Prognostic Factors of Kvasnicka et al for Idiopathic Osteomyelofibrosis

 

Prognostic factors associated with poor survival by univariate analysis (page 714):

(1) age > 70 years

(2) hemoglobin <= 10 g/dL

(3) platelet count <= 300,000 per µL

(4) WBC count >= 20,000 per µL

(5) increased myeloblasts and promyelocytes (presumably in the peripheral blood, based on data in Table 1, page 714)

 

NOTE: The use of ">", ">=", "<" and "<=" differ for age, hemoglobin and platelet count from data used below.

 

Cox Regression Model

 

risk score =

= LN(hazard ratio) =

= (0.0508 * ((age in years) – 64.87)) – (0.1538 * ((hemoglobin in g/dL) – 11.82)) + (0.0322 * ((WBC count in 10^9/L) + 14.31)) + (0.1077 * ((percent myeloblasts) – 1.03))

 

Risk Score (see Note)	Risk Group	5 Year Survival	Life Expectancy
< 0.5	low	79%	21.67 +/- 3.92
0.5 – 1.0	intermediate	58%	8.64 +/- 2.17
> 1.0	high	31%	3.32 +/- 0.90

from Table 3, page 716

 

NOTE: This column in Table 3 is listed as the "hazard ratio". Based on the risk score equation (above), the hazard ratio should be EXP(risk score). If data consistent with low risk is supplied, it is difficult to get the risk score below 0.1. Also, data giving low risk by the CART model (below) can give a risk score > 1. If the EXP(risk score) were used in the table, then unreasonable results would be returned.

 

Classification and Regression Tree (CART) Model

 

Low risk group:

(1) age < 70 years, hemoglobin >= 10 g/dL, WBC count < 20,000 per µL

 

Intermediate risk group:

(1) age < 70 years, hemoglobin < 10 g/dL

(2) age < 70 years, hemoglobin >= 10 g/dL, WBC count >= 20,000 per µL

(3) age >= 70 years, platelet count >= 300,000 per µL, WBC count < 20,000 per µL

 

High risk group:

(1) age >= 70 years, platelet count < 300,000 per µL

(2) age >= 70 years, platelet count >= 300,000 per µL, WBC count >= 20,000 per µL

Risk Group	5 Year Survival	Life Expectancy
low	88%	22.07 +/- 3.34
intermediate	44%	6.54 +/- 2.09
high	18%	2.25 +/- 0.62

from Figure 5 and Table 4, page 717