The probability of sudden death from rupture of intracranial aneurysms: A meta-analysis

OBJECTIVE: To estimate the proportion of patients with aneurysmal subarachnoid hemorrhage (SAH) who die before receiving medical attention. METHODS: We performed a systematic literature review. RESULTS: Eighteen population-based: studies between 1965 and 2001 described the incidence of death from SAH before the patients received medical attention. The; combined overall risk of sudden death was 12.4% (95% confidence interval, 11-14%): Patient level analysis was possible for two studies. No significant association between age and sudden death was identified. Aneurysms in the posterior circulation had an ? estimated probability of sudden death of 44:7% (95% confidence interval, 7.4-86%). Statistical sensitivity analysis was performed to examine some possible causes for the heterogeneity between the studies. Study factors statistically associated with;a higher rate of sudden death include origin in England, computed tomographic scans not available for diagnosis, inclusion of patients with SAH from arteriovenous malformations; lower or not stated rate of autopsy for deaths in the community, and a higher-rate of patients with confirmed aneurysms. CONCLUSION: The combined overall estimated risk of sudden death was 12.4% for aneurysmal SAH and 44.7% for posterior circulation aneurysms. However, there are several sources of heterogeneity or possible bias in the reported studies. Further information on patient and aneurysm characteristics is required.