Incidences of unruptured intracranial aneurysms and subarachnoid hemorrhage: results of a statewide study.

Background: The incidence of unruptured intracranial aneurysms (UIAs) and the current public health impact may be higher than that reported in previous studies owing to an increase in the elderly population in the United States.

Objective: To report the current incidences of UIAs and subarachnoid hemorrhages (SAH) by using a population-based methodology.

Methods: Statewide estimates of patients admitted with UIAs and SAH were obtained from the data obtained by the Minnesota Hospital Association. We calculated the annual incidences per 100,000 persons by using the 2010 census data from the U.S. Census Bureau. For the denominator, total persons in each year were categorized into 10-year intervals.

Results: The incidences of UIAs and SAH were 15.6 and 7.7 per 100,000 persons, respectively. There were higher incidences of both UIAs and SAH among women (22.5 and 9.6 per 100,000 persons, respectively). The highest incidence of UIAs occurred in those aged between 75 and 84 years (61.6 per 100,000 persons). The highest incidence of SAH occurred in those aged 85 years and older (30.1 per 100,000 persons).

Conclusion: An increase in both incidences of UIAs and SAH can be expected owing to the continued increase of the elderly population, particularly women.