Epidemiology, Comorbidities, and Healthcare Costs of Prader-Willi Syndrome in South Korea Using the Korean National Health Insurance Service Database.

Background: Prader-Willi syndrome (PWS) is a rare genetic disorder associated with substantial comorbidity and early mortality. However, the epidemiologic burden on Asian populations, particularly in South Korea, remains poorly understood. This study evaluates the nationwide incidence, prevalence, mortality, comorbidities, and healthcare costs of PWS in South Korea. Methods: We conducted a retrospective, population-based cohort study using the Korean National Health Insurance Database from 2005 to 2021. Among 2,553 individuals with PWS-related diagnostic codes, 458 patients were included in the study based on predefined criteria incorporating growth hormone therapy (GHT) or methylation-specific polymerase chain reaction testing. Epidemiologic trends, comorbidities, intensive care unit (ICU) admissions, and healthcare expenditures were analyzed. Results: The overall birth incidence was 6.8 per 100,000 live births, with a significant increase evident after 2016. The median age at diagnosis was 1.0 years, and GHT was initiated at a median age of 2.0 years. The all-cause mortality rate was 3.5%, with pneumonia being the leading cause of death. ICU admission occurred in 25.5% of patients, often during infancy. Intellectual disability and/or developmental delay was present in 68.6% of patients, and type 2 diabetes mellitus in 15.1%. The mean cumulative healthcare cost per patient exceeded 86 million Korean won. Comorbidity prevalence and annual medical costs increased steadily over time. Conclusion: This is the first nationwide study to quantify the long-term epidemiological and economic burden of PWS in South Korea. Our findings underscore the need for early diagnosis, integrated care models, and policy support for this complex population.