Clinical Characteristics and Survival Outcomes in Patients with Essential Thrombocythemia

Essential thrombocythemia (ET) is a myeloproliferative neoplasm characterized by sustained proliferation of megakaryocytes leading to high platelet counts. ET confers risk of thrombosis and vascular complications, which are the main causes of morbidity and mortality. This study aimed to describe disease features, identify thrombosis predictors, and determine prognostic factors for overall survival (OS) in ET patients. This retrospective study analyzed 156 patients with ET diagnosis based on WHO criteria between 2016 and 2021 at Hacettepe University Hospitals. Demographic, clinical, laboratory data, and outcomes including thrombosis events and survival status were extracted from medical records. Factors associated with thrombosis and OS were analyzed. The primary objectives were to [1] define thrombotic risk factors and [2] identify predictors of survival in ET. Median age was 58 years, 66.7% were female, and 46.4% were JAK2-mutated. History of coronary artery disease (CAD) was significantly associated with thrombosis (31.6% vs. 8.8%, p = 0.011). JAK2-mutated patients showed higher prevalence of pro-atherosclerotic comorbidities like diabetes, hypertension and CAD (43.7% vs. 28%, p = 0.044). Lower platelet count (< 728.5 × 109/L), bilirubin and GGT levels correlated with increased thrombotic events. Independent adverse prognostic factors for 5-year OS were bone marrow fibrosis at diagnosis (97.7% vs. 87.5%, p = 0.040), progression to myelofibrosis (97.8% vs. 80.0%, p = 0.039), hypoalbuminemia ≤ 4.34 g/dL (97.7% vs. 94.9%, p = 0.001), and LDL cholesterol ≤ 98.5 mg/dL (100% vs. 91.1%, p = 0.015). JAK2 mutation was associated with inferior OS (p = 0.026). Median follow-up duration was 49.3 months (range: 5.8-83.0 months). Follow-up was longer in mutation-positive patients compared to mutation-negative (52.5 vs. 45.5 months, p = 0.018). According to IPSET scoring, 40.4% were low-risk, 25.6% intermediate, and 34% high-risk. R-IPSET classification yielded 26.9% very low, 13.5% low, 28.2% intermediate, and 31.4% high-risk. Kaplan-Meier survival analysis revealed statistically significant survival differences between R-IPSET groups (p = 0.027), but not among classic IPSET (p = 0.156). Readily assessable clinical and laboratory parameters can refine risk prediction for thrombosis and survival outcomes in ET. Further research is warranted to validate findings and inform individualized management approaches.