The authors investigated the rupture rate among patients with untreated unruptured intracranial aneurysms (UIAs) in South Korea during 2006–2009.
A longitudinal study using national representative health-claim data, including all hospital records for every Korean citizen, was used. Patients with a UIA who were 18–80 years old in 2006 were identified using the I67.1 ICD-10 code. To select eligible patients, a historical period of 1 year prior to the first diagnosis of a UIA in 2006 was utilized. Patients with a previous UIA diagnosis, subarachnoid hemorrhage (SAH), or treatments, such as clipping or coiling, during the historical period were excluded from analysis. Patients with head trauma or a brain tumor during the historical period were also excluded. Eligible patients were followed up for at least 3 years from the index date. Rupture was defined as SAH events with at least 14 days of hospitalization, using the I60 ICD-10 code and excluding the I60.8 code, or death within 14 days of hospitalization.
Seven thousand four hundred four patients with UIAs were identified, including 1441 treated patients (20%) and 5963 untreated patients (80%), with a median follow-up of 3.3 years. Rupture events occurred in 163 (0.9 cases/100 person-years) of the 5963 untreated patients. The rupture rate was highest in the 1st year after UIA diagnosis. An older age was a risk factor for rupture among patients with UIAs.
The overview of the incidence of rupture indicates the need for a preventive strategy and future studies to prevent rupture in Asian patients with UIAs.