviations: ECOG, Eastern Cooperative Oncology Group; P32, radioactive phosphorus.
*
The following were not significant for overall survival: evaluation at diagnosis or later in disease course; WBC count < 4 or > 30 × 109/L; spleen > 20 cm below left costal margin or previous splenectomy; previous alkylator or P32 exposure; and monocytes ≥ 1 × 109/L.
†
The following were not significant for blast phase development: evaluation at diagnosis or later in disease course; primary v secondary myelofibrosis; male sex; hemoglobin < 10 g/dL or transfusion dependency; WBC count < 4 or > 30 × 109/L; and previous hydroxyurea therapy.