Background Although
antiplatelet agents are frequently prescribed in
moyamoya disease in routine clinical practice, there are no large-scale epidemiologic trials or randomized trial evidence to support their use in patients with
moyamoya disease. Methods and Results Using the Korean National Health Insurance Service database, patients diagnosed with
moyamoya disease between 2002 and 2016 were followed up for up to 14 years to assess, using time-dependent Cox regression in all patients and in a propensity score-matched cohort, the association of antiplatelet
therapy and individual
antiplatelet agents with survival. Among 25 978 patients with newly diagnosed
moyamoya disease, mean age was 37.6±19.9 years, 61.6% were women, and total follow-up was 163 347 person-years. Among 9154 patients who were prescribed
antiplatelet agents at least once during the follow-up period, the proportion prescribed
cilostazol gradually increased from 5.5% in 2002 to 56.0% in 2016. Any antiplatelet use was associated with reduced risk of death (hazard ratio, 0.77; 95% CI, 0.70-0.84) in a multivariate model. Among individual
antiplatelet agents,
cilostazol was associated with greater reduction in mortality than the 5 other antiplatelet regimens. Subgroup analysis, according to the age group and history of
ischemic stroke, and sensitivity analysis, using propensity score-matched analysis, revealed consistent results. Conclusions Antiplatelet
therapy is associated with substantial improvement in survival in patients with
moyamoya disease, and
cilostazol is associated with greater survival benefit compared with other antiplatelet regimens. These results provisionally support the use of antiplatelet
therapy in patients with
moyamoya disease and the conduct of confirmatory randomized controlled trials.