Sex Difference and Rupture Rate of Intracranial Aneurysms: An Individual Patient Data Meta-Analysis

Area of Science:

• Neurosurgery
• Epidemiology
• Vascular Neurology

Background:

• Previous studies indicated a higher risk of intracranial aneurysm rupture in women compared to men.
• However, female sex was not identified as an independent risk factor, possibly due to confounding variables or insufficient study power.

Purpose of the Study:

• To assess sex differences in intracranial aneurysm rupture rates.
• To determine if these differences persist after accounting for patient- and aneurysm-related risk factors.

Main Methods:

• A meta-analysis of individual patient data from 9 cohorts was conducted, including 9940 patients and 12,193 unruptured intracranial aneurysms.
• Rupture rates were compared between women and men using Cox proportional hazard regression, adjusted for the PHASES score, smoking, and family history.

Main Results:

• The study included 6555 women and 3385 men, with 24,357 person-years of follow-up.
• Women exhibited a higher rupture rate (1.04%/person-years) than men (0.74%/person-years).
• The adjusted hazard ratio for rupture in women versus men was 1.39 (95% CI, 1.02-1.90).

Conclusions:

• Women have a significantly higher risk of intracranial aneurysm rupture compared to men.
• This elevated risk in women is not attributable to differences in known patient or aneurysm risk factors.
• Further research is needed to identify the specific factors contributing to the higher rupture risk in women.