IPSET-Thrombosis Better Identifies Thrombosis-Free Survival: A Turkish Cohort

Introduction: Essential thrombocythemia (ET) is the most common of the myeloproliferative neoplasms. For better predicting the occurrence of thrombotic events, an International Prognostic Score of Thrombosis for ET (IPSET-Thrombosis) was recently developed. We aimed to investigate the validity of IPSET-Thrombosis in a Turkish patient cohort and to compare the efficacy of IPSET-Thrombosis and conventional risk scoring systems in predicting thrombosis-free survival.

Patients and methods: We retrospectively evaluated the clinical characteristics and risk factors for thrombosis in 112 Turkish patients. Median thrombosis-free survival and Harrell C concordance indexes were calculated for both conventional and IPSET-Thrombosis.

Results: Median age of 112 patients included in the study was 61 (range, 27-90) years at the time of diagnosis. When patients were stratified according to the conventional risk stratification system, 43.8% of patients were in the low-risk group and 56.2% in the high-risk group. A total of 22.4% of low-risk and 42.9% of high-risk patients had at least one thromboembolic event. When patients were stratified according to the IPSET-Thrombosis, 33% were in the low-risk group, 26.8% in the intermediate-risk group, and 40.2% in the high-risk group. Considering IPSET-Thrombosis risk groups, 5.4% of low-risk, 26.7% of intermediate-risk, and 66.2% of high-risk patients had at least one thromboembolic event. Regarding IPSET-Thrombosis risk groups, 10-year thrombosis-free survival was 86.8% for low-risk, 39.4% for intermediate-risk, and 32.9% for high-risk groups (P < .001). Harrell C concordance indexes of conventional and IPSET-Thrombosis were 0.60 and 0.77, respectively.

Conclusion: By validating the reproducibility of IPSET-Thrombosis in Turkish ET patients, we found that IPSET-Thrombosis identifies thrombosis-free survival better than the conventional risk stratification system.