Five-year population-based study of essential thrombocythemia in Taiwan: Epidemiology, treatment patterns, and sex-based disparities

BACKGROUND: Essential thrombocythemia (ET) is a chronic myeloproliferative neoplasm characterized by sustained thrombocytosis and an elevated risk of thrombotic events. Despite growing clinical relevance, population-based data on ET incidence, prevalence, treatment patterns, and sex-specific differences remain limited in Asia. OBJECTIVES: To evaluate the epidemiologic trends, treatment patterns, and sex-based differences in ET patients in Taiwan from 2017 to 2021, using a nationwide administrative database. METHODS: This retrospective, population-based study utilized the Taiwan National Health Insurance Research Database to identify newly diagnosed ET patients between 2017 and 2021. Case identification was based on ICD-10-CM code D47.3, with confirmation via two or more coded visits at least 90 days apart. Patients were stratified by sex and treatment regimen, including observation, anti-platelet (anti-PLT) monotherapy, hydroxyurea monotherapy, anagrelide monotherapy, or HU + ANA combination therapy. Trends in incidence, prevalence, medication exposure, thrombosis, myelofibrosis, and mortality were analyzed. RESULTS: A total of 3776 new ET cases were identified (60 % female). Incidence rates remained stable from 2017 to 2020, followed by a sharp decline in 2021. Prevalence steadily increased in both sexes, with consistently higher rates in females. Medication patterns showed rising use of watchful waiting and declining anagrelide use over time. Patients prescribed hydroxyurea demonstrated reduced thrombosis risk compared to those who received only anti-PLT therapy. CONCLUSIONS: This population-based study highlights increasing ET prevalence and evolving treatment patterns in Taiwan, with tentative sex-based differences in age distribution and therapeutic response. Findings underscore the need for individualized, risk-adapted management and support ongoing surveillance to inform policy and clinical practice in Asian populations.