Epidemiology of ruptured brain arteriovenous malformation: a National Cohort Study in Korea

OBJECTIVE Brain arteriovenous malformation (BAVM) is a rare cerebrovascular disease that causes intracranial hemorrhage. Although several reports have demonstrated the epidemiological features of BAVM in Western countries, no epidemiological investigations regarding BAVM have been reported in Korea. The authors aimed to investigate the national epidemiology of ruptured BAVM in a Korean population. METHODS The authors used data from the National Health Insurance Service-National Sample Cohort (NHIS-NSC). The original cohort included approximately 1 million individuals (2% of the Korean population) with 12-year claim data (2002-2013). To construct an initial cohort for investigation, the authors selected 1,016,820 registered individuals in 2005. Subjects with a history of cerebrovascular disease (code I6xx) and BAVM (Q282) between 2002 and 2004 were washedout to identify incident cases. During the 9-year follow-up (2005-2013), the incidence of BAVM was calculated using the earliest date of diagnosis of ruptured or unruptured BAVM. Direct standardization was applied to the crude incidence. Mortality and disability were evaluated using registration data. Related diagnostic procedures were also analyzed. RESULTS A total of 8,802,696 person-years of observation were noted. During observation, 308 patients were diagnosed with a ruptured BAVM. The crude incidence of ruptured BAVM was 3.5 per 100,000 person-years. There was no sex difference in incidence. The mortality rate for patients with a ruptured BAVM 1 month after diagnosis was 12.7%. At 1-year and 5-year follow-up examinations, mortality rates were 17.2% and 22.1%, respectively. Severe disability-free survival rates of patients with ruptured AVMs were 75.3% and 69.8% at 1-year and 5-year follow-up, respectively. CONCLUSIONS The standardized incidence of ruptured BAVMs was 3.6 per 100,000 person-years in Korea. Ruptured BAVMs resulted in high mortality and disability rates.