Background and Aims:
The association between age and the incidence and outcome of ischaemic stroke is well established. Its role in aSAH, which has a younger age at onset, is uncertain. Using a population-based statewide study, we examined the incidence and outcome of aSAH with a focus on age as a predictor of outcome.

Methods:
In a statewide (n~500,000) population-based retrospective cohort study of aneurysmal subarachnoid haemorrhage from 2010-2014 we collected data from multiple overlapping sources (administrative databases, digital medical records and death registers). We examined the incidence rate (95% CI) and relative risk of death by 30-days and 1-year using log binomial regression with adjustment for sex and Glasgow Coma Scale.
Results:
Among 237 aSAH (70.0% women) the mean (SD) age was 61.0 (16.6) with 8.9% aged <40 years, 52.3% aged 40-65 years and 38.8% aged >65 years. The incidence rate per 100,000 people per year increased with age: <40 years, 3.48 (95% CI 2.17, 4.79); 40-65 years 16.59 (95% CI 14.09, 19.10); >65 years, 25.66 (95% CI 19.82, 31.52). Those aged >65 years (compared to those aged <40 years) had a higher risk of death at 30 days (RR 1.44, 95% CI 1.15-1.80) and 1 year (RR 1.66 95% CI 1.34, 2.06).

Conclusions:
Although mean age of onset is lesser than for ischaemic stroke, the incidence and outcomes of aSAH are worse in older people. Further investigation of the factors contributing to aneurysm rupture and appropriate management in older people is needed.

OLDER AGE IS ASSOCIATED WITH A HIGHER INCIDENCE AND LOWER SURVIVAL IN A RETROSPECTIVE POPULATION-BASED COHORT OF ANEURYSMAL SUBARACHNOID HAEMORRHAGE