Analysis of aneurysmal subarachnoid hemorrhage as a multistep process

Abstract

AbstractBackground and purposeAneurysmal subarachnoid hemorrhage (ASAH) is a complex disease with higher incidence in women compared to men and in Japan compared to other countries. It was hypothesized that ASAH is consistent with a multistep model of disease. The following assessments were made: (1) the number of steps needed for the disease to occur and (2) whether this number may be different in female versus male and in Japanese versus non‐Japanese patients.MethodsIncidence data were generated from a meta‐analysis on ASAH incidence until 2017, which was supplemented with a literature search from 2017 to April 2023. Age‐ and sex‐adjusted incidences per 10‐year age groups were calculated and the logarithm of age‐specific incidence against the logarithm of age was regressed with least‐squares regression.ResultsIn 2317 ASAH patients a linear relationship between logarithm of incidence and logarithm of age was found with a slope estimate of 3.13 (95% confidence interval 2.60–3.65), consistent with a four‐step process. Similar estimates were found for female, male, Japanese and non‐Japanese patients.ConclusionsOur results suggest that ASAH is a four‐step process, also in subgroups with higher ASAH incidence. Elucidation of the exact nature of these steps can provide important clues for identification of disease mechanisms underlying ASAH.