Incidence and outcome of pediatric moyamoya disease in the Republic of Korea: A nationwide study

BackgroundMoyamoya disease (MMD) is a rare cerebrovascular disorder for which nationwide epidemiological data on the pediatric population are limited. In Korea, the majority of published epidemiologic data on MMD entailed brief study periods and were published many years ago. Moreover, the majority of prior epidemiological studies on MMD have not examined the clinical outcomes associated with cerebral revascularization.AimsTo provide a comprehensive analysis of the recent epidemiological trends and cerebrovascular outcomes associated with pediatric moyamoya disease in Republic of Korea.MethodsA retrospective cohort study was conducted using the Korean National Health Insurance Database, analyzing 4,323 pediatric patients diagnosed with MMD between 2006 and 2021. Prevalence and incidence were assessed in all 4,323 patients, and cerebrovascular outcomes were analyzed in 3,656 of these patients. Patients were categorized into surgical and non-surgical groups, with surgical techniques including indirect bypass (IB), direct bypass (DB), and combined bypass (CB). To evaluate year-to-year variations, linear regression analyses were performed to identify and quantify temporal trends for all measured outcomes.ResultsThe mean observation period for the subjects was 10.3 years, with 12.1 years for the non-surgical group and 9.7 years for the surgical group. The prevalence of pediatric MMD increased from 9.3 to 24.8 per 100,000 between 2006 and 2021. Concurrently, the incidence rate has remained stable at approximately 2.0 per 100,000 since 2010. The surgical rate among prevalent cases has exhibited a gradual increase and has remained at approximately 88% since 2018. Furthermore, the case event rate for stroke has exhibited a downward trend over time, and a statistically significant reduction in hemorrhagic stroke was observed.ConclusionsIn Korea, the prevalence rate of MMD continues to rise, while the incidence rate remains stable despite a reduction in absolute case numbers, reflecting demographic shifts and improved survival. The mortality rate among pediatric MMD patients remained unchanged; however, the incidence of hemorrhagic stroke was found to have decreased. Further multi-institution-based cohort studies are needed to clarify long-term cerebrovascular outcomes in this population.