Application of IPSET-thrombosis in 1366 Patients Prospectively Followed From the Spanish Registry of Essential Thrombocythemia

Abstract

The International Prognostic Score of thrombosis in Essential Thrombocythemia (IPSET-thrombosis) and its revised version have been proposed to guide thrombosis prevention strategies. We evaluated both classifications to prognosticate thrombosis in 1366 contemporary essential thrombocythemia (ET) patients prospectively followed from the Spanish Registry of ET. The cumulative incidence of thrombosis at 10 years, taking death as a competing risk, was 11.4%. The risk of thrombosis was significantly higher in the high-risk IPSET-thrombosis and high-risk revised IPSET-thrombosis, but no differences were observed among the lower risk categories. Patients allocated in high-risk IPSET-thrombosis (subdistribution hazard ratios [SHR], 3.7 [95% confidence interval, CI, 1.6-8.7]) and high-risk revised IPSET-thrombosis (SHR, 3.2 [95% CI, 1.4-7.45]) showed an increased risk of arterial thrombosis, whereas both scoring systems failed to predict venous thrombosis. The incidence rate of thrombosis in intermediate risk revised IPSET-thrombosis (aged >60 years, JAK2-negative, and no history of thrombosis) was very low regardless of the treatment administered (0.9% and 0% per year with and without cytoreduction, respectively). Dynamic application of the revised IPSET-thrombosis showed a low rate of thrombosis when patients without history of prior thrombosis switched to a higher risk category after reaching 60 years of age. In conclusion, IPSET-thrombosis scores are useful for identifying patients at high risk of arterial thrombosis, whereas they fail to predict venous thrombosis. Controlled studies are needed to determine the appropriate treatment of ET patients assigned to the non-high-risk categories.

Figure 1.

Cumulative incidence of thrombosis taking death as a competing event in 1366 patients prospectively followed from the Spanish Registry of Essential Thrombocythemia. Red line denotes thrombosis and black line death without thrombosis.

Figure 2.

CI of thrombosis according to the IPSET-thrombosis (A, IPSET), revised IPSET-thrombosis (B, IPSET-Rev), and classical risk stratification (C, classic) in 1366 patients prospectively followed from the Spanish Registry of Essential Thrombocythemia. Patients were censored when they change to high-risk category or at 10 years after diagnosis. CI = cumulative incidence; IPSET-thrombosis = International Prognostic Score of Thrombosis in Essential Thrombocythemia.

Figure 3.

ROC curves and area under the curve for the IPSET-thrombosis (IPSET), revised IPSET-thrombosis (IPSET-Rev) and the 2-tier classic prognostic model (classic) are showed for the prediction of total thrombosis (A) and arterial thrombosis (B). The original risk categories of IPSET-thrombosis and revised IPSET-thrombosis have been collapsed into 2strata: high-risk and non-high risk (see text). IPSET-thrombosis = International Prognostic Score of Thrombosis in Essential Thrombocythemia; ROC = receiver operating characteristic.