Background Despite increasing usage of endovascular treatments for intracranial aneurysms, few research studies have been conducted on the incidence of unruptured aneurysm (UA) and subarachnoid hemorrhage (SAH), and could not show a decrease in the incidence of SAH. Moreover, research on socioeconomic disparities with respect to the diagnosis and treatment of UA and SAH is lacking.

Method Trends in the incidences of newly detected UA and SAH and trends in the treatment modalities used were assessed from 2005 to 2015 using the nationwide database of the Korean National Health Insurance Service in South Korea. We also evaluated the influence of demographic characteristics including socioeconomic factors on the incidence and treatment of UA and SAH.

Result The rates of newly detected UA and SAH were 28.3 and 13.7 per 100 000 of the general population, respectively, in 2015. The incidence of UA increased markedly over the 11-year study period, whereas that of SAH decreased slightly. UA patients were more likely to be female, older, employee-insured, and to have high incomes than SAH patients. In 2015, coiling was the most common treatment modality for both UA and SAH patients. Those who were female, employee-insured, or self-employed, with high income were likely to have a higher probability to be treated for UA and SAH.

Conclusion The marked increase in the detection and treatment of UA might have contributed to the decreasing incidence of SAH, though levels of contribution depend on socioeconomic status despite universal medical insurance coverage.