Aneurysmal subarachnoid hemorrhage in Izumo City and Shimane Prefecture of Japan. Outcome.

The overall outcome of patients with aneurysmal subarachnoid hemorrhage was investigated in Izumo City and Shimane Prefecture. Of the patients from Izumo City, the clinical grade on admission was Grade I or II in 41% and Grade IV or V in 31%. Of those from Shimane Prefecture, 49% were graded as Grade I or II and 24% as Grade IV or V. The overall mortality rates 1 year after subarachnoid hemorrhage were 46% for Izumo City and 35% for Shimane Prefecture, while the surgical mortality rates were 18 and 15%, respectively. The mortality rates were particularly high among the elderly over the age of 70 years and among unoperated cases. The leading cause of death in these cases was the effect of aneurysm rupture itself, followed by rebleeding and vasospasm. The 5-year survival probabilities according to life table analysis were 50% for Izumo City and 59% for Shimane Prefecture, and a significant difference was observed in survival curves between Izumo City and Shimane Prefecture. It is concluded that the smaller the community studied, the less favorable the overall outcome, mainly because of poorer clinical conditions on admission.