Incidence and early prognosis of aneurysmal subarachnoid hemorrhage in Kumamoto Prefecture, Japan.

OBJECTIVE

We analyzed the community incidence and early prognosis of first-ever aneurysmal subarachnoid hemorrhages (SAHs) to obtain the same prognostic information used by physicians and families in a defined geographic area in Japan.

METHODS

During the 5-year period from January 1, 1996, to December 31, 2000, 2115 patients were registered in the Data Bank for Cerebral Aneurysms of Kumamoto Prefecture, a defined area in Japan with a population of 1.86 million. Registration was based on a comprehensive referral system for SAH patients; computed tomographic scans were available for all patients, including those who were moribund or dead on arrival. We compared the treatment outcomes at 3 months after the first-ever SAH in surgically and conservatively treated patients.

RESULTS

The age-adjusted annual incidence of SAH for men, women, and both sexes was 15.9, 26.6, and 21.6 per 100,000 person-years, respectively. In men, the incidence reached a plateau after age 40 years. In women, conversely, it rose after age 40 and peaked in the 9th decade of life. Of the 1634 surgically treated patients, 1153 (70.6%) had a favorable outcome; this was true for only 27 of 477 (5.7%) conservatively treated patients. Four patients were lost to follow-up. The clinical outcome did not differ between patients treated by open surgery and those treated endovascularly. Approximately 30% of our patients were older than 70 years at the time they experienced their first SAH.

CONCLUSION

The incidence of SAH obtained in this study was similar to earlier Japanese reports and Finnish studies. The importance of managing elderly patients with cerebral aneurysms will continue to increase.