Moyamoya disorder in the United States.

BACKGROUND: In Asian populations, moyamoya disease has a well-defined phenotype including a bimodal age of presentation with children typically presenting with ischemic phenomena and adults presenting with hemorrhage. Studies have provided evidence that moyamoya disease in the United States may exhibit a different phenotype.
OBJECTIVE: To assess overall rates of admission, demographics, procedures, and outcomes of patients admitted or diagnosed with moyamoya disorder in US hospitals.
METHODS: A comprehensive assessment of the Nationwide Inpatient Sample of the Healthcare Cost and Utilization Project (2002-2008) was performed. Patient demographics, comorbidities, procedures, and outcomes were analyzed.
RESULTS: There were 2280 admissions for moyamoya disorder with a predicted national estimate of 11 163 admissions (0.57/100 000 persons/y). Over time, there was a significant increase in diagnosis and associated ischemic strokes. Females (72%) were affected more than males (28%). Demographics included white (49%), black (24%), Hispanic (11%), Asian (11%), and other (3.3%). Mean age at presentation was 31.6 ± 18.0. Children were significantly more likely to be diagnosed with ischemic phenomena (16.4%) than hemorrhage (3.3%), as were adults (18.8% vs 11.0%). Status at discharge was largely routine (74.8%) vs short-term hospital (3%), home health care (7%), transfer to another hospital (12%), or in-hospital death in 2.3%.
CONCLUSION: Patients admitted to US hospitals diagnosed with moyamoya disorder were more commonly female and white, and both adults and children were more likely to be diagnosed with ischemic vs hemorrhagic stroke. Over time, there was an increase in diagnosis, associated ischemic stroke, and treatment with extracranial-intracranial bypass.