Table 3.

Statistical Comparison of Risk Categories Within the IPSET-thrombosis, Revised IPSET-thrombosis, and the 2-tier Classical Prognostic Model for Thrombosis in ET

Risk Category	SHR (95% CI)	P-value
IPSET-thrombosis		0.002
Intermediate vs low	1.1 (0.5-2.2)
High vs low	2.5 (1.4-4.5)
High vs intermediate	2.3 (1.4-3.9)
Revised IPSET-thrombosis		0.001
Low vs very low	1.0 (0.5-2.2)
Intermediate vs very low	1.0 (0.4-2.4)
Intermediate vs low	1.0 (0.5-2.2)
High vs very low	2.6 (1.4-4.9)
High vs low	2.5 (1.5-4.4)
High vs intermediate	2.5 (1.3-4.8)
Classical 2-tier model		0.005
High vs low	2.2 (1.4-3.3)

SHR and the 95% CIs were estimated in the context of death as a competing risk for thrombosis.

CI = confidence interval; IPSET-thrombosis = International Prognostic Score of Thrombosis in Essential Thrombocythemia; SHR = subdistribution hazard ratios.