Mortality and causes of death in the familial intracranial aneurysm study

Background: Higher mortality for patients with aneurysmal subarachnoid haemorrhage has been reported. Aims: In families with intracranial aneurysms, we sought to determine whether mortality among subjects with intracranial aneurysm (affected) was higher and related to rupture, compared with unaffected family members. Methods: Subjects enrolled in the Familial Intracranial Aneurysm protocol were contacted yearly and their status was obtained. If reported to be deceased, the cause of death was verified by available records. A Cox proportional hazards model was utilized to compare mortality rates. Results: Of the 2794 subjects, 1073 were affected and 1721 were unaffected. There were 8525 person-years of follow-up (mean 3·05±1·73 years) and 85 deaths. Age at study entry for the affected (58·4±11·9 years) was significantly older (P<0·0001) than for the unaffected (52·2±16·1). After adjusting for age, the overall mortality rate for the affected subjects was not significantly different from that for the unaffected (Rate Ratio [RR] 1·26, 95% confidence interval 0·82-1·93, P=0·292). There was a strong effect modification due to age. The mortality rate ratio of the affected to the unaffected who were ≤60 years of age was RR=3·48 (95% confidence interval: 1·59-7·63, P=0·002), the rate for the affected subjects who were ≥60 was less than the rate for the unaffected (RR=0·69, 95% confidence interval: 0·404-1·19, P=0·178). The affected who had ruptures had 2·62 times the mortality rate as those without ruptures (95% confidence interval 1·43-4·80, P=0·002). Conclusion: The overall mortality was similar for the affected and unaffected subjects in this cohort. Among the affected only, those with ruptured intracranial aneurysm had a higher mortality rate than those without ruptured.