gms | German Medical Science

Objective: This study was designed to provide nation-wide epidemiology of moyamoya disease (MMD) in Korea, and to identify long-term effect of direct revascularization surgery for MMD.

Method: For epidemiology, we used database by National Health Insurance System. To elucidate the effect of surgery, we retrospectively investigated the age at diagnosis, sex, surgical methods and occurrence of stroke in 441 cases of adult MMD with ischemic presentation. Surgical treatment was done on 301 cases, and 140 cases were managed conservatively. Annual stroke rate, 1-year, 5-year and 10-year cumulative stroke rates were calculated using survival analysis.

Results: The estimated standardized prevalence was 6.5 in 2005 and increased to 18.1 in 2013 per 100,000 persons. In the same period, standardized incidence increased from 2.7 to 4.3 per 100,000 persons. In retrospective study, the annual rate of any kind of stroke was 1.6% after revascularization while it was 1.9% in conservative group. Ten-year cumulative incidence rates of all stroke were 9.4% vs. 19.6% (p = 0.041). Relative risk reduction was 52.0% and the number needed to treat was 10. The gap of 10-year cumulative incidences of ischemic stroke was more prominent (3.9% vs. 13.3%, P = 0.019). Relative risk reduction was raised to 70.7% and the number needed to treat was 11. However, the difference of cumulative incidence rates at 1-year and 5-year did not reach the level of statistical significance. As to hemorrhagic stroke, revascularization surgery was not superior to conservative management.

Conclusions: The standardized prevalence and incidence of MMD were 18.1 and 4.3 in 2013. Direct or combined revascularization for adult MMD with ischemic presentation can prevent further stroke, and relative risk reduction was 52.0% in 10-year follow-up.