Table 3.

Independent determinants of blast phase survival duration

Model and factors	P	Hazard ratio
Model 1
Age 60 y or older	.008	2.7
Peripheral blasts 20% or more	.009	2.4
Prior splenectomy	.02	2.5
Model 2
Age 60 y or older	.03	2.3
Peripheral blasts 20% or more	.01	2.4
Prior splenectomy	.03	2.4
Treated for blast phase	.005	0.34

The first multivariate model considers baseline characteristics only. When whether patients received antileukemia therapy was added to the model, treatment emerged as the strongest independent predictor of survival.