What is the natural history and outcome of aSAH?
The case fatality of aSAH remains high worldwide, with mortality rates from aSAH appearing to have declined in industrialized nations over the past 25 years. One study in the United States reported a decrease of 1% per year from 1979 to 1994. Mortality rates vary widely across published epidemiological studies, ranging from 8% to 67%. Regional variations become apparent when numbers from different studies are compared.